SOURCES & VALIDATION
CPF calculation methods and checks
By Jia Hui · Reviewed 8 November 2026
This is a free, non-profit personal project for illustrative planning. It is not an official CPF service, financial advice, or certification of a retirement plan. Use with discretion and verify important decisions independently.
What the model calculates
The planner tracks accessible savings, CPF accounts, optional CPFIS and SRS separately. It applies monthly cash flows and investment assumptions, checks for unfunded spending and searches whole retirement ages through 65. It uses published 2026 CPF tables and announced 2027 employment rates; later policy and returns remain assumptions.
Current ages are 18–64. Exact birthdays, opening-year accrued interest, payroll dates, all CPF transactions and actuarial CPF LIFE pricing are not available. Synthetic market tests illustrate uncertainty; they do not provide calibrated probabilities of success.
The RA reference comparison
Our initial January-start comparison included ten full years of earned interest and was 2.03–2.56% above the six examples in CPF's current payout FAQ. A later check separates interest already credited to RA from interest earned but not yet credited.
With a July start, no contributions or withdrawals, the full 120 months still elapse from 55 to 65. At that date, the credited balance excludes the final half-year's uncredited interest. Rounding that credited balance down to S$100 reproduces all six selected FAQ figures:
| RA at 55 | CPF FAQ at 65 | July-start credited RA | Rounded down to S$100 |
|---|---|---|---|
| 50,000.00 | 82,400.00 | 82,455.27 | 82,400.00 |
| 110,200.00 | 170,100.00 | 170,150.95 | 170,100.00 |
| 150,000.00 | 227,900.00 | 227,931.71 | 227,900.00 |
| 220,400.00 | 330,100.00 | 330,136.89 | 330,100.00 |
| 300,000.00 | 445,600.00 | 445,698.42 | 445,600.00 |
| 440,800.00 | 650,100.00 | 650,108.77 | 650,100.00 |
This is an unconfirmed interpretation, not proof of CPF's method. The FAQ does not specify this birthday/crediting convention or the S$100 rounding rule. An older CPF announcement describes ten years of earned interest and uses a slightly different BRS example. The match does not justify deleting six months of interest or applying a correction factor.
The main projection retains its documented earned-interest assumption for the modelled premium. No rates or payouts were changed to force a match. Download the public reference check (JSON) for all twelve calendar-start comparisons. This file contains only public example values.
Official sources used
- Contribution rates, PR stages and payroll rounding
- Account allocations and age transitions
- Monthly interest, annual crediting and transaction timing
- Official planner assumptions and conservative rounding
- 2026 self-employed MediSave rates
- Resident income-tax brackets
Additional source links for CPFIS, RSTU top-ups, property withdrawals, relief and SRS are displayed in the calculator's official-source section. They support the stated rules, not an endorsement of this project.
What the tests establish
Automated tests cover published fixtures, contribution rounding, account transfers, month-by-month cash conservation, relief caps, imports and encrypted storage. Browser checks exercise the user-facing calculation flow before release. These checks cannot prove future returns, policy stability, individual eligibility or exact agreement with a personalised CPF quotation.
CPF LIFE fallback values use male Standard Plan reference figures. Use an official CPF estimate for your own payout, especially for another plan, sex or start age.