Financial independence: the savings rate is the whole game
The time to financial independence depends far more on the proportion of income you save than on the amount you earn, because saving more both builds the pot faster and lowers the target.
What this calculator does
- Calculates the pot needed to sustain your desired spending at your chosen withdrawal rate.
- Estimates how many years it takes to reach it at your current savings rate.
- Reports leaner and more generous variants of the target for context.
- Shows your current savings rate and progress towards the target.
How the calculation works
The target — often called the FIRE number — is your desired annual spending divided by the withdrawal rate you consider sustainable. At 4% that is twenty-five times your spending. The projection then compounds your current invested assets and your annual savings forward until they reach it. What makes savings rate so dominant is that it works on both sides of the equation at once: saving a larger share of your income means more going in each year, and it also means you are living on less, which lowers the target you are aiming at. Someone saving half their income is filling a smaller bucket faster from both directions, which is why the relationship between savings rate and years to independence is steep rather than linear. Income matters, but only through the savings rate it makes possible — a high earner who spends everything is no closer than a modest earner who saves half.
The rule
Target = desired annual spending ÷ withdrawal rate. Years to reach it = the time for current assets plus annual savings, compounded at the expected return, to equal the target.
Step by step
- Subtract current annual spending from net income to give annual savings.
- Divide desired retirement spending by the withdrawal rate to give the target.
- Compound current invested assets and annual savings forward at the expected return.
- Find the year the projection reaches the target.
Worked example
A 30-year-old taking home £45,000, spending £25,000, with £20,000 invested, targeting £25,000 of spending in retirement at a 4% withdrawal rate and 5% returns.
What was entered
| Current age | 30 |
|---|---|
| Annual take-home pay | £45,000 |
| Current annual living expenses | £25,000 |
| Current invested assets | £20,000 |
| Desired retirement spending | £25,000 |
| Safe withdrawal rate | 4% |
| Investment return rate | 5% |
The arithmetic
- Annual savings are £45,000 − £25,000 = £20,000, a savings rate of 44.4%.
- The target is £25,000 ÷ 4% = £625,000, which is twenty-five times the desired spending.
- £20,000 of existing assets is only 3.2% of the way there.
- Compounding £20,000 plus £20,000 a year at 5% reaches the target in about 17.9 years.
- That puts financial independence at roughly age 48.
- Living on £18,750 instead would cut the target to £468,750 and reach it appreciably sooner — from both directions at once.
What the calculator returns
| Target pot | £625,000.00 |
|---|---|
| Years to reach it | 17.92 |
| Age reached | 47.92 |
| Current savings rate | 44.44% |
| Annual savings | £20,000.00 |
Key assumptions
- Income, spending and savings all stay flat in real terms.
- Returns are steady at the rate entered, with no volatility.
- The withdrawal rate is treated as sustainable indefinitely.
- All savings are invested rather than held in cash.
Limitations
- Withdrawal-rate rules of thumb come largely from historical US market data over specific periods, and are not a guarantee for a UK investor over a different future.
- Sequence of returns risk is not modelled: a poor first decade of returns can exhaust a portfolio that the average return suggested was safe.
- Retiring well before pension age means bridging years before pensions and the State Pension become accessible — and the normal minimum pension age rises to 57 in April 2028.
- Tax on investment returns outside an ISA or pension is not modelled, and wrapper choice materially changes the outcome.
- Life is not flat. Children, health, career changes and inflation all move spending in ways a constant figure cannot capture.
- This is a projection, not advice.
Common questions
Why does the savings rate matter more than income?
Where does twenty-five times spending come from?
Can I access my pension at 48?
Is a 4% withdrawal rate safe over forty years?
Related calculators
- Safe Withdrawal Rate Calculator — Test the withdrawal rate this target depends on against different retirement lengths.
- Monte Carlo Investment Simulator — See the range of outcomes rather than a single average path.
- Stocks & Shares ISA Growth Calculator — An ISA is the usual wrapper for the years before a pension can be touched.
- Retirement Target Calculator — Model the pension side of the same plan, including the State Pension.
Official sources
Every figure in this guide was checked against the sources below. Where a source could not confirm a figure, it is marked as requiring verification rather than presented as settled.
- Pension Wise: free pension guidance — MoneyHelperFree impartial guidance on pension options, available from age 50
- Personal pensions: when you can take your pension — GOV.UKPension savings are not normally accessible before the normal minimum pension age
- The new State Pension: what you'll get — GOV.UKFull new State Pension £241.30 a week; 35 qualifying years for the full rate where the record began after April 2016