Calculation Methodology

What each of the 49 tools on this site actually computes, and which published document it computes it from. Nothing here is a black box: if you disagree with a result, this page tells you exactly which rule we applied so you can check it against the source yourself.

Each tool below links to its own page, where the same method is shown alongside worked examples and a dated revision history. Our editorial & review policy sets out how often each is re-checked.

Sri Lanka Bank & Branch Code Finder

Matches bank and branch names or their codes. A branch is always shown with its bank because branch codes can repeat. Leading zeros are preserved when displaying and copying codes.

Last reviewed:

HariTools is an independent reference tool. Confirm current bank and branch details with your bank before making a payment.

Income Tax Calculator Sri Lanka (APIT)

Applies IRD APIT Table 01 to monthly regular employment income, then deducts estimated employee EPF from take-home pay.

Last reviewed:
Rules effective:
1 April 2025 - IRD Table 01 for 2025/2026, latest listed on the IRD APIT tables page at review

This is an estimate for regular primary employment income. Payroll treatment can differ for secondary employment, lump-sum payments, non-cash benefits, exemptions, and EPF-eligible earnings.

Cost to Company Calculator Sri Lanka

Treats basic salary plus EPF-eligible allowances as the contribution base, deducts employee EPF at 8% from gross pay, and adds employer EPF at 12% and ETF at 3% on top of gross to arrive at total cost to company.

Last reviewed:
Rules effective:
Statutory minimum EPF and ETF rates

Statutory minimums only. Which allowances are EPF-eligible is a question of fact about your pay structure, and many employers contribute above the minimum. Gratuity, APIT, insurance, and other benefits sit outside this calculation.

Freelancer Hourly Rate Calculator (USD to LKR)

Converts billable hours per week into monthly hours at 4.33 weeks per month, adds business expenses to the target take-home to get the amount that must be earned, then divides by monthly hours. The planning rate divides that figure by 0.70 so there is room in gross revenue for an assumed 20% margin and 10% tax reserve. Those are fixed examples for planning, not Sri Lankan tax rates.

Last reviewed:
Rules effective:
Planning assumptions, not statutory rates

The 20% margin and 10% tax provision are planning defaults chosen for this tool, not rates set by any authority. Your actual tax liability depends on your total income and the current personal income tax bands, and the exchange rate you receive depends on your bank and payment processor.

Vehicle Lease Calculator Sri Lanka

Calculates a fixed reducing-balance EMI and compares the financed share of the entered vehicle value with the selected CBSL maximum LTV category.

Last reviewed:
Rules effective:
25 May 2026

The vehicle category and value accepted by a lender can differ from your input. Lenders may apply a lower LTV and additional credit, income, security, fee, and insurance requirements.

Loan Eligibility Calculator Sri Lanka

Subtracts entered existing liabilities from the user-selected share of net income, then converts the remaining monthly amount into a reducing-balance loan scenario.

Last reviewed:

This is not a lender's eligibility model, approval decision, affordability advice, or loan offer. There is no universal DBR or card-limit percentage used by every Sri Lankan lender and product.

EPF and ETF Calculator Sri Lanka

Projects annual EPF and ETF balances from statutory minimum contribution rates and the salary-growth and annual-return assumptions entered by the user.

Last reviewed:

This is an illustrative projection, not an EPF, ETF, or IRD statement. It excludes withdrawals and tax and cannot predict future declared interest or dividends.

Fixed Deposit Calculator Sri Lanka

Uses simple interest on the entered fixed deposit, annual rate and term. Deducts 10% advance income tax when selected, then shows either monthly interest or principal plus net interest at maturity. It does not calculate Treasury bill yields.

Last reviewed:
Rules effective:
10% AIT on deposit interest from 1 April 2025

This is a fixed-deposit simple-interest estimate. Bank payout and compounding terms can differ. The AIT switch is an assumption; only turn it off if your bank confirms an exemption or valid self-declaration.

Gratuity Calculator Sri Lanka (Payment of Gratuity Act)

Applies the two Section 5 formulas - half a month's wage per completed year for monthly-rated employees, fourteen days' wage per completed year for daily and piece-rated employees - to the last drawn wage, gated by the five-year qualifying period and the fifteen-employee coverage threshold.

