CPF Special Account Interest Formula Explained, With Examples
Every cpf special account 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
Future value with monthly compounding: B(1+r)^n + m((1+r)^n − 1)/r.
What each input means
- Current SA 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 SA balance (S$): 30,000
- Monthly contribution (S$): 300
- Years: 15
- Interest rate (%): 4
the calculator returns:
- Projected SA balance: S$128,436.20
- Interest earned: S$44,436.20
How the result changes
The table keeps the other inputs at their example values and changes current sa balance (s$).
| Current SA balance (S$) | Projected SA balance | Interest earned |
|---|---|---|
| 30,000 | S$128,436.20 | S$44,436.20 |
| 15,000 | S$101,131.67 | S$32,131.67 |
| 22,500 | S$114,783.93 | S$38,283.93 |
| 37,500 | S$142,088.46 | S$50,588.46 |
| 45,000 | S$155,740.72 | S$56,740.72 |
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.
Total compensation in Singapore is more than the number on your offer letter. Employer CPF, variable bonuses, the Annual Wage Supplement (often called the 13th month) and benefits all add value, and comparing offers on take-home pay alone can hide meaningful differences.
The Central Provident Fund is Singapore's mandatory savings scheme for citizens and permanent residents. Contributions are shared between employee and employer and flow into the Ordinary Account for housing, education and investment, the Special Account for retirement, and MediSave for healthcare. Because the money is locked up for specific purposes, many people underestimate how much of their total pay it represents.
Related calculations
- CPF Allocation Calculator (OA, SA, MA): Shows how each month's 37% CPF contribution is split between your Ordinary, Special and MediSave accounts by age group.
- Overtime Pay Calculator (MOM): Uses the Ministry of Manpower formula to work out the hourly basic rate and overtime pay for employees covered by Part IV of the Employment Act.
- Monthly to Hourly Rate Calculator: Converts a monthly salary into the hourly rate MOM uses for overtime and deductions.
- Daily Rate of Pay Calculator: Finds the daily rate of pay used for public holiday work, rest days and unpaid leave deductions.
Use the CPF Special Account Interest Calculator to plug in your own numbers.
Run your own numbers: CPF Special Account Interest Calculator