What this calculator answers
Most retirement calculators ask whether you can stop working. Couples usually face a smaller question first: can one of us work less while the other carries on? Enter each partner's age, full-time pay, pay after cutting back and the age they plan to stop. The calculator finds the earliest age each of you could cut back, with the other working full-time, and shows what that does to the household portfolio.
A worked example
Partner 1 is 35 and takes home $5,000 a month. Partner 2 is 33 and takes home $4,000. They have $250,000 invested, spend $5,500 a month and both plan to stop at 60, which is 25 years away for one and 27 years for the other. If both work full-time until then, the portfolio reaches about $2,556,000 against $1,650,000 needed ($5,500 × 12 ÷ 4%). That is $906,000 more than required, and that margin is what lets someone cut back.
Partner 2 can cut back at 39, 6 years from now, while Partner 1 keeps working full-time to 60. Part-time pay of $1,800 a month from that point still leaves the plan funded with $57,000 to spare; one year earlier (38) it comes up $3,000 short. Partner 1 could instead cut back at 44, 9 years from now, at $2,000 a month, leaving $50,000 to spare.
In this example the partner with the lower pay can cut back sooner. Partner 2 earns 44% of the couple's combined take-home, and cutting back costs $2,200 a month against $3,000 for Partner 1, so each part-time year draws less from the savings. That is a result of these numbers, not a rule. Different ages, stop ages or part-time income can give a different answer, so enter your own.
How the math works
The household has one shared portfolio. Each year, both partners' take-home pay (full-time, part-time or none) and any pension is added, household spending is subtracted, and the balance grows at the real return: 3.88% a year from a 7% nominal return and 3% inflation. Everything is in today's dollars. The household reaches financial independence when the later partner stops, here in year 27.
The plan counts as funded when the portfolio never falls below zero along the way and, at that point, is at least the amount needed: annual spending divided by the withdrawal rate, with pension years handled as a separate phase. A larger gap shows up as the extra monthly saving that would close it. The same real-return and withdrawal logic drives the Coast FIRE calculator, and the formulas are on the methodology page. Working part-time for a few years is the idea behind Barista FIRE; this page applies it to two people at once.
What it does not model
- Taxes. Pay and spending are after tax. Withdrawals, capital gains and tax-advantaged accounts are not modelled.
- One return. The whole portfolio earns one rate. It is deterministic, so a bad first few years are not simulated. The crash test cuts today's portfolio by 30%. With it on, the default couple is still funded (about $696,000 to spare if both work to 60), but the earliest cut-backs move to 42 for Partner 2 and 47 for Partner 1.
- Life changes. Children, a move, a job loss or a windfall are not in the projection. Change the inputs and run it again.
A funded result is a projection under stated assumptions, not a guarantee that it is safe to cut back.
Frequently asked questions
Can one spouse retire early?
Yes, if the household can fund it. In the default example, setting part-time pay to $0 means Partner 2 could stop working entirely at 46, 13 years from now, while Partner 1 works full-time to 60. Partner 1 could do the same at 49. Stopping outright takes longer than cutting back to part-time, because the lost pay is larger.
Should the higher earner keep working?
It depends on the numbers, so the calculator tests both orders. In the default example the higher earner is Partner 1. Keeping Partner 1 at work lets Partner 2 cut back in 6 years; the other order takes 9 years. A different age gap, stop age or part-time income can change which order wins.
How do pensions or Social Security change the answer?
They lower the portfolio you need and add income once they start. Give Partner 1 $2,000 a month and Partner 2 $1,000 a month from age 67 and the needed portfolio falls from $1,650,000 to $935,000. The earliest cut-back moves to 36 for Partner 1 and 33 for Partner 2, which is today. Use the advanced settings to enter yours.
Does this include taxes?
No. Enter take-home pay and spending after tax. If you expect to owe tax on withdrawals, raise the spending figure to cover it. Raising household spending from $5,500 to $6,000 a month moves Partner 2's earliest cut-back from 39 to 47, so a small cushion for tax matters.