Last reviewed:
Rules effective:
Payment of Gratuity Act No. 12 of 1983

This is an estimate of the statutory minimum. A contract, collective agreement, or company policy can provide more, and the treatment of a final part-year varies between employers. Gratuity disputes are handled by the Commissioner of Labour.

Home Loan Calculator Sri Lanka with Upfront Costs

Applies the reducing-balance annuity formula to the loan amount. For an illustrative Western Province freehold sale, estimates stamp duty on assessed value at 3% of the first Rs. 100,000 and 4% of the remainder. Adds entered fees and down payment to estimate upfront cash.

Last reviewed:
Rules effective:
Western Province freehold sale stamp-duty example

A fixed-rate loan scenario and a Western Province freehold transfer duty example. Property duty is administered by provinces and depends on the transaction and assessed value. Confirm exact duty, fees and rate-reset terms with the notary and lender.

Hire Purchase Calculator (Flat Rate to True Rate)

Applies flat interest to the amount financed for the full term, divides the total by the number of instalments, then solves numerically for the reducing-balance rate that would produce the same instalment.

Last reviewed:

An estimate from the figures entered. Agreements vary in how they treat insurance, registration, and early settlement, and the settlement figure on a flat-rate agreement is set by the contract rather than by recalculating interest.

Government Pension Calculator Sri Lanka

Multiplies the pensionable monthly salary entered by the visitor by the applicable pension percentage they supply. It does not infer a percentage from service years.

Last reviewed:
Rules effective:
Department of Pensions circular and applicable pension table

The applicable percentage and pensionable salary must come from the authority handling your pension. Different salary bands, service periods, retirement dates and reduced rates can produce different outcomes. This worksheet does not determine entitlement or a final payable amount.

Sri Lanka Import Duty & Landed Cost Calculator

Uses the Customs 2026 guide: duty, Cess and PAL on CIF; percentage Excise on CIF plus 15% with those levies; surcharge on duty; and VAT and SSCL on CIF plus 10% with duty, Cess, PAL, Excise and surcharge. A supplied Special Commodity Levy total replaces the other levies.

Last reviewed:
Rules effective:
National Imports Tariff Guide 2026

This models the entered rates and unit-rate totals. HS-code classification, exemptions, preferential rates, Special Commodity Levy and other product-specific rules must be confirmed in the current Customs tariff or with a clearing agent.

Final Exam & Assignment Grade Calculator

Treats the module as a weighted average. It totals the marks already earned against their weights, subtracts that from the target, and divides the shortfall by the weight the final examination carries to give the score required on it.

Last reviewed:

Arithmetic on the weights you enter. It assumes marks combine as a straight weighted average, which is not true where a module has a separate pass condition on the examination component, applies scaling or moderation, or caps a resit.

University Attendance Calculator (80% Rule)

Divides lectures attended by lectures conducted. Where you are above the target it solves for how many further sessions can be missed before you drop below it; where you are below, it solves for the run of consecutive sessions needed to climb back.

Last reviewed:
Rules effective:
Example 80% attendance target

The 80% threshold is the common requirement, but the rule that binds you is your own faculty's. Some departments set 85%, count practicals separately from lectures, or treat medical leave differently. Check your handbook before relying on a margin.

GPA Calculator Sri Lanka for University Students

Calculates a credit-weighted GPA using the selected grade-point mapping and optional degree-class guide.

Last reviewed:

Sri Lankan universities and faculties do not all use the same grade points, repeat rules, exclusions, or degree-class thresholds. Verify the mapping against your current student handbook.

A/L Z-Score Calculator Sri Lanka

Standardises each subject using the entered mean and standard deviation, then averages the three subject z-scores. The built-in statistics are illustrative, so the result is not an official Z-score.

Last reviewed:
Rules effective:
University admission policy, 40/55/5 quota split

This calculates the Z-score itself, not an admission outcome. Cut-off marks are published only after the full cohort is processed, and they differ by course, district, and quota. It does not include a cut-off dataset.

O/L Results Calculator & A/L Eligibility Checker

Counts result-sheet grades at S or above as passes and C or above as credits, then checks the commonly used A/L entry conditions when all nine grades are entered.

Last reviewed:
Rules effective:
Department of Examinations grading scale

The eligibility conditions shown are the ones commonly applied, not a decision. The rule binding each cohort is set by circular, and individual A/L streams add their own subject requirements. Confirm with your school.

