Catch-Up Contribution Calculator Formula

Understand the math behind the catch-up contribution calculator. Each variable explained with a worked example.

Use the Catch-Up Contribution Calculator

Formulas Used

Extra at Retirement

extra_at_retirement = monthly_rate > 0 ? monthly_contrib * (pow(1 + monthly_rate, num_months) - 1) / monthly_rate : monthly_contrib * num_months

Total Extra Contributed

total_extra_contributed = annual_total * years

Growth on Catch-Ups

growth_on_catchup = (monthly_rate > 0 ? monthly_contrib * (pow(1 + monthly_rate, num_months) - 1) / monthly_rate : monthly_contrib * num_months) - annual_total * years

Variables

VariableDescriptionDefault
current_ageCurrent Age(years)52
retirement_ageRetirement Age(years)65
catch_up_401k401(k) Catch-Up/Year(USD)7500
catch_up_iraIRA Catch-Up/Year(USD)1000
annual_returnExpected Return(%)7
yearsDerived value= retirement_age - current_agecalculated
annual_totalDerived value= catch_up_401k + catch_up_iracalculated
monthly_rateDerived value= annual_return / 12 / 100calculated
num_monthsDerived value= years * 12calculated
monthly_contribDerived value= annual_total / 12calculated

How It Works

Catch-Up Contributions

Workers aged 50+ can contribute beyond regular limits.

2024 Catch-Up Limits

| Account | Regular Limit | Catch-Up | Total | |---|---|---|---| | 401(k) | $23,000 | $7,500 | $30,500 | | IRA | $7,000 | $1,000 | $8,000 |

For ages 60-63, SECURE 2.0 allows an even higher 401(k) catch-up of $11,250 starting in 2025.

Worked Example

Age 52, retire at 65, $7,500 401(k) + $1,000 IRA catch-up, 7% return.

current_age = 52retirement_age = 65catch_up_401k = 7500catch_up_ira = 1000annual_return = 7
  1. 01Years = 65 - 52 = 13
  2. 02Annual catch-up = $7,500 + $1,000 = $8,500
  3. 03Total contributed = $8,500 x 13 = $110,500
  4. 04With 7% growth = ~$177,000
  5. 05Growth on catch-ups = ~$66,500

Ready to run the numbers?

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