How to use the 401k calculator
Prepare the values for this calculation
Project a 401(k) balance from salary, employee contribution rate, employer match, growth rate and years. Use the formula below to check that it answers your question. Read the input units before transferring figures from a statement, measurement or dataset.
Enter and check each input
- Current 401(k) balance: enter a value at least 0. Use the unit named in the label or selected above. Do not leave this required field blank.
- Annual salary: enter a value at least 0. Use the unit named in the label or selected above. Do not leave this required field blank.
- Employee contribution (%): enter a value at least 0 and no more than 100. Use the unit named in the label or selected above. Do not leave this required field blank.
- Employer match (% of salary): enter a value at least 0 and no more than 100. Use the unit named in the label or selected above. Do not leave this required field blank.
- Annual return (%): enter a value at least -100 and no more than 100. Use the unit named in the label or selected above. Do not leave this required field blank.
- Years to contribute: enter a value at least 0 and no more than 80. Use the unit named in the label or selected above. Do not leave this required field blank.
The input table gives a complete example. Keep units and time periods consistent across related fields.
Calculate and resolve any input error
Choose Calculate after entering the values. Changes also update the answer after a short pause. If an error appears, follow its message, correct the field and calculate again. Reset restores the example values.
Interpret the answer
Check Projected 401(k) balance first. With the unchanged example inputs, it is $950,892.15. Compare the additional metrics with the primary result; each has its own label and unit.
Compare and keep a useful result
For a controlled comparison, keep every other example input unchanged and change Current 401(k) balance from 50000 to 55000. The resulting Projected 401(k) balance is $973,217.00. This illustrates the equation’s response to that input, rather than a forecast of real events.
Read the chart’s axis labels and data table. A scenario curve changes one stated input while holding the others fixed; it does not add external observations. Use Download graph to save an available chart as a PNG.
Use Copy result or Download CSV to keep the answer. Share tool shares the page address without placing your input values in the URL. Recheck inputs and assumptions before using the result for a decision.
401k Calculator formula
Monthly contributions are based on salary and match assumptions and are compounded monthly at the entered annual return.
Inputs and units
| Input | Format / range | Example |
|---|---|---|
| Current 401(k) balance | minimum 0 | 50000 |
| