Skip to content
FinToolSuite
Updated April 20, 2026 · Planning · Educational use only ·

One More Year Calculator

What does one more year actually buy you?

Calculate what one more year of work adds to your retirement portfolio — the increment to balance and to safe annual income.

What this tool does

This tool quantifies the marginal value of working one more year before retiring. Enter your current portfolio, annual contribution, expected investment return, annual expenses, and safe withdrawal rate. The calculator models what your portfolio grows to in one year, then translates that growth into extra annual retirement income using your withdrawal rate. The output shows three things: the raw balance increment, the additional safe annual income that increment supports, and the remaining distance to your retirement target. This makes the 'one more year' trade-off concrete instead of vague. Results are estimates based on your inputs and assume consistent contribution and return rates over the next twelve months. The tool is for illustration and does not account for taxes, inflation adjustments, or changes in spending patterns.


Enter Values

People also use

Formula Used
Current portfolio
Return rate (entered as a percentage value)
Annual contribution

Spotted something off?

Calculations or display — let us know.

Disclaimer

Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.

The 'one more year' syndrome is a common FIRE trap: you hit your number, but working 'just one more year' for extra cushion becomes a permanent delay. This calculator quantifies exactly what one more year adds so the decision is based on numbers, not vague cushion-seeking.

At a 1,000,000 portfolio with 50,000 annual contribution and 7% returns, one more year adds 120,000 to the balance and 4,800 to safe annual income (at 4% withdrawal). That's the real marginal value of continuing. If the question is 'is 4,800 extra a year worth another year of work?', the decision becomes concrete.

The tool doesn't tell you whether to continue working - it tells you what you're trading. For some people, 4-5 more years of 5,000-10,000 annual income increments yields net benefit. For others, reaching 95-100% of FI target is enough and the marginal extra isn't worth the lost time.

Quick example

With current portfolio value of 1,000,000 and annual contribution of 50,000 (plus annual investment return of 7% and annual retirement expenses of 40,000), the result is 120,000.00. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.

Which inputs matter most

You enter Current Portfolio Value, Annual Contribution, Annual Investment Return, Annual Retirement Expenses, and Safe Withdrawal Rate. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.

What's happening under the hood

Next year balance = current × (1 + return) + contribution. Increment = next year balance - current. Safe income increment = increment × safe withdrawal rate. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.

Using this to think, not predict

Financial plans are wrong by month six — new information arrives and reshapes the picture. The point of running projections isn't to be right in ten years; it's to be less wrong in the decision you're making this week.

What this doesn't capture

Real plans get re-run against new information every year or two. The result here is a reasonable direction, not a destination. It is a starting point for thinking, not a commitment to a specific future.

Example Scenario

One more year of £50,000 contributions at 7%% on £1,000,000 adds 120,000.00.

Inputs

Current Portfolio Value:£1,000,000
Annual Contribution:£50,000
Annual Investment Return:7%
Annual Retirement Expenses:£40,000
Safe Withdrawal Rate:4%
Expected Result120,000.00

This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.

Sources & Methodology

Methodology

The calculator computes the financial benefit of working one additional year by modeling portfolio growth over a single year. It applies the annual investment return rate to your current portfolio value, then adds your annual contribution, yielding next year's projected balance. The year-on-year increment is the difference between this future balance and your current portfolio. To estimate additional retirement income this increment could support, the calculator multiplies the increment by your safe withdrawal rate, which represents a sustainable annual drawdown percentage. The model assumes a constant annual return rate and treats contributions as occurring once per year. It does not account for investment fees, taxes, market volatility, or the timing of contributions within the year. Annual expenses are not directly modelled in the increment calculation; the safe withdrawal rate serves as the mechanism linking portfolio growth to sustainable income.

Frequently Asked Questions

How do I know when enough is enough?
When the marginal benefit of another year is smaller than the marginal cost of working that year. For most people in FI range, the answer is after 1-2 'insurance' years. Continuing 3+ years past FI usually means the work is enjoyable or the retirement isn't fully imagined - address those directly.
What's the 'sequence of returns' risk?
Retiring just before a market downturn can damage portfolio longevity even if the average return is fine. Some planners add 'one more year' specifically to de-risk this. But the mitigation is better handled through a cash buffer (2-3 years of expenses in bonds/cash) than continuing full-time work.
Does the tool count pension contributions?
No. Pension lump sums or matched contributions would add to the increment if modelled separately. Add employer pension contributions to the annual contribution input for a more complete picture.
What if I'm uncertain about retirement expenses?
Run the tool with high and low expense estimates to bracket the range. The answer changes meaningfully: 30,000 vs 50,000 annual expenses gives a 5x difference in FI target. Being confident about the number matters more than being confident about the return assumption.

Related Calculators

More Planning Calculators

Explore Other Financial Tools