Set your contribution percentage right: capture the full match, see the paycheck cost
| Line | Amount |
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The 401(k) contribution percentage is the highest-leverage number in personal finance, because three multipliers stack on it: the employer match (free money at 50–100 cents per dollar), the tax deduction (Uncle Sam funds part of every contribution), and decades of compounding. This calculator makes the stack visible — showing what each percentage point actually costs your paycheck versus what lands in your account.
Default example: $85,000 salary, 8% contribution, 50% match up to 6%, 22% bracket. You contribute $6,800; the match adds $2,550; the tax break returns $1,496. Result: $9,350 invested for a take-home cost of $5,304 — $1.76 in the account per $1 of paycheck sacrifice. That ratio is why "can't afford to contribute" usually inverts to "can't afford not to."
| Common formula | Meaning | Contribute at least |
|---|---|---|
| 50% up to 6% | 50¢ per $1 on your first 6% of salary | 6% |
| 100% up to 4% | Dollar-for-dollar on first 4% | 4% |
| 100% on 3% + 50% on next 2% | Tiered | 5% |
The calculator's note flags exactly when you're below full capture — the single most common retirement mistake in America (an estimated $24B/yr of unclaimed match). One subtlety worth checking with HR: vesting (match may be forfeited if you leave within 2–6 years) and true-up provisions (front-loading contributions can accidentally forfeit match in plans without one).
Floor: whatever captures the full match. Healthy target: 15% of gross income including the match (the standard planners' benchmark). The calculator shows the paycheck cost of each point — most people are surprised how cheap the next 1% is after taxes.
Traditional deducts now (this calculator's math); Roth taxes now, withdraws tax-free later. Rule of thumb: higher bracket now than expected in retirement → Traditional; lower now (early career) → Roth. The Roth vs Traditional tool runs your numbers.
No — your deferral limit is separate. Match counts only toward the combined $70,000 ceiling, which almost nobody hits without mega-backdoor strategies.
Start where you can and automate +1% every raise — the escalator path reaches full match within a couple of years without a felt paycut. Check the calculator's true-cost line: after the tax break, 1% of salary costs ~0.78% of take-home in the 22% bracket.
Your contributions are always yours; the match follows the vesting schedule (immediate to 6-year graded). Check yours before quitting weeks short of a vesting cliff — people forfeit thousands doing exactly that.
Only if your plan has a true-up provision — otherwise maxing out by September can forfeit the match on the paychecks where you contribute nothing. Ask HR the one-word question: 'true-up?'
Yes — salary and plan details never leave your browser.
Set the percentage once, automate the escalator, and this becomes the rare financial decision that keeps paying without maintenance. The slider's verdict — full match captured — is worth more than almost any investment-picking you'll ever do.