A percentage field is an easy way to specify 401(k) contributions — until the percentage times a real salary quietly exceeds what the IRS actually allows.
401k contribution limit 2026 calculator, checked automatically
The 2026 limit is $24,500 for regular employee deferrals. Enter 10% of a $500,000 salary and that's $50,000 — double the limit. This tool catches it, shows a clear warning with both numbers, and caps the actual contribution used in the projection at the real limit instead of silently running the math on an impossible number.
401k catch up contribution calculator, age-aware
The limit isn't flat across ages. 50 and older adds an $8,000 catch-up (limit: $32,500). Ages 60 through 63 get a larger $11,250 super catch-up on plans that allow it (limit: $35,750) — this tool applies the correct tier automatically based on the age you enter.
401k calculator with employer match, capped correctly
Employer match is modeled as a percentage of your contribution, capped at a percentage of salary — the way most real 401(k) plans structure it (e.g., "50% match up to 6% of salary") — and it's factored into the growth projection alongside your own contribution.
