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I am Tharindu De Silva, a dedicated banking professional with a strong passion for treasury operations, capital markets, and financial analytics. With hands-on experience in treasury management and a keen interest in developing practical tools, I built this suite of calculators to assist professionals in making informed decisions. I believe in continuous learning and sharing knowledge to empower the financial community.
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Professional calculators for Treasury, Banking, Capital Markets & Personal Finance — all in one trusted platform.
Price, yield, accrued interest and capital gain/loss calculations for Treasury Bills (A/364).
Bond pricing, YTM, accrued interest, amortization, gain/loss and duration/convexity analytics.
Equity valuation, profitability, return and cost of equity measures.
Spot, forward, swap points and swap value calculations for FX.
Repo interest, maturity amount and collateral exposure / minimum face value required.
Mortgage, EMI, auto loan, compound interest, retirement, ROI and NPV/IRR calculators.
Allocate cash across T-Bills, T-Bonds, Equity, and FDs. Track unallocated funds and manage multi-deal portfolios.
Calculate individual income tax payable based on Sri Lanka Inland Revenue Department rules (effective 1 April 2025).
Individual tax calculation based on Inland Revenue Department rules — effective 1 April 2025
Calculate your annual income tax payable under Sri Lankan Inland Revenue Department rules. Enter your total assessable income and qualifying payments, and this calculator will apply the 2025/26 progressive tax slabs and personal relief of LKR 1,800,000 to give you your total tax payable, effective tax rate, approximate monthly APIT, and a slab-by-slab breakdown.
Who is this for: Resident and non-resident individuals who need a quick, clear tax estimate. How to use it: Enter your annual assessable income (total income before relief), any qualifying payments, then click Calculate Tax.
| Taxable Income (LKR) | Tax Rate |
|---|---|
| First 1,000,000 | 6% |
| Next 500,000 | 18% |
| Next 500,000 | 24% |
| Next 500,000 | 30% |
| Balance | 36% |
Source: Inland Revenue (Amendment) Act, No. 02 of 2025 — effective 1 April 2025. Personal relief increased from LKR 1,200,000 to LKR 1,800,000.
Assessable Income is the total income received or derived during the Year of Assessment from the following sources, before deducting Personal Relief or Qualifying Payments:
Do not include income that is specifically exempt or excluded under the Inland Revenue Act (for example, certain terminal benefits, approved pension income, or exempt investment gains as defined in the Act). Only enter the taxable portion of your total income here.
The IRD website explicitly states that donations made in money to an Approved Charity are deductible from Assessable Income as a Qualifying Payment.
The deductible amount is limited to the lowest of the following three values:
The Inland Revenue Act lists other qualifying payments (e.g., contributions for Samurdhi shop establishment, film industry expenditure), but their current-year applicability and caps are not confirmed in the IRD documents available at the time of this update. Only enter amounts you can substantiate as valid Qualifying Payments for the relevant Year of Assessment. If unsure, enter 0 to avoid an inaccurate tax computation.
Treasury Bill pricing and yield calculations (A/364 day count)
Work out the price of a Treasury Bill from the settlement date, maturity date, purchase yield, and face value. The calculator uses the A/364 (or A/360 for US convention) day-count basis to return the clean price per 100 of face value and the settlement value in currency.
How to use it: Enter the settlement date, maturity date, the yield you purchased at (as a %), the face value, then click Calculate. What you get: Days to maturity, T-Bill price per 100, and settlement value — useful for pricing a new deal or verifying a broker's quote.
Work out the annualised yield on a Treasury Bill from its purchase price and the number of days to maturity. Uses the standard money-market yield formula under the selected A/364 or A/360 basis.
How to use it: Enter the purchase price, settlement date and maturity date, choose the day-count basis, then click Calculate. What you get: Days to maturity and the implied T-Bill yield (%) — useful for comparing different bills on a like-for-like basis.
Calculate the accrued interest (the increase in the bill's effective value since purchase) as of any required date between settlement and maturity. Also returns a day-by-day detail breakup showing how the effective price and accrued value build up.
How to use it: Enter the required date, the original settlement date, maturity date, purchase yield, and face value. What you get: Purchased price, effective price at the required date, accrued interest in currency, and a full daily accrual table you can export to Excel.
Calculate the capital gain or loss when you sell a T-Bill before maturity. The calculator compares the effective value of your purchase (as of the sell date) with the selling value based on the selling yield.
