Retirement pot and drawdown projection
Project a retirement pot from contributions, returns, charges and inflation, then see how long an income lasts, with a chart, yearly table and lower-returns check.
A clear answer. Here’s how.
The pot grows at the return you enter less the annual charges, treated as one effective annual rate i = return − charges. Contributions are paid at the end of each month (or year) and can rise by a fixed percentage each year; with monthly contributions the monthly rate is (1 + i)^(1/12) − 1, so twelve months compound to exactly i. Retirement is worked out in whole years in today’s money, using the real return r = (1 + i) / (1 + inflation) − 1, and income that rises with inflation. Income is taken at the start of each year (the cautious choice) or at the end. There are three ways to take it: a level real income that you choose; the highest level real income that uses the pot up exactly when the period ends (with no other income and income taken at year end this is pot × r / (1 − (1 + r)^−N) for N years, divided by (1 + r) for start-of-year income, and pot ÷ N when r is zero); or a fixed percentage of the pot left each year, which never runs out but pays a varying income. Other income, such as a state pension, is a plain amount in today’s money that starts in the retirement year you choose and reduces what the pot must pay, so the income you choose and the highest level income both mean total income, with the pot paying whatever other income does not cover. The "returns 2 points lower" figures repeat the whole projection with the return cut by two percentage points: one deterministic scenario, not a simulation or a range. Tax, other fees, annuity purchase, investment risk, the order of returns and changing inflation are not modelled. It is a projection with constant rates, not a forecast or financial advice.
How this is checked
5 reference checks passed These 5 cases were run when this page was built, on 20 October 2026, and all reproduce within the stated tolerance. The same cases are part of the automated tests that run on every change to Toolmoz. Engine version 1.
See the checks and where each expected answer comes from
Case 1
- Inputs
- Pot today 50000Contribution each period 6000Contributions are paid yearlyContributions rise each year by (%) 2Investment return (% a year, before charges) 5Annual charges (% of the pot) 0.75Inflation (% a year) 2.5Years of saving before retirement 25Years of retirement to project 25Income in retirement exhaustIncome is taken endOther yearly income, such as a state pension (today’s money) 0
- Expected, and what Toolmoz gave
- Pot at retirement (nominal) expected 458909.38993975654, Toolmoz 458909.3899397564Pot at retirement (today’s money) expected 247531.4063434144, Toolmoz 247531.40634341486Total contributions expected 192181.79833941898, Toolmoz 192181.798339419Highest level income for the whole retirement (today’s money a year) expected 12247.222024215871, Toolmoz 12247.222024215896Pot at retirement, returns 2 points lower (today’s money) expected 181075.63626335573, Toolmoz 181075.63626335602
- Where the expected answer comes from
- Exact Python Fraction arithmetic (independent script). Net rate i = 5% - 0.75% = 17/400. Yearly contributions of 6,000 rising 2% a year: FV = P0 (1 + i)^25 + C ((1 + i)^25 - 1.02^25) / (i - 0.02) = 458,909.39, the same as the year-by-year recursion. In today’s money that is 458,909.39 / 1.025^25 = 247,531.41. Real return r = (1 + i) / 1.025 - 1 = 7/410, so the level income that uses the pot up in 25 years, taken at year end, is 247,531.41 x r / (1 - (1 + r)^-25) = 12,247.22. Contributions total 192,181.80. With a 3% return the same script gives a pot of 181,075.64 in today’s money
- Allowed difference
- ±1e-9 relative
Case 2
- Inputs
- Pot today 30000Contribution each period 400Contributions are paid monthlyContributions rise each year by (%) 2Investment return (% a year, before charges) 5Annual charges (% of the pot) 0.75Inflation (% a year) 2.5Years of saving before retirement 30
- Expected, and what Toolmoz gave
- Pot at retirement (nominal) expected 468652.6335245853, Toolmoz 468652.6335245748Pot at retirement (today’s money) expected 223426.71492364389, Toolmoz 223426.7149236395Total contributions expected 194726.7801848049, Toolmoz 194726.780184805
- Where the expected answer comes from
- Independent Python Decimal script (60 digits). Monthly rate j = 1.0425^(1/12) - 1. The closed form FV = P0 (1 + i)^30 + C (i / j) ((1 + i)^30 - 1.02^30) / (i - 0.02) with P0 = 30,000, C = 400 and i = 0.0425 equals the month-by-month sum of 360 deposits that rise 2% each year: 468,652.63. Divided by 1.025^30 that is 223,426.71. Contributions are 400 x 12 x the sum of 1.02^(y-1) for y = 1 to 30 = 194,726.78
- Allowed difference
