finance ToolUpdated 2026-09-20

Pension & Retirement Pot Calculator

Calculate how much your retirement pension could be worth by age 65 or 67 based on your current age, accumulated pot, monthly contributions, and expected investment growth.

Formula & Mathematical Methodology

Future Pot = P(1+r)ⁿ + PMT[((1+r)ⁿ - 1) ÷ r]; Monthly Drawdown = (Pot × 0.04) ÷ 12

Accumulated capital compounds monthly over your working horizon. The safe withdrawal rate (the classic 4% rule) provides an estimated annual retirement income that historically preserves capital against inflation.

Step-by-Step Worked Example

Scenario: Age 32 to 65 (33 years), $35,000 initial pot, $500/mo at 6% annual return.

1. Working horizon: 65 - 32 = 33 years (396 months).

2. Initial $35,000 compounds to: $251,845.

3. Monthly $500 contributions compound to: $619,532.

4. Total projected pension pot: $871,377.

5. Estimated sustainable monthly income (4% rule): ($871,377 × 0.04) ÷ 12 = $2,904.59 / month.

Final Calculated Result: $871,377 Projected Pot ($2,904.59/mo Drawdown)

Frequently Asked Questions

What is the 4% retirement rule?

The 4% rule is an empirical guideline from the Trinity Study suggesting retirees can withdraw 4% of their initial portfolio value in year one, adjusted for inflation each subsequent year, with a very high probability of fund survival for 30 years.