Retirement Spending Runway Calculator: a practical guide
Would my savings cover spending if losses arrive early?
See whether savings fund a chosen spending plan, then reverse the same returns to uncover why early losses matter.
By VolatileShares · Example version 1 · Updated . Hypothetical inputs, not financial recommendations or live company data.
A worked example, in plain English
The idea in 10 seconds: Taking money out after an early loss can hurt more than the same loss later.
Savings do not cover every planned withdrawal.
Entered return order: first spending gap in year 11. Reversed order: first spending gap in year 15. Neither result proves lifetime funding.
Funding the chosen years is not a promise the money lasts for life.
- Ending savings
- $0.00
- Years before first spending gap
- 10
- Total unfunded spending in tested years
- $1,532,980.32
Walk me through the full calculation
$600,000.00 starts the plan, covering an initial $48,000.00 yearly gap after other income. The first spending shortfall occurs in year 11. Ending savings are $0.00, with $1,532,980.32 of planned spending unfunded across the horizon.
Reversing exactly the same annual returns leaves $0.00 and $1,305,852.62 of unfunded spending. Selling from a smaller balance after early losses can change what remains, even when the return list has the same average. Filled years use 5%; spending and other income rise together at 2.5%. This is a deterministic stress example, not a retirement recommendation.
No sample success probability or safe withdrawal rate is calculated. Unfunded spending is the sum of nominal-dollar gaps across years, not today's-dollar buying power.
Inputs used for this example
These are the calculator's example defaults, not suggested amounts or rates. Market calculators initially display USD. Change currency in the toolbar without creating a personal profile. Under optional Location & display settings, choose an example country for its currency and available historical CPI. Review any example household size and rent assumption before explicitly applying local assumptions: matching unedited budget/inflation fields change, while edited or restored inputs are kept. Lifestyle budgets are fictional examples, not measured national averages. Local tax, pension and borrowing links are guidance, not personal calculations. Switching currency alone does not change percentages, ages or share counts.
- Savings available at the start (USD)
- 600,000
- Monthly spending in today's USD
- 4,000
- Other monthly income in today's USD
- 0
- Yearly return for unspecified years (%)
- 5
- Yearly investment fee (%)
- 0.5
- Yearly spending and income rise (%)
- 2.5
- How many years?
- 30
- Optional early yearly returns, in order (%)
- -20, -10, 15, 12, 8
Work backwards from your goal
What starting savings cover this monthly lifestyle in both return orders?
Start with a monthly budget to find savings that cover both return orders.
Choose Work backwards, enter your target and the few essential inputs, then choose Calculate my goal. The answer is checked with the same forward calculation and applied in one step. Example assumptions are disclosed under More options. Expand Calculation details & tools only if you want more detail. Impossible or out-of-range goals show an error instead of invented numbers. Long numbers display commas while editing; calculations and saved snapshots keep the original precision.
Checks the full entered horizon with both the original and reversed return lists. It is not a lifetime guarantee.
Return to the interactive calculator above →How the calculation works
At each year-start withdraw min(balance, annual uncovered spending). Apply that year's return, then the annual fee. Spending and other income rise with inflation. Repeat with the exact same full return list in reverse order; report spending gaps, not a success probability.
What this cannot tell you
Deterministic examples, not Monte Carlo probabilities, historical returns or a safe-withdrawal recommendation. Withdrawals occur at year-start; fees are applied after returns. Other income and expenses rise at the same constant inflation rate. No taxes, benefits rules, borrowing or extra deposits. A funded horizon cannot prove lifetime sustainability.
Changing an assumption changes the example, not the future. Verify source dates and actual product, tax and lending terms before relying on any result. These tools do not replace appropriately qualified advice.
Withdrawals make return order matter
From $100, withdraw $10 at each year-start. Returns of -50% then +100% leave $70, while the same returns reversed leave $85, without fees or inflation. The average return alone hides the different outcomes.
Illustrative arithmetic, not market evidence or a promise of returns.
Keep a useful starting point
In the interactive calculator, compare different assumptions or explicitly save a named snapshot to My browser notebook. Saving is optional and browser-only, not an account or cloud backup. Revisit it on the same browser profile; restoring never refreshes prices or assumptions.