How Much More Should I Contribute?
How much difference does raising my monthly investment contribution actually make?
Compare your current monthly contribution with a higher (or lower) one. The model shows how much of the difference comes from the extra money itself and how much from compounding over time.
Current balance and time horizon.
Scenario A and Scenario B.
Value, growth and catch-up years.
Prepared by the Wealthton Editorial Team under our editorial policy. Last reviewed: October 5, 2026.
What this decision compares
Both scenarios start from the same balance, return and time horizon and differ only in the monthly contribution. Growth uses monthly compounding with contributions at the end of each month — the same method as the Wealthton Monthly Investment Calculator — so results can be cross-checked there.
How to read the result
Compare the extra amount you contribute with the extra ending value. Over long horizons the gap grows much faster than the extra contributions because earlier dollars compound for longer. The catch-up figure shows how many additional years the lower contribution would need to reach the same value, which is often a more intuitive way to see the cost of waiting.
What the model does not include
It does not model employer matching, tax treatment of different account types, contribution limits, fees, inflation, salary growth, or variable market returns. The 4% income figure is a rough illustration of sustainable withdrawals, not a retirement income guarantee. For withdrawals and retirement age, use the Retirement Calculator.
Change one thing
Under the results, each card changes a single input and keeps everything else fixed, then shows how far the main result moves. Use Apply this change to adopt it, or Pin as baseline first so the page lists what you changed and the effect. Copy shareable link saves only the inputs in the link (after the #), which is never sent to our server.
Your inputs vs calculated results
Every number in the left-hand form is an assumption you control. The verdict, scenario cards and the results-over-time table are calculated from those inputs only. Fixed model assumptions are listed under the results so you can see exactly what is not coming from you. Inputs outside a sensible range are limited and flagged rather than silently changed.
Check the numbers elsewhere
For more detail on the same scenario, use the Monthly Investment Calculator and the Retirement Calculator. For background on the trade-offs, read the Retirement planning guide and Starting at 25 vs 35. Our calculator methodology explains how Wealthton models are built and checked.
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Pay Off Debt or Invest? — I have extra money each month. Should it go to my debt or into investments?
How Big Should My Emergency Fund Be? — How many months of expenses should I keep in cash, and how long will it take to get there?
This is an educational scenario model, not personalized financial advice. Results depend entirely on the assumptions entered. See our disclosures, or contact us if you spot an error.