401(k), SIMPLE IRA & IRA Contribution Basics
Elective deferrals, employer match formulas, SIMPLE IRA, IRS limits, and Roth IRA MAGI phase-outs in plain language.
By Greg, Editor at Finance Maxx. Published · Updated
The IRA contribution calculator is the same tool as the workplace 401(k) / SIMPLE IRA calculator — switch Account type to IRA for Traditional or Roth IRA limits, catch-up, and Roth MAGI phase-outs. SEP IRA employer contributions are not modeled; use IRA mode for a personal IRA or 401(k) / SIMPLE for workplace plans.
Workplace plans let you defer salary into a traditional or Roth 401(k). Many employers match a portion of what you put in — but only under a specific match formula. The same tool also models SIMPLE IRA (a smaller-employer workplace plan) and personal Traditional/Roth IRAs with their own lower limits.
Match formulas (401(k) mode)
Employers rarely match “everything you put in.” Two common patterns:
- Classic 3% + 2% (default in the calculator): 100% match on the first 3% of salary you defer, then 50% on the next 2%. If you earn $100,000 and defer 10%, the employer puts in 3% + 1% = $4,000 (max when you defer 5%+).
- Simple % of pay: 100% of your deferrals up to a single cap (for example 3% of salary — common on SIMPLE IRAs). Deferring more than the cap does not increase the match.
The 401(k) & IRA contribution calculator applies these formulas, caps employee deferrals at common IRS limits for the year, and can project simple growth of this year’s contributions.
Limits (traditional + Roth 401(k) share one bucket)
| 2025 | 2026 | |
|---|---|---|
| Employee elective deferral (under 50) | $23,500 | $24,500 |
| Catch-up (50+, standard) | $7,500 | $8,000 |
| Super catch-up (60–63, if plan allows) | $11,250 | $11,250 |
| Overall employee + employer (415(c)) | $70,000 | $72,000 |
Roth 401(k) deferrals count against the same elective limit as traditional 401(k).
SIMPLE IRA (separate workplace path)
SIMPLE IRA plans use lower employee limits and a different catch-up schedule. In the calculator, pick SIMPLE IRA under account type — match defaults to a flat 3% of pay style formula (you can still change the “match up to” percent). Super catch-up ages 60–63 can apply when the plan allows; confirm with plan docs.
| 2025 | 2026 | |
|---|---|---|
| Employee salary reduction (standard plans) | $16,500 | $17,000 |
| Catch-up (50+, standard) | $3,500 | $4,000 |
| Super catch-up (60–63, if plan allows) | $5,250 | $5,250 |
Some ≤25-employee plans may allow higher employee limits under IRS rules — this model uses the standard (not elevated) limits.
IRA mode and Roth MAGI phase-outs
Toggle to IRA for personal traditional or Roth IRA limits (for example $7,500 under 50 in 2026, plus catch-up if 50+). Contributions also cannot exceed taxable compensation. Personal IRAs do not use employer match or 60–63 super catch-up.
For Roth IRA, direct contributions also depend on modified AGI and filing status. The calculator applies IRS phase-out ranges for 2025 and 2026 (full contribution below the start of the range, reduced through the range, $0 at or above the end). Backdoor Roth is not modeled.
Confirm every figure against IRS COLA notices and your plan documents.
2026 limits in one place. Notice 2025-67 / IR-2025-111 set elective deferrals at $24,500, IRA at $7,500, catch-up and ages 60–63 super catch-up, plus Roth MAGI phase-outs. Open-enrollment comparison and leftover-room example: 2026 401(k) & IRA contribution limits.
Try it
Enter salary and raise deferral until you capture the full match (about 5% under the classic 3% + 2% formula), then decide whether to go further toward the annual limit. Switch to SIMPLE IRA or IRA + Roth and enter MAGI to see how limits and phase-outs change.
Order of operations
- Defer enough to capture the full match (about 5% of pay under the classic 3% + 2% formula).
- If you have an HDHP, fill HSA room.
- Then IRA (watch Roth MAGI), then more 401(k) toward the elective limit, then taxable accounts.
Tax timing (Roth vs traditional) is a separate compare after the match is captured: Roth vs traditional. Tables on this page match This year — retirement.