Calculators
Three simple illustrations of how money behaves over long stretches of time, each building on the last. Change any number and everything updates.
- Where your income goes: taxes, saving, and what's left to spend, plus pre-tax vs. Roth and Roth vs. taxable
- Your savings rate: why how much you save matters most
- The long game: what time and returns do to your plan
Also: should you pay down debt or invest?
Your numbers are saved in this browser only, so they're still here if you refresh or come back later.
1. Where your income goes
What goes to taxes, what you save, and what's left to spend, and how saving through a 401(k) and HSA lowers your taxes. Money saved pre-tax costs you less than a dollar of spending money for every dollar saved. Roth accounts work the other way: no tax break now, but tax-free growth and withdrawals later.
Your actual spending?
Upload a transactions export (CSV) from Monarch Money, Mint, Copilot, YNAB or your bank to see where your money actually goes each month, next to what your plan above leaves you to spend.
Your file stays on this device: it's read in your browser, never uploaded, and forgotten when you leave the page. Only each transaction's date, amount and category are used; merchant names, accounts and notes are ignored.
Your accounts or all taxable?
Your saving plan above, next to the simplest alternative: skip the 401(k), HSA and Roth accounts and invest in a regular taxable account instead, keeping the same amount to spend each month. Without the pre-tax accounts you'd pay more tax now, so there's less to invest.
Pre-tax or Roth?
Pre-tax saves you tax now; Roth saves you tax later. Which comes out ahead depends only on your tax rate today versus your tax rate when you take the money out.
Many people are in a lower bracket once work is optional, which favors pre-tax. But that assumes tax rates don't rise, and with federal debt where it is, that's a big assumption. It's why many people keep some of each.
Roth or taxable?
Money you'd invest after tax anyway can go into a mega backdoor Roth or a regular taxable account. Both start with the same dollars. The taxable account pays tax on dividends every year and on its gains when you sell; the Roth never does.
SEP IRA or Solo 401(k)?
Both let your business put in up to 20% of your net self-employment income (25% of an S corp salary), pre-tax. A Solo 401(k) adds your own 401(k) contributions, pre-tax or Roth, and, if the plan allows after-tax money, a mega backdoor Roth on top, up to $72,000 a year in all. A SEP IRA is business money only, all pre-tax. For an S corp, both plans count only your salary as pay: distributions don't count toward either.
2. Your savings rate
How much you keep matters more than almost anything else. Here's your savings rate from above next to 10%, 20% and 30% of the same income: invested until work becomes optional, then drawn down to the age you plan for. Everything is in today's dollars.
Once work is optional, your savings keep growing while you draw them down, and withdrawals rise with inflation. Self-employed income (consulting, a small business, part-time work) is money you don't need from savings. Slide "Plan to age" to see what living longer does. Nobody knows future inflation; 3% is roughly the long-run U.S. average.
3. The long game
Your plan from steps 1 and 2, at your return and at 4% to 10% for comparison. Small differences in return compound into big differences over time.
Also: should you pay down debt or invest?
You have some extra money each month. Put it toward the debt first, or invest it while paying only the minimum? Either way, once the debt is gone, the whole payment gets invested.
For illustration only, not financial or tax advice. Returns are never guaranteed. See all assumptions.