Max 401(k) Contributions Calculator
Use this calculator to determine what percentage of your paycheck to contribute to max out your 401(k) contributions by the end of the year.
It calculates both pre-tax/Roth and after-tax contribution percentages and provides a paycheck-by-paycheck schedule.
1The Basics
If you received a raise, use your new salary
Age on December 31, 2026 determines catch-up eligibility
100% match up to 4% of pay
Fill in your birth year and salary
2Current Elections
Your current 401(k) election
Mega-backdoor Roth eligible
Paychecks using your current %
Auto-calculated; editable
3Year-to-Date Contributions
Total: $0.00
Total: $0.00
4Upcoming Bonusoptional if not included in YTD contributions
How it works
- Calculates optimal pre-tax and after-tax percentages to max out your 401(k)
- Accounts for catch-up contributions if you are 50+ (enhanced for ages 60-63)
- Percentages round up to the nearest 0.5%; the final paycheck adjusts to stay within limits
- In-flight paychecks use your current elections; new rates apply to remaining checks
Key Concepts
Section titled “Key Concepts”- Elective Deferrals (Pre-tax/Roth): Your direct contributions, subject to the IRS annual limit ($24,500 in 2026, higher with catch-up)
- After-tax Contributions: Additional contributions beyond your deferral limit, up to the overall IRS limit ($72,000 in 2026 base)
- Employer Match: Your employer’s matching contribution counts toward the overall limit but not the deferral limit
- Catch-up Contributions: If you’re 50+ (or 60-63 for enhanced catch-up), you can contribute more
2026 IRS Limits
Section titled “2026 IRS Limits”| Age Bracket | Deferral Limit | Overall Limit |
|---|---|---|
| Under 50 | $24,500 | $72,000 |
| 50-59 or 64+ | $32,500 | $80,000 |
| 60-63 | $35,750 | $83,250 |