How to Calculate CPF Special Account Interest in Singapore: A Step-by-Step Guide
Projects Special Account growth at the 4% floor rate.
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.
What you need
- Current SA balance (S$)
- Monthly contribution (S$)
- Years
- Interest rate (%)
Step by step
- Enter the current sa balance (S$).
- Enter the monthly contribution (S$).
- Enter the years.
- Enter the interest rate (%).
- The results update as you type, or press Calculate.
- Read the projected sa balance first, then the supporting figures below it.
The formula
Future value with monthly compounding: B(1+r)^n + m((1+r)^n − 1)/r.
Worked 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$44,436.20
A second example
Now change the inputs to:
- Current SA balance (S$): 37,500
- Monthly contribution (S$): 300
- Years: 15
- Interest rate (%): 4
the calculator returns:
- Projected SA balance: S$142,088.46
- Interest earned: S$50,588.46
Practical tips
- Overtime eligibility depends on your salary and role under Part IV of the Employment Act, not just your job title.
- Employer CPF is not part of your take-home pay, but it is part of your total compensation, so count it when comparing offers.
- Remember the S$8,000 monthly Ordinary Wage ceiling from January 2026: salary above it does not attract CPF.
- If you change jobs mid-year, the Additional Wage ceiling is calculated across all employers for the calendar year.
Background
The Employment Act sets out how hourly and daily rates are calculated for overtime, public holiday work and salary deductions. These formulas use the monthly basic rate of pay rather than gross salary, which is why the numbers can look lower than a simple division of your salary by hours worked.
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.
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.
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.
Want to skip the arithmetic? The free CPF Special Account Interest Calculator does all of this instantly and updates as you type.
Run your own numbers: CPF Special Account Interest Calculator