How to use it: Enter the buy deal (purchase date, maturity, purchase yield) and the sell deal (sell date, sell yield, sell face value). What you get: Effective value of the purchase as on the sell date, selling value, and the resulting capital gain or loss — useful for mark-to-market and P&L reporting.
Government bond pricing, yield, accrued interest and gain/loss (A/A day count)
Calculate the clean price, dirty price, accrued interest, and settlement values of a Treasury Bond from its settlement date, maturity, coupon rate, yield to maturity, face value, and coupon frequency.
How to use it: Fill in all fields, choose the coupon frequency and day-count basis (A/A default), then click Calculate. What you get: Accrued interest per 100, clean price, dirty price, clean value and dirty value — everything you need to settle a bond trade.
Back out the Yield to Maturity (YTM) of a Treasury Bond from its current market price, coupon rate, and time to maturity. Uses Newton–Raphson iteration on the standard bond-pricing formula.
How to use it: Enter the market price (per 100), coupon rate, coupon frequency, and the required/maturity dates. What you get: Days to maturity, current yield and the YTM — useful for comparing bonds with different coupons and prices.
Calculate the coupon interest that has accrued on a Treasury Bond since its last coupon date, up to any required date. Returns both the accrued interest per 100 of face value and the equivalent currency amount, plus a day-by-day breakdown.
How to use it: Enter the required date, maturity date, face value, coupon rate, coupon frequency, and day-count basis. What you get: Last coupon date, next coupon date, accrued per 100, accrued currency amount, and a detailed daily accrual table you can export to Excel.
Compute the amortised book value of a Treasury Bond from purchase through to any required date, using your choice of Constant Yield, Constant EIR, or Straight-Line amortization. The calculator shows the day-by-day schedule and reconciles clean price, accrued interest and cash flows.
How to use it: Enter the required date, purchase date, maturity, coupon rate, purchased yield, face value and amortization method. What you get: Total amortised amount as of the required date, amortised book value, unamortised amount, and a detailed table with export to Excel.
Calculate the capital gain or loss when a Treasury Bond is sold before maturity. The calculator compares the amortised book value of the purchase (as on the selling date) with the selling value based on the selling yield.
How to use it: Enter the buy deal (purchase date, maturity, coupon rate, purchase yield) and the sell deal (sell date, sell yield, sell face value). What you get: Amortised value of the purchase on the sell date, selling value, and the resulting capital gain/loss — useful for portfolio P&L.
Calculate Macaulay Duration, Modified Duration and Convexity for a Treasury Bond, and see how the bond's clean price responds to a yield shock. Includes a visual price–yield curve showing the duration tangent and convexity curvature.
How to use it: Enter the settlement and maturity dates, coupon rate, YTM, face value, coupon frequency, and the yield shock in basis points. What you get: Clean price, Macaulay/MD, convexity, and the ΔPrice estimates from duration alone vs. duration + convexity — useful for interest-rate risk management.
Equity valuation, dividend, profitability and return calculations
Value a stock using the Gordon Growth Dividend Discount Model. The intrinsic value is the present value of all future dividends, assuming a constant dividend growth rate forever.
How to use it: Enter the current dividend per share (D₀), expected dividend growth rate, required rate of return (cost of equity), and optionally the current market price. What you get: Expected dividend next year (D₁), intrinsic value per share, and the upside/downside versus the current market price — useful for value investing and equity research.
Calculate the trailing and forward Price-to-Earnings (P/E) ratios for a stock, and compare against the sector average. P/E is a quick valuation metric best used within the same industry.
How to use it: Enter the current market price, trailing EPS, and optionally forward EPS and the sector average P/E. What you get: Trailing P/E, forward P/E, sector P/E, and a valuation verdict (undervalued / overvalued / in line) — useful for relative valuation.
Calculate the dividend yield (annual dividend per share ÷ current market price) and the yield on cost (annual dividend ÷ original purchase price) for a stock.
How to use it: Enter the annual dividend per share, current market price, and optionally your purchase cost. What you get: Dividend yield %, yield on cost %, and the annual income per 1,000 shares — useful for income investors and dividend-growth portfolios.
Calculate the total return on an equity investment over a specific holding period, including both capital gains and dividends. Also returns the annualised HPR for easy comparison.
How to use it: Enter the purchase price, sale/current price, total dividends received, and the holding period in days. What you get: HPR %, annualised HPR %, and the split between capital gain and dividend return — useful for performance measurement.
Calculate the Price-to-Book (P/B) ratio of a stock by comparing its market price to its book value per share. P/B is especially useful for valuing banks and financial institutions.
