401(k) calculator
Project a US 401(k) with employer match, pay rises and the 2026 contribution limits.
About the 401(k) calculator
Project a US 401(k) with employer match, pay rises and the 2026 contribution limits.
Part of SmartCalcy’s retirement tools. It runs in your browser with no account, uses your own currency and units (change them at the top of the page), and gives estimates for information only, so check official guidance before you rely on a result.
How to use the 401(k) calculator
What it calculates and when to use it
Projects a US 401(k) balance with employer match, pay rises and investment growth, and checks your contributions against the 2026 limits.
How to use it, step by step
- Enter your salary, age, retirement age and current balance.
- Enter your contribution percentage and your employer’s match.
- Enter expected salary growth, investment return and inflation.
What each input means
- Employer matches – The percentage of your contribution your employer adds, for example 50%.
- Match applies up to – The salary percentage on which the match is paid.
How to read the results
- Balance at retirement – Projected total.
- Breakdown – Starting balance, your contributions, employer match and growth.
- Income at 4% – A rough yearly withdrawal.
The formula
Each year: balance = balance × (1 + return) + (your contribution + employer match) × (1 + return ÷ 2). Match = min(your contribution, salary × match cap) × match %. Salary rises each year by the growth rate.
A worked example
A 75,000 salary, age 35, retiring at 65, 8% contribution, 50% match up to 6%, 3% raises and 6.5% return, with 30,000 saved. The balance reaches about 1,217,467, or 580,419 in today’s money.
Assumptions and limits
- Contributions are made evenly through the year.
- Limits for 2026: 24,500 employee deferral, 8,000 catch-up at 50+, 11,250 for ages 60 to 63.
- Roth and traditional tax treatment is not modelled.
Common mistakes
- Not contributing enough to get the full match.
- Forgetting that traditional 401(k) withdrawals are taxed.
Frequently asked questions
What is a catch-up contribution?
Extra contributions allowed from age 50. Ages 60 to 63 have a higher limit under SECURE 2.0.
Are the limits reached?
If your contribution is above the limit, the calculator caps it and tells you.
Dated rules: US federal figures for tax year 2026 (IRS Rev. Proc. 2025-32 and IRS notices). These calculators are estimates for planning, not tax advice.
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Details
- Your first-year contribution
- £6,000.00
- Employer match, first year
- £2,250.00
- Income at 4% a year
- £48,699a common starting withdrawal rate
- Income at 4%, today’s money
- £23,217