The formula
How to calculate financial independence date
The same question as the FIRE age calculator, run on monthly figures. Most people know what they save and spend per month far more precisely than per year, and a countdown in months is easier to act on than one in years.
Monthly compounding makes almost no difference to the answer — a few weeks over a twenty-year horizon — but it lets you use the numbers you actually track, and it shows progress moving between one check and the next.
Fill in the following:
- Invested today
- Saved per month
- Monthly spending in retirement
- Real return (%)
The result updates on every keystroke. The URL updates too, which makes the filled-in version easy to bookmark or send to someone else.
Worked example
A concrete run-through, using the values already in the fields:
- Invested today: 150,000
- Saved per month: 2,000
- Monthly spending in retirement: 3,000
- Real return: 5 %
That gives:
- Months to independence: 188.6 months
- Years to independence: 15.7 years
- Target portfolio: 900,000
Reading the result
Recalculate every few months rather than treating the date as fixed. A pay rise that goes entirely into savings, or a year of strong markets, moves the date more than most people expect.
Where this goes wrong. Using current spending as retirement spending without adjusting. Commuting, work clothes and pension contributions stop; healthcare, travel and time at home tend to rise. The two do not always cancel out.
Because the target is a multiple of spending and unaffected by markets, while the portfolio takes the hit. A 20% drawdown near the end of the journey can add years, which is why risk is usually reduced as the date approaches.
Real, if you are entering today's spending — and this calculator assumes you are. Using a nominal return with unadjusted spending is the most common way these projections end up years too optimistic.
The headline figure is months to independence. With 150,000 invested today, 2,000 saved per month and 3,000 monthly spending in retirement, that comes to 188.6 months. Change any field and the figure moves with it.