How to use it: Enter the current market price, total book value of equity, shares outstanding, and optionally the sector average P/B. What you get: Book value per share, P/B ratio, and a valuation verdict vs. the sector.
Calculate basic EPS and diluted EPS from net income, preferred dividends and shares outstanding. Dilution shows the impact of potential new shares (options, convertibles) on earnings per share.
How to use it: Enter net income, preferred dividends, basic shares outstanding, and optionally diluted shares. What you get: Basic EPS, diluted EPS, and the dilution impact % — useful for equity valuation and performance analysis.
Calculate the Sustainable Growth Rate (SGR) — the maximum rate a company can grow its revenue and earnings without raising new external equity, given its ROE and dividend payout ratio.
How to use it: Enter net income, dividends paid and shareholders' equity. What you get: ROE, payout ratio, retention ratio, and the SGR — useful for fundamental growth analysis.
Calculate the required rate of return on an equity using the Capital Asset Pricing Model (CAPM), which links the risk-free rate, market risk premium and the stock's beta.
How to use it: Enter the risk-free rate (e.g. 10-year government bond yield), the stock's beta, and the expected market return. What you get: The market risk premium, required rate of return (cost of equity), and a quick interpretation of the beta (defensive / neutral / aggressive).
Value a company's equity using a Free Cash Flow to Equity (FCFE) model. Projects FCFE over an explicit forecast period, adds a Gordon-growth terminal value, and discounts everything at the cost of equity.
How to use it: Enter current FCFE, the explicit-period growth rate and number of years, terminal growth rate, cost of equity, shares outstanding, and optionally net debt. What you get: PV of explicit FCFE, terminal value, equity value, and value per share — useful for fundamental stock valuation.
Calculate the PEG ratio — the Price-to-Earnings ratio divided by expected EPS growth. PEG adjusts P/E for growth and is a favourite metric for growth investors.
How to use it: Enter the P/E ratio and the expected EPS growth rate (as a %). What you get: PEG ratio and a plain-language interpretation (PEG < 1 suggests undervaluation, > 1 overvaluation).
Foreign exchange spot, forward, swap points and swap value calculations
Calculate the outright forward exchange rate from the spot rate and the interest rate differential between two currencies, based on Interest Rate Parity.
How to use it: Enter the spot rate, the base-currency and quote-currency interest rates (% p.a.), the tenor in days, and the day-count basis. What you get: Spot rate, forward points, and outright forward rate — useful for hedging and cross-currency pricing.
Calculate the swap points (forward – spot) and the annualised forward premium/discount from the spot rate, interest rates, and tenor. Swap points are normally quoted in pips in the interbank market.
How to use it: Enter the spot rate, base and quote interest rates, tenor, and day-count basis. What you get: Swap points per unit, swap points in pips, and annualised forward premium/discount % — useful for FX swap pricing.
Calculate the near-leg and far-leg cash flows of an FX swap from the spot rate, swap points, and base notional. Also returns the net quote-currency cash flow between the two legs.
How to use it: Enter the spot rate, swap points (in pips), base notional amount, and tenor. What you get: Near-leg base and quote amounts, far-leg forward rate and quote amount, and the net quote-currency cash flow — useful for FX swap confirmation and reconciliation.
Repo interest and collateral exposure calculations
Calculate the total repo interest, maturity amount, and the collateral exposure / minimum face value of securities required to cover a repo transaction, given a haircut and market price.
How to use it: Enter principal, repo rate, investment and maturity dates, day-count basis, plus collateral type, haircut and market price. What you get: Total interest, per-day interest, maturity amount, total exposure to be covered, and minimum face value required — useful for money-market operations and collateral management.
Everyday money tools — loans, savings, retirement and returns
Calculate the monthly principal & interest payment on a home loan, plus optional taxes and insurance. See the total interest you will pay over the life of the loan and a yearly amortization summary.
How to use it: Enter loan amount, annual interest rate, loan term, and optionally down payment, property tax and insurance. What you get: Monthly P&I, monthly tax + insurance, total monthly payment, total interest paid, and a yearly amortization table you can export.
Calculate the Equated Monthly Instalment (EMI) for any loan, along with total interest, total payment, processing fee, and total cost of borrowing.
How to use it: Enter loan amount, annual interest rate, tenure (years or months), and optionally a processing fee %. What you get: Monthly EMI, total interest payable, total payment, processing fee, total cost of loan, and number of EMIs — useful for comparing loan offers.
Calculate the monthly car payment, total interest, sales tax and total upfront cost from the vehicle price, down payment, trade-in, sales tax %, interest rate, and loan term.