- ±1e-9 relative
Case 3
- Inputs
- Pot today 100000Investment return (% a year, before charges) 4Annual charges (% of the pot) 0Inflation (% a year) 0Years of saving before retirement 0Years of retirement to project 25Income in retirement exhaustIncome is taken endOther yearly income, such as a state pension (today’s money) 0
- Expected, and what Toolmoz gave
- Highest level income for the whole retirement (today’s money a year) expected 6401.1962786454615, Toolmoz 6401.196278645464
- Where the expected answer comes from
- Level annuity payout: income = P r / (1 - (1 + r)^-N) with P = 100,000, r = 4% and N = 25. The annuity factor (1 - 1.04^-25) / 0.04 = 15.62207994, so income = 100,000 / 15.62207994 = 6,401.196 (independent Python Decimal and Fraction calculation)
- Allowed difference
- ±1e-9 relative
Case 4
- Inputs
- Pot today 10000Contribution each period 100Contributions are paid monthlyContributions rise each year by (%) 0Investment return (% a year, before charges) 0Annual charges (% of the pot) 0Inflation (% a year) 0Years of saving before retirement 20Years of retirement to project 20Income in retirement exhaustOther yearly income, such as a state pension (today’s money) 0
- Expected, and what Toolmoz gave
- Pot at retirement (nominal) expected 34000, Toolmoz 34000Total contributions expected 24000, Toolmoz 24000Growth after charges expected 0, Toolmoz 0Highest level income for the whole retirement (today’s money a year) expected 1700, Toolmoz 1700
- Where the expected answer comes from
- With no return, no charges and no inflation the pot is only what goes in: 10,000 + 100 x 12 x 20 = 34,000, contributions are 24,000, growth is 0, and the income that uses it up evenly over 20 years is 34,000 / 20 = 1,700 (hand arithmetic)
- Allowed difference
- ±1e-9
Case 5
- Inputs
- Pot today 100000Investment return (% a year, before charges) 0Annual charges (% of the pot) 0Inflation (% a year) 0Years of saving before retirement 0Years of retirement to project 20Income in retirement levelTotal yearly income wanted (today’s money) 5000Income is taken endOther yearly income, such as a state pension (today’s money) 0
- Expected, and what Toolmoz gave
- Pot runs out expected Lasts exactly 20 years, Toolmoz Lasts exactly 20 yearsPot left after retirement (today’s money) expected 0, Toolmoz 0Total taken from the pot (today’s money) expected 100000, Toolmoz 100000
- Where the expected answer comes from
- Taking 5,000 a year from 100,000 with no growth uses the pot up in exactly 100,000 / 5,000 = 20 years, so every one of the 20 years is paid in full and nothing is left (hand arithmetic; 5,001 a year would fail in year 20)
- Allowed difference
- ±1e-9
What this shows: the engine reproduces independently worked values for these cases. It does not prove every possible input is right. To test an answer you were given, see how to check a number; to see what is and is not checked across Toolmoz, see the accuracy ledger.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Currency symbol (labels only)
- £ pounds
- Pot today
- 30000
- Contribution each period
- 400
- Contributions are paid
- Monthly
- Contributions rise each year by (%)
- 2
- Investment return (% a year, before charges)
- 5
- Annual charges (% of the pot)
- 0.75
- Inflation (% a year)
- 2.5
- Years of saving before retirement
- 30
- Years of retirement to project
- 25
- Income in retirement
- A level income I choose (today’s money, rising with inflation)
- Total yearly income wanted (today’s money)
- 20000
- Income is taken
- At the start of each year
- Other yearly income, such as a state pension (today’s money)
- 9000
- Other income starts in retirement year
- 6
Example result
| Year | Phase | Contributions in the year (nominal) | Income from the pot (today’s money) | Other income (today’s money) | Pot at year end (nominal) | Pot at year end (today’s money) | Pot at year end, returns 2 points lower (today’s money) |
|---|---|---|---|---|---|---|---|
| 0 | Start | 30,000 | 30,000 | 30,000 | |||
| 1 | Saving | 4,800 | 36,167.7973656 | 35,285.6559665 | 34,657.8547676 | ||
| 2 | Saving | 4,896 | 42,695.5820666 | 40,638.2696648 | 39,281.2707407 | ||
| 3 | Saving | 4,993.92 | 49,600.6106836 | 46,059.0978621 | 43,870.4444928 | ||
| 4 | Saving | 5,093.7984 | 56,900.9123445 | 51,549.4182282 | 48,425.5715687 |
You take £20,000 a year in today’s money, helped by £9,000 a year of other income from retirement year 6; income is taken at the start of each year. Contributions of £194,727 and growth of £243,926 make up the pot. If returns were 2 points lower the pot at retirement would be £155,525 in today’s money and the pot would run out in year 10 of retirement. A projection with constant rates, not a forecast or advice: real returns, inflation and charges vary.