CPF OA Interest Formula Explained, With Examples
Every cpf oa interest result comes from one formula. Once you understand what goes into it, you can sanity-check any figure you are given, whether by an employer, a bank, a teacher or another website.
The formula
Uses monthly compounding as an approximation of CPF's monthly accrual and annual crediting.
What each input means
- Current OA balance (S$): the value you enter in the calculator.
- Monthly contribution (S$): the value you enter in the calculator.
- Years: the value you enter in the calculator.
- Interest rate (%): the value you enter in the calculator.
Example
For example, with these inputs:
- Current OA balance (S$): 50,000
- Monthly contribution (S$): 1,000
- Years: 10
- Interest rate (%): 2.5
the calculator returns:
- Projected OA balance: S$200,356.52
- Interest earned: S$30,356.52
How the result changes
The table keeps the other inputs at their example values and changes current oa balance (s$).
| Current OA balance (S$) | Projected OA balance | Interest earned |
|---|---|---|
| 50,000 | S$200,356.52 | S$30,356.52 |
| 25,000 | S$168,264.23 | S$23,264.23 |
| 37,500 | S$184,310.37 | S$26,810.37 |
| 62,500 | S$216,402.66 | S$33,902.66 |
| 75,000 | S$232,448.81 | S$37,448.81 |
Why it matters
In Singapore, payslip maths decides how much you can save, invest and spend, and CPF takes a sizeable share before the money reaches your bank account. Knowing the numbers in advance makes salary negotiations, job switches and budgeting far less of a guess.
Contribution rates fall as workers get older, to keep older workers employable while their retirement savings continue to grow. The Government has been raising rates for workers above 55 in stages since 2022, with the latest change in January 2026 and another planned for 2027, so figures for senior workers change more often than for younger employees.
CPF distinguishes between ordinary wages, which are paid for work in the month such as basic salary and fixed allowances, and additional wages, such as annual bonuses and leave encashment. Ordinary wages are capped at S$8,000 a month from January 2026, while additional wages are capped by an annual ceiling of S$102,000 minus the ordinary wages already subject to CPF in the year.
Payslips must be itemised, showing basic pay, allowances, overtime, deductions and CPF. Comparing a payslip against an independent calculation is the easiest way to catch mistakes, especially in the first month of a new job, after a pay rise, or when you cross an age band.
Related calculations
- CPF Contribution Calculator: Works out the monthly CPF contribution for Singapore Citizens and third-year-onwards PRs, split into employee and employer shares, using the 2026 rates and the S$8,000 Ordinary Wage ceiling.
- Take-Home Pay Calculator: Shows what lands in your bank account each month after the employee CPF deduction, for Singapore Citizens and full-rate PRs.
- Employer CPF & Hiring Cost Calculator: Estimates the full monthly cost of employing a local worker: salary, employer CPF and the Skills Development Levy.
- CPF on Bonus (Additional Wage) Calculator: Calculates CPF on a bonus or other additional wage using the AW ceiling of S$102,000 minus the ordinary wages already subject to CPF in the year.
Use the CPF OA Interest Calculator to plug in your own numbers.
Run your own numbers: CPF OA Interest Calculator