One year off. Two years later to freedom.
That's not a scare line. It's the output of a new calculator on the example below, and the reason is boring arithmetic most people never run before they hand in the notice.
A year off doesn't cost you a year. It costs you the year of saving you didn't do, plus the year of spending you paid for out of the pile, plus everything that pile would have grown into. Three losses, one decision. The calendar only shows you the first one.
So I built the thing that shows all three.
What It Does
The Work-Change FI Comparison runs two paths side by side, month by month:
- Current path: you keep working, income stays where it is.
- Work-change path: one stretch of months where your income changes. Zero for a sabbatical. Half for part-time. Whatever the new job pays. Then your regular income comes back.
Same spending on both paths. Same return. Same withdrawal assumption. The only thing that changes is the income in the window you pick. Then it tells you when each path hits your FI target, the month-by-month gap between them, and the first month spending would go unfunded if the plan breaks.
No signup. No bank connection. The math runs in your browser and your numbers stay there.
The Example
Here's the full input set, because a result without its inputs is a vibe:
- First projected month: January 2027
- Capital: $150,000
- After-tax income: $6,000 / month
- Spending: $3,500 / month
- Real return: 5% a year (after inflation)
- Withdrawal assumption: 4%, so the target is 12 × $3,500 ÷ 4% = $1,050,000
- 360 months projected
Current path: reaches the target in December 2042.
Take all of 2027 off (income $0, January to December): reaches the target in December 2044. 24 months later.
At the end of that one year the work-change path is about $73,600 behind. That's $30,000 of saving that didn't happen, $42,000 of spending paid from capital, and the growth on both. And the gap doesn't close when you go back to work. Thirty years out it's about $303,000.
Now go part-time instead. Two years, 2027 and 2028, at $3,500 a month... exactly your spending. You save nothing, but you don't touch the pile either. Target reached in July 2044. 19 months later.
Twice as long away from full-time work. Five months less damage.
That's the whole point. The expensive part of a sabbatical isn't the missing paycheck. It's eating the capital. Cover your spending and the pile keeps compounding on its own while you're gone.
Run your own numbers:
What It Won't Tell You
Every number above is an output of the inputs. Change the return, the spending, the window, and it moves. That's the tool working.
It also leaves things out on purpose, and it says so on the page:
- No taxes. Every amount is already after tax.
- No benefits, pensions or required withdrawals.
- No account rules. It treats your capital as spendable. If it's locked in a 401(k) until 59½, that's on you to check.
- No market randomness. One fixed return, every month. Real markets don't do that, and a bad first year off hurts more than this shows.
- Same spending on both paths. If time off means buying your own health insurance, this example understates the cost.
It estimates. It doesn't approve your retirement and it doesn't tell you to quit. It shows you the price tag so you can decide whether it's worth it. Sometimes it is.
How It's Built
The engine is mine. Written from scratch, checked against independent recomputes, with a "Model and source" panel on the page that names the model and engine version behind every result. It's a free public calculator like the rest of the calculators, and it does count that a comparison ran (no amounts, no identity) so I can tell if anyone uses it.
Same move as the freedom number: stop guessing, get the date.
Want time off? Good. Know what it costs first. Run the comparison.