Cambridge & Edexcel Grade Converter (9-1 to A*-G)

Uses the three alignment points the awarding bodies fix between the two scales - grade 7 to A, grade 4 to C, and grade 1 to G - and interpolates the rest, marking which is which. Mixed sets are averaged on the numeric scale, with letter grades taking the midpoint of the numbers they span.

Last reviewed:
Rules effective:
9-1 and A*-G scales as published by the awarding bodies

No Sri Lankan authority publishes an official equivalence between international grades and local qualifications. The O/L column is indicative only, and every university, professional body, and employer sets its own recognition rule.

Sri Lanka University Cut-off Checker (Z-Score)

Compares the entered Z-score against the UGC minimum Z-score for the chosen district, course by course. The table was transcribed from the UGC PDF by script and verified cell for cell against a second independent extraction: 260 course rows across 25 districts, 6,500 values, all matching. NQC cells are carried as null and never compared as zero.

Last reviewed:
Rules effective:
2025/2026 admission, published 31 July 2026

A cut-off is the outcome of one year's competition, not a threshold carried forward. Meeting a past cut-off does not guarantee selection, and the UGC's own published table is the authority for any decision that matters.

Pregnancy Due Date (EDD) Calculator

Adds 280 days to the first day of the last menstrual period, adjusted by the difference between your cycle length and a 28-day cycle. When a conception date is entered instead, it works back 14 days to an equivalent LMP before applying the same rule.

Last reviewed:
Rules effective:
Naegele's rule, cycle-length adjusted

An estimated date, not an appointment. Only about one birth in twenty happens on the estimated due date, and a dating ultrasound in the first trimester is more accurate than any calculation from dates. Follow the guidance of your midwife or obstetrician.

Ovulation and Fertile Window Calculator

Estimates ovulation by subtracting the selected luteal-phase assumption from the next period predicted from the entered average cycle length.

Last reviewed:

This educational calendar estimate cannot confirm ovulation, fertility, pregnancy, or a medical condition and must not be used as contraception. It has not been individually reviewed by a clinician.

Age & Date Difference Calculator

Subtracts the two calendar dates the way a person would by hand, borrowing days from the preceding month and months from the year. Both dates are built from their parts in local time, so the result is the same calendar difference for a reader anywhere in the world.

Last reviewed:

Calendar arithmetic on the proleptic Gregorian calendar. Where a legal age threshold matters, confirm the rule that applies -- some jurisdictions count an age as attained on the day before the anniversary.

South Asian BMI & Ideal Weight Calculator

Computes BMI as weight in kilograms divided by height in metres squared, then classifies it against the lower cut-offs the WHO recommends for Asian populations rather than the international thresholds. The healthy weight range is derived from the same 18.5 to 22.9 band.

Last reviewed:
Rules effective:
WHO Asian-population BMI cut-offs

BMI is a population screening measure, not a diagnosis. It does not distinguish muscle from fat and is unreliable for athletes, pregnant women, children, and older adults. Discuss any concern about your weight with a doctor rather than acting on this number alone.

BMR and Daily Calorie Calculator

Calculates basal metabolic rate with Mifflin-St Jeor, multiplies by a standard activity factor for total daily energy expenditure, and adds the calorie change implied by the selected goal at 7,700 kcal per kilogram of body fat.

Last reviewed:
Rules effective:
Mifflin-St Jeor equation

A population estimate, not a personal prescription. Individual metabolic rates vary by around 10% either way. Anyone who is pregnant, managing a medical condition, or planning a large deficit should speak to a doctor or dietitian first.

Blood Donation Eligibility Date Calculator

Adds four months to the last whole blood donation date, clamping to the end of a shorter month, and checks the entered age and weight against the National Blood Transfusion Service donor criteria.

Last reviewed:
Rules effective:
NBTS donor criteria

Only the criteria that can be checked from a date and two numbers. Illness, medication, surgery, tattoos, pregnancy, travel history, and haemoglobin are assessed at the centre on the day and can defer a donor regardless of this result.

Income Tax Calculator Sri Lanka (APIT)

Applies IRD APIT Table 01 to monthly regular employment income, then deducts estimated employee EPF from take-home pay.

Last reviewed:
Rules effective:
1 April 2025 - IRD Table 01 for 2025/2026, latest listed on the IRD APIT tables page at review

This is an estimate for regular primary employment income. Payroll treatment can differ for secondary employment, lump-sum payments, non-cash benefits, exemptions, and EPF-eligible earnings.

