Compound Interest Calculator Singapore (2026)

CPF Special Account (SA), MediSave Account (MA), and Retirement Account (RA) balances earn at least 4.0% p.a. — a floor set by the CPF Board and effectively backed by the Singapore government. An additional 1% is paid on the first $60,000 of combined CPF balances (capped at $20,000 for OA). For a fully government-guaranteed 4% return that compounds annually, CPF SA/MA is the safest option for Singapore residents.

CPF interest is computed monthly and credited at the end of each calendar year. Ordinary Account (OA) pays at least 2.5% p.a.; SA, MA, and RA pay at least 4.0%. The extra 1% on the first $60,000 of combined balances (max $20k from OA) gives effective rates of up to 3.5% for OA and 5% for SA/MA in that tier. Because interest compounds annually, contributions made early in your career grow significantly larger than later contributions — small monthly tops-ups can add up substantially over 30+ years.

T-bills (6-month and 1-year) and Singapore Savings Bonds (SSBs) are short-to-medium term, capital-protected MAS instruments. T-bills typically yield close to short-term policy rates (recently 3.5–4%), while SSBs offer step-up rates that average towards 10-year SGS yields if held to maturity. Neither truly "compounds" in the traditional sense — T-bills pay a fixed discount at issuance; SSBs pay interest every 6 months. To compound, you must reinvest each payout. They are excellent low-risk vehicles but require active reinvestment to mimic true compounding.

Yes, most Singapore savings accounts compound interest monthly or daily, though base rates are typically very low (0.05–0.5%). Higher-yield bank accounts like DBS Multiplier, OCBC 360, UOB One, and Standard Chartered Bonus$aver offer tiered bonus rates up to 4–7% on capped balances if you meet salary credit, spend, and investment criteria. These rates are not guaranteed and the qualifying amounts cap the effective yield on larger balances. Read the tier structure carefully — many "headline" rates only apply to a specific balance band.

Interest income from CPF, Singapore bank deposits, SSBs, T-bills, SGS bonds, and most approved deposit-taking institutions in Singapore is tax-exempt for individuals — Singapore does not tax interest income paid by approved local institutions to resident individuals. This is a major advantage for compounding: the full pre-tax rate is your effective rate. Interest from foreign banks or overseas bonds may be taxable in Singapore if received locally, and may also face withholding tax in the source country. Always confirm with IRAS guidance for non-standard sources.

The Rule of 72 estimates how long it takes for an investment to double: divide 72 by the annual rate. At CPF SA 4%, money doubles in roughly 18 years (72 ÷ 4). At T-bill 3.5%, it doubles in about 20.6 years. At a high-yield bank account giving 5%, it doubles in about 14.4 years. At a low-yield bank account giving 0.5%, it doubles in 144 years — illustrating why parking large sums in low-yield savings is costly. The rule is approximate; the precise formula is ln(2) / ln(1 + r), but Rule of 72 is accurate enough for rates between 2–10%.

Simple interest pays only on the original principal: $10,000 at 5% simple for 20 years = $10,000 + ($500 × 20) = $20,000. Compound interest pays on principal AND accumulated interest: $10,000 at 5% compounded annually for 20 years = $26,533. The difference grows exponentially with time. Most Singapore savings and investment products use compound interest. Some loans (like certain HDB and bank mortgages) effectively charge compound interest on outstanding balances, which is why early loan repayment saves more than the headline rate suggests.

More frequent compounding means interest is added back to your balance more often, so subsequent interest is calculated on a slightly higher balance. At 4% p.a., $10,000 compounded annually grows to $10,400 after one year; compounded monthly it grows to about $10,407 (effective annual rate 4.074%). The difference is small at low rates and short horizons but adds up over decades. For most Singapore retail products, the headline rate is already quoted as an effective annual rate (EAR) for fair comparison — check whether your product quotes nominal or effective rate when comparing.