Treasury Bill Calculator (Sri Lanka)
Enter your investment, the T-bill yield and tenure (91, 182 or 364 days) to see your after-tax return in LKR.
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How this Treasury Bill calculator works
T-bills are quoted as an annualised yield. We compute Gross interest = Amount × Yield × Days / 365, deduct the 5% withholding tax and show the net return plus the annualised (AER) figure so you can compare across tenures. Sri Lanka T-bills settle at maturity — you receive the face value on day 91, 182 or 364.
T-bill vs FD in Sri Lanka (2026)
T-bills are direct government debt — as safe as it gets in LKR. When yields spike (as they did in 2022–2024) T-bills often pay 1–3% more than bank FDs. FDs are simpler and covered by deposit insurance up to Rs. 1.1M. If you are investing over Rs. 500,000, run the same numbers through our FD calculator and pick the higher after-tax return.
Tips for buying T-bills
Auctions are held every Wednesday and rates change weekly — place your bid the day before through your primary dealer. Retail investors can buy from Rs. 5,000 via the CBSL retail scheme, or from Rs. 100,000 through any licensed bank. Reinvest maturities into the next auction to compound the yield.
Frequently Asked Questions
What is a Treasury Bill in Sri Lanka?
A Treasury Bill (T-bill) is a short-term government debt security issued by the Central Bank of Sri Lanka in tenures of 91, 182 and 364 days. It is sold at a discount and redeemed at face value on maturity — the difference is your interest. T-bills are considered the safest LKR investment because they are backed by the government.
How do I buy Treasury Bills in Sri Lanka?
You buy T-bills through any licensed commercial bank or registered primary dealer. Minimum investment is usually Rs. 100,000 (or Rs. 5,000 via the central bank retail scheme). Weekly auctions publish rates every Wednesday.
Are T-bill returns taxed in Sri Lanka?
Yes. A 5% withholding tax (WHT) is deducted at source on T-bill interest in Sri Lanka in 2026. This is a final tax for most individual investors, so no further tax is due. This calculator shows both gross and after-WHT returns.
T-bill vs Fixed Deposit — which is better?
T-bills are backed by the government and usually match or beat bank FD rates, especially during high-rate periods. FDs are simpler and can be under the deposit insurance scheme. When T-bill yields are 1%+ above 1-year FD rates, T-bills are usually the better choice for lump sums over Rs. 100,000.
Can I sell a T-bill before maturity?
Yes — T-bills are tradable in the secondary market via your primary dealer. The price depends on prevailing yields, so you may get more or less than the accrued value. Most retail investors simply hold to maturity for the certain return.
What is the current T-bill rate in Sri Lanka?
T-bill yields move with central bank policy rates and are announced weekly. Check the latest weekly auction results before locking in — even 0.5% on a Rs. 1M investment is Rs. 5,000.
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