VAT & SSCL Invoice Calculator

Applies the selected SSCL rate to the entered base and VAT to the base plus SSCL, or reverses the same calculation for an inclusive total.

Last reviewed:
Rules effective:
VAT 18% and SSCL 2.5% from 1 January 2024; SSCL registration threshold lowered during 2026

SSCL is charged on liable turnover, which varies by activity, and exemptions may apply. Confirm registration, liable-turnover percentage, invoicing, and filing treatment with IRD or a tax professional.

Cost to Company Calculator Sri Lanka

Treats basic salary plus EPF-eligible allowances as the contribution base, deducts employee EPF at 8% from gross pay, and adds employer EPF at 12% and ETF at 3% on top of gross to arrive at total cost to company.

Last reviewed:
Rules effective:
Statutory minimum EPF and ETF rates

Statutory minimums only. Which allowances are EPF-eligible is a question of fact about your pay structure, and many employers contribute above the minimum. Gratuity, APIT, insurance, and other benefits sit outside this calculation.

Freelancer Hourly Rate Calculator (USD to LKR)

Converts billable hours per week into monthly hours at 4.33 weeks per month, adds business expenses to the target take-home to get the amount that must be earned, then divides by monthly hours. The planning rate divides that figure by 0.70 so there is room in gross revenue for an assumed 20% margin and 10% tax reserve. Those are fixed examples for planning, not Sri Lankan tax rates.

Last reviewed:
Rules effective:
Planning assumptions, not statutory rates

The 20% margin and 10% tax provision are planning defaults chosen for this tool, not rates set by any authority. Your actual tax liability depends on your total income and the current personal income tax bands, and the exchange rate you receive depends on your bank and payment processor.

Retail Margin, Markup & Discount Calculator

Adds cost of goods to shipping and packaging to get total unit cost, then solves for the selling price that leaves the target gross margin using price = cost divided by one minus the margin. Markup is reported as profit over cost, and the discount simulation recalculates margin at the reduced price.

Last reviewed:

Gross margin only. It excludes rent, salaries, marketing, payment fees, returns, and any tax on the sale, so a healthy gross margin here does not by itself mean the business is profitable.

EPF and ETF Calculator Sri Lanka

Projects annual EPF and ETF balances from statutory minimum contribution rates and the salary-growth and annual-return assumptions entered by the user.

Last reviewed:

This is an illustrative projection, not an EPF, ETF, or IRD statement. It excludes withdrawals and tax and cannot predict future declared interest or dividends.

Gratuity Calculator Sri Lanka (Payment of Gratuity Act)

Applies the two Section 5 formulas - half a month's wage per completed year for monthly-rated employees, fourteen days' wage per completed year for daily and piece-rated employees - to the last drawn wage, gated by the five-year qualifying period and the fifteen-employee coverage threshold.

Last reviewed:
Rules effective:
Payment of Gratuity Act No. 12 of 1983

This is an estimate of the statutory minimum. A contract, collective agreement, or company policy can provide more, and the treatment of a final part-year varies between employers. Gratuity disputes are handled by the Commissioner of Labour.

Hire Purchase Calculator (Flat Rate to True Rate)

Applies flat interest to the amount financed for the full term, divides the total by the number of instalments, then solves numerically for the reducing-balance rate that would produce the same instalment.

Last reviewed:

An estimate from the figures entered. Agreements vary in how they treat insurance, registration, and early settlement, and the settlement figure on a flat-rate agreement is set by the contract rather than by recalculating interest.

Break-Even Point Calculator

Divides fixed costs by contribution per unit, where contribution is price minus variable cost. Margin of safety compares expected volume against the break-even volume, and the target-profit figure treats the desired profit as an addition to fixed costs.

Last reviewed:

A gross-margin model for a single product at a single price. It excludes tax, and assumes every cost is cleanly either fixed or variable, which real cost structures rarely are.

Sri Lanka Import Duty & Landed Cost Calculator

Uses the Customs 2026 guide: duty, Cess and PAL on CIF; percentage Excise on CIF plus 15% with those levies; surcharge on duty; and VAT and SSCL on CIF plus 10% with duty, Cess, PAL, Excise and surcharge. A supplied Special Commodity Levy total replaces the other levies.

