401k Calculator
Project your 401(k) at retirement with a realistic employer match, the 2026 IRS limit, and salary raises β then see it in today's dollars and whether you're leaving free match money on the table.
Contribute at least up to the match cap. An employer match is an instant 50β100% return β the rarest thing in investing.
$934K
Default projection: 6% of a $65k salary + 50% match, 30 yrs at 7% with 3% raises
$363K
That same balance in today's dollars after live CPI inflation β the real buying power
$46K
Free match forfeited over 30 yrs by contributing 3% instead of the full 6% cap
How to maximise your 401(k)
Capture the full match first
The single biggest 401(k) mistake is contributing below the match cap. A 50% match on 6% of salary is a guaranteed 3%-of-pay bonus. Skipping it β say contributing 3% instead of 6% β quietly costs about $46,000 over 30 years in the default scenario.
Plan in today's dollars
A near-million-dollar balance sounds like enough until inflation is accounted for. At the current CPI rate, $934,000 in 30 years buys what about $363,000 buys today. The real number is what should drive your retirement income plan.
Growth does the heavy lifting
Of the default $934,000 balance, roughly $641,000 is pure compound growth β far more than the contributions and match combined. That's only possible with decades of runway, which is why starting early beats contributing more later.
How the 401(k) projection works
Formula
Employee/yr = min(Salary Γ Your%, $24,500 IRS limit)
Match/yr = Salary Γ min(Your%, Cap%) Γ MatchRate%
Balance = Ξ£ monthly [ prev Γ (1 + r/12) + (Employee + Match)/12 ]
Salary grows by your raise % each year
Today's $ = Balance Γ· (1 + inflation)^yearsEnter your salary and contribution %
Contributions are a percentage of pay, capped at the $24,500 IRS deferral limit for 2026.
Set the employer match
The match rate (e.g. 50% = $0.50 per $1) and the cap it applies up to (e.g. 6% of salary).
Add your current balance and return
Existing savings compound alongside new contributions at your assumed annual return.
Set years and expected raises
Salary grows each year, lifting both your contributions and the match.
Read the real value and match gap
The result is deflated by live inflation, and flags any employer match you're not capturing.
Each month the balance compounds and absorbs your contribution plus the employer match. The match only applies up to the cap β so if you contribute below it, the calculator shows exactly how much free money you're forfeiting. In the default scenario, dropping from 6% to 3% leaves about $46,000 of match unclaimed over 30 years.
With the default inputs (6% of a $65,000 salary, 50% match up to 6%, 7% return, 3% raises, 30 years), the balance reaches about $934,000 β of which roughly $186,000 is your contributions, $93,000 is employer match, and $641,000 is compound growth. After live CPI inflation, that pot is worth about $363,000 in today's dollars.