Best 401(k) calculators of 2026
7 401(k) calculators tested with the same case: $75,000 salary, 10% contribution, 50% employer match up to 6% of salary, $30,000 existing balance, 7% return, 30 years. Ranked on match modeling, current IRS limit awareness, catch-up handling, and freedom from lead-gen.
Want to test the assumptions used in this comparison? Open Snowballr 401(k) Calculator, enter your own figures and review the method before comparing it with the other tools below.
Open Snowballr 401(k) Calculator →Quick comparison
| Tool | Free | No signup | Match | IRS limits | Catch-up | Chart | URL share |
|---|---|---|---|---|---|---|---|
| 1. Snowballr 401(k) Calculator | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| 2. NerdWallet 401(k) Calculator | ✓ | ✓ | ✓ | ✓ | — | ✓ | — |
| 3. Bankrate 401(k) Calculator | ✓ | ✓ | ✓ | — | — | ✓ | — |
| 4. Fidelity Contribution Calculator | ✓ | — | ✓ | ✓ | ✓ | ✓ | — |
| 5. Calculator.net 401(k) Calculator | ✓ | ✓ | ✓ | — | ✓ | — | — |
| 6. SmartAsset 401(k) Calculator | ✓ | ✓ | ✓ | — | — | ✓ | — |
| 7. Vanguard Retirement Plan Tools | ✓ | ✓ | — | — | — | ✓ | — |
Detailed reviews
Snowballr 401(k) Calculator
Best overall for employer-match math + current-year IRS limits
- 100% free, no sign-up, no email collection
- Employer match modeled explicitly (percent + cap), shown as its own growth line
- Current IRS contribution limits built in, including 50+ catch-up
- Visual chart separating your money, match, and growth
- URL-shareable scenarios
- No paycheck-level tax withholding detail
- Single-account focus — no household aggregation
NerdWallet 401(k) Calculator
Best for beginners with linked explanations
- Simple salary-percent input flow
- Employer match handled cleanly
- Good educational context around the result
- Product cross-promotion
- Limited control over return assumptions
- No output sharing
Bankrate 401(k) Calculator
Best for detailed assumptions (salary growth, employer cap)
- Salary increase assumption built in
- Match percent and cap as separate fields
- Year-by-year results table
- Heavy ads
- Dated results layout
- No catch-up handling
Fidelity Contribution Calculator
Best if your 401(k) is already at Fidelity
- Ties directly to your actual plan when logged in
- Paycheck impact preview (take-home change per contribution point)
- Reliable limit updates every January
- Full value requires a Fidelity login
- Generic version is thin
- No shareable output
Calculator.net 401(k) Calculator
Best for raw configurability (fees, inflation, existing balance)
- Expense-ratio field — one of few tools modeling fees
- Inflation-adjusted output option
- Handles existing balance + match + salary growth together
- Ad-heavy, dated interface
- No visual separation of match vs contributions
- Easy to misconfigure
SmartAsset 401(k) Calculator
Best for a quick check with location-aware framing
- Clean UI
- Considers state context in retirement adequacy
- Reasonable defaults for a fast answer
- Advisor lead-gen funnel
- Limited assumption transparency
- No catch-up contributions
Vanguard Retirement Plan Tools
Best conservative second opinion from a low-cost brokerage
- Trustworthy conservative assumptions
- No sales pressure
- Pairs with Vanguard's participant data research
- 401(k)-specific tooling is limited without a plan login
- Fewer inputs than dedicated calculators
- Plain output
How we evaluated
The identical scenario went through all 7 tools: $75,000 salary, 10% employee contribution ($625/month), 50% match on the first 6% of salary ($187.50/month), $30,000 starting balance, 7% nominal return, 30 years. Correct output is roughly $1.22 million, with the employer match alone accounting for about $228,000 of it. Tools lost points for ignoring the match cap (a common source of overestimation), missing current-year IRS limits, or hiding results behind logins. Tools gained points for modeling fees, catch-up contributions, and take-home pay impact.
Primary sources
Verdict
Snowballr exposes a match-capped scenario without a login. If your plan is at Fidelity, its logged-in calculator may be a better fit because it can use plan-specific rules. Calculator.net is useful when you need explicit fee inputs. Whatever you choose, verify the employer match cap and vesting rules; a tool that applies a match to the wrong contribution base can materially overstate a long-term projection.
Frequently asked questions
What is the best free 401(k) calculator?
For most savers, a no-signup tool with explicit employer-match modeling — Snowballr or NerdWallet. If your plan is hosted at Fidelity, log in and use its native calculator, which knows your actual plan's match formula and vesting.
How much will a 401(k) grow in 30 years?
At $625/month plus a $187.50/month employer match and 7% returns, a $30,000 starting balance grows to roughly $1.22 million in 30 years. The match contributes about $228,000 of that — which is why capturing the full match is the single highest-return decision in retirement saving.
Do 401(k) calculators include the contribution limit?
Many don't — they let you enter contributions above the annual IRS employee limit without warning. Check that the tool states the current year's limit; Snowballr and Fidelity update limits each January, including the age-50+ catch-up.