Last reviewed:
Rules effective:
National Imports Tariff Guide 2026

This models the entered rates and unit-rate totals. HS-code classification, exemptions, preferential rates, Special Commodity Levy and other product-specific rules must be confirmed in the current Customs tariff or with a clearing agent.

Sri Lanka Bank & Branch Code Finder

Matches bank and branch names or their codes. A branch is always shown with its bank because branch codes can repeat. Leading zeros are preserved when displaying and copying codes.

Last reviewed:

HariTools is an independent reference tool. Confirm current bank and branch details with your bank before making a payment.

Sri Lanka Administrative Division Finder

Matches division names and newer GN codes, then shows the parent DS Division, district and province. Check the full hierarchy because names and short codes can repeat. Older MPA numbers and complete Location Codes are not included.

Last reviewed:

HariTools is an independent reference tool. Confirm names and current administrative details with the relevant office before completing official forms.

Sri Lanka Postal Code Finder

Search by location name in English, Sinhala or Tamil, or enter all five digits of a postal code. When several offices share a code, check the location, district and province to choose the right one.

Last reviewed:

HariTools is an independent reference tool. Confirm missing or uncertain results with the relevant post office.

Age & Date Difference Calculator

Subtracts the two calendar dates the way a person would by hand, borrowing days from the preceding month and months from the year. Both dates are built from their parts in local time, so the result is the same calendar difference for a reader anywhere in the world.

Last reviewed:

Calendar arithmetic on the proleptic Gregorian calendar. Where a legal age threshold matters, confirm the rule that applies -- some jurisdictions count an age as attained on the day before the anniversary.

Fuel Cost & Road Trip Split Calculator

Divides trip distance by the vehicle's fuel efficiency to get litres consumed, multiplies by the price per litre, and divides the total between the number of people sharing. A round trip doubles the distance before anything else is calculated.

Last reviewed:

Fuel only. Tolls, parking, wear, and any difference between your real-world consumption and the efficiency figure entered are not included, so the true cost of a trip is higher than the number shown.

Everyday Percentage Calculator

Handles the three distinct questions people mean by percentage: a share of a whole, one number expressed as a percentage of another, and the change between two numbers. Each uses its own formula, shown alongside the result.

Last reviewed:

Pure arithmetic with no rounding applied beyond display. Where a percentage carries legal or financial consequence, check the rounding convention the institution applies.

Tip & Bill Split Calculator

Applies the tip percentage to the bill amount entered, adds it to the total, and divides by the number of people. Rounding options adjust the per-person figure to a convenient note value.

Last reviewed:

Primary sources

Whether you tip on the pre-tax or post-tax amount is a personal choice, not a rule. Check whether a service charge has already been added before deciding what to leave.

Everyday Unit Converter

Converts through a single base unit per category -- metres for length, kilograms for weight -- using exact SI-defined factors. Temperature is converted through Celsius, since its scales differ by offset as well as by ratio.

Last reviewed:
Rules effective:
SI definitions

Conversion factors are exact by definition, so results are limited only by display rounding. Where a tolerance matters, carry the full precision rather than the rounded figure shown.

Sri Lanka NIC Number Decoder

Splits the number into its year, day-of-year, and serial fields, removes the 500 offset that marks a female holder, and resolves the day-of-year against the fixed 366-day calendar the Department of Registration of Persons encodes against.

Last reviewed:
Rules effective:
12-digit format, issued since 2016

This tool reads what a number encodes. It cannot confirm that a number was issued, that it is still current, or that it belongs to a particular person - no published check-digit algorithm exists for the Sri Lankan NIC.

Sri Lanka Public Holidays and Poya Days 2026 & 2027

Dates are taken from the Holidays in Sri Lanka calendar Google publishes as a public ICS feed, transcribed by script rather than by hand. Moon-sighting dependent dates are carried through with the source's own tentative flag, and long weekends are computed by scanning the year for runs of consecutive days off.

Last reviewed:
Rules effective:
2026 and 2027 calendar years

The definitive list for any year is the gazette published by the Ministry of Public Administration. Islamic holidays depend on a moon sighting and can move by a day. Ad-hoc holidays declared during the year - for elections or other reasons - cannot appear on a page prepared in advance.

Sources we cite

Every document any tool on this site is built from, and the tools that depend on it. 56 primary sources in total.