Compound Interest Calculator for Singapore

How to use the calculator

1. Enter your numbers. Starting amount, monthly deposit and how many years you can leave it invested.
2. Pick a rate. Tap a Singapore preset (CPF, SSB, T-bills, fixed deposits, equities) or type your own.
3. Check the real picture. Open Advanced options for yearly pay rises, inflation and fees. The goal planner shows the deposit you need for a target.
4. Share or download. Send a link that restores your exact numbers, or save the schedule as Excel, CSV, image or PDF.

What is compound interest?

Compound interest is interest earned on your original money and on the interest already added to it. Each period's interest joins the balance, so the next period's interest is calculated on a bigger amount. Simple interest, by contrast, is paid only on the original amount.

The gap grows with time. S$10,000 at 5% a year earns a flat S$500 every year with simple interest, ending at S$20,000 after 20 years. With annual compounding it ends at S$26,533 without you adding a dollar. Add S$500 a month and the same 5% reaches S$229,435 on S$130,000 deposited. The mechanism is identical; the results are not.

A worked example: S$10,000 plus S$300 a month at 5% a year, compounded monthly for 25 years, becomes about S$213,466. You deposited S$100,000, so S$113,466 (53% of the final balance) is interest. The first five years reach only S$33,235, yet the last five add S$63,029 — that is the curve compounding creates.

How we calculate it

Transparency matters more than a pretty number, so here is exactly what the calculator does. Every figure on the page can be reproduced with a spreadsheet — the Excel download contains the formulas.

• r is your annual rate less any fees; n is how many times a year it compounds (12 for monthly, 365 for daily, and so on).
• Your rate and compounding frequency are converted into an equivalent monthly growth factor, so a deposit made mid-year earns its fair share of that year's growth even under annual compounding. Calculators that credit deposits only at year-end show slightly lower results for annual compounding.
• Deposits are made monthly, at month-end by default (the standard annuity convention) or month-start if you choose. You can raise them by a fixed percentage each year.
• The goal planner solves for the monthly deposit exactly: the final balance is linear in the deposit, so no guesswork or iteration is needed.
• Not modelled: market volatility, taxes, currency moves, or CPF's own method (interest computed monthly on the lowest balance and credited annually). The CPF section below explains how to approximate it.

What moves your result most

1. Time: starting earlier beats saving more

Saving S$200 a month from 25 to 65 at 7% builds about S$524,963 from S$96,000 deposited. Saving double — S$400 a month — but only from 35 to 65 builds S$487,988 from S$144,000. The earlier saver deposits S$48,000 less and still finishes ahead. At 6%, S$500 a month for 40 years reaches S$995,745; for 30 years only S$502,258. Waiting ten years halves the result.

2. Deposits: automate them

The formula rewards consistency. A standing order or GIRO removes the monthly decision and keeps every deposit working. Raising your deposit with pay (try 3% a year in Advanced options) usually matters more than chasing a slightly higher rate.

3. Fees: small percentages, big gaps

A 1% yearly cost on a 7% return leaves you with a 6% net return. On S$500 a month for 30 years that is S$609,985 versus S$502,258 — about S$107,700 (18%) less. On a one-off S$10,000 the gap is 26%. Compare total expense ratios and platform fees, and enter them in the Fees field.

4. Inflation: plan in today's dollars

At 2% inflation, S$1,000,000 in 20 years buys what S$672,971 buys today; in 30 years, S$552,071; in 40 years, S$452,890. MAS's July 2026 outlook projects 2026 core inflation of 1.5–2.5%, and core inflation was 2.0% in July. Look at the "today's dollars" figure when you set a goal.

5. Compounding frequency: real, but minor

S$10,000 at 5% for 20 years ends at S$26,533 with annual compounding, S$27,126 monthly and S$27,181 daily. Annual to monthly adds S$593; monthly to daily adds S$55. Choose the frequency your product actually uses, then spend your effort on rate, time and fees.

6. Reinvest, and use tax-advantaged accounts

Distributions you spend stop compounding; reinvested ones start new clocks. CPF and SRS offer guaranteed rates or tax deductions, so fill those buckets before taxable accounts if their lock-in suits you. Interest on Singapore bank deposits and debt securities is generally not taxable for individuals, and Singapore has no general capital gains tax — but check IRAS for your situation.

Frequently asked questions

Sources

Rates snapshot as at 12 October 2026. CPF, SSB, tax and inflation figures come from the primary sources below. Fixed-deposit, savings-account and T-bill figures are not published in one official place, so they come from independent rate compilations and are shown as ranges.

• CPF Board — What are the CPF interest rates? (OA 2.5%, SA/MA/RA 4%, extra interest tiers, Oct–Dec 2026)
• MAS — Singapore Savings Bonds; November 2026 tranche rates as published on our SSB interest rate tracker
• Growbeansprout — T-bills vs fixed deposits vs SSB, October 2026 (T-bill cut-off, fixed-deposit and savings-account rates compiled from bank boards, 7–8 Oct 2026)
• MAS — Monetary Policy Statement, July 2026 (2026 core inflation outlook 1.5–2.5%)
• IRAS — Individual income tax rates and SRS contributions and tax relief; tax on SRS withdrawals
• IRAS — Interest income
• MSCI — MSCI World Index (USD) factsheet, as at 30 September 2026
• REITAS — Overview of the S-REIT industry (average distribution yield about 6.3% at 30 June 2026)
• SDIC — Singapore Deposit Insurance Corporation (S$100,000 per depositor per bank)