How to use it: Enter vehicle price, down payment, trade-in, sales tax %, annual interest rate, and term in months. What you get: Amount financed, monthly payment, total interest paid, total of all payments, sales tax amount, and total upfront cost — useful for car financing decisions.
Calculate the future value of a lump-sum investment plus regular monthly contributions, using either a standard compounding frequency or a money-market daily-accrual basis. See the split between contributions and interest earned, plus the Effective Annual Rate (EAR).
How to use it: Choose the compounding mode, enter initial principal, annual rate, number of years, optional monthly contribution, and rounding. What you get: Total contributions, total interest, future value, EAR, and a yearly growth schedule you can export.
Project the corpus you will accumulate by retirement based on your current savings, monthly contributions, and expected return. Then estimate the monthly income that corpus can support, in today's money, after inflation.
How to use it: Enter current age, retirement age, current savings, monthly savings, expected return, inflation, and life expectancy. What you get: Corpus at retirement, monthly income in today's money, total contributions, and total growth earned — useful for retirement planning.
Calculate simple ROI and annualised ROI for any investment, with day-count basis support. Useful for comparing investments of different lengths on a like-for-like basis.
How to use it: Enter initial investment, final value, any additional costs, holding period in years, and a day-count basis. What you get: Net profit, ROI %, annualised ROI %, total cost basis, and effective days used.
Calculate the Net Present Value (NPV), Internal Rate of Return (IRR / XIRR), payback period and Profitability Index (PI) of an investment. Choose between annual periods (IRR) and irregular dated cash flows (XIRR).
How to use it: Enter initial investment, discount rate, and choose the cash-flow mode. For annual mode, enter a comma-separated list of yearly cash flows. For dated mode, enter each cash flow with its date. What you get: NPV, IRR/XIRR, payback period, PI and a verdict (Accept / Reject) — useful for capital budgeting and project appraisal.
Calculate your annual income tax payable under the Sri Lankan Inland Revenue Department rules (effective 1 April 2025). Uses progressive slabs and personal relief of LKR 1,800,000.
How to use it: Enter your annual assessable income, any qualifying payments, and rounding. What you get: Assessable income, personal relief, taxable income, total tax payable, effective tax rate, approximate monthly APIT, and a slab-by-slab breakdown.
| Taxable Income (LKR) | Tax Rate |
|---|---|
| First 1,000,000 | 6% |
| Next 500,000 | 18% |
| Next 500,000 | 24% |
| Next 500,000 | 30% |
| Balance | 36% |
Source: Inland Revenue (Amendment) Act, No. 02 of 2025 — effective 1 April 2025. Personal relief increased from LKR 1,200,000 to LKR 1,800,000.
Assessable Income is the total income received or derived during the Year of Assessment from the following sources, before deducting Personal Relief or Qualifying Payments:
Do not include income that is specifically exempt or excluded under the Inland Revenue Act (for example, certain terminal benefits, approved pension income, or exempt investment gains as defined in the Act). Only enter the taxable portion of your total income here.
The IRD website explicitly states that donations made in money to an Approved Charity are deductible from Assessable Income as a Qualifying Payment.
The deductible amount is limited to the lowest of the following three values:
The Inland Revenue Act lists other qualifying payments (e.g., contributions for Samurdhi shop establishment, film industry expenditure), but their current-year applicability and caps are not confirmed in the IRD documents available at the time of this update. Only enter amounts you can substantiate as valid Qualifying Payments for the relevant Year of Assessment. If unsure, enter 0 to avoid an inaccurate tax computation.
Allocate your cash across different investment instruments
Plan a multi-deal portfolio across T-Bills, T-Bonds, Equity and Fixed Deposits. Enter your total cash, set an investment date and a target income date, and allocate your funds across instruments. The planner tracks unallocated cash and warns you if you over-allocate.
How to use it: Enter cash in hand, investment date and total income required date. Tick the instruments you want, add deals, and enter allocations (or proportions). What you get: A live dashboard of cash in hand, allocated funds and unallocated funds, plus a full portfolio results page with income projection and charts.
This page shows the projected performance of your portfolio plan. It includes a visual allocation donut, cash and allocation summary, per-product deal tables (T-Bills, T-Bonds, Equity, FDs) and an income bar chart — all as of your selected "Total Income Required Date".
How to use it: Review the results, then click "Back to Portfolio Planner" to adjust allocations. T-Bond amortised values are shown using the Constant Yield Method with Semi-Annual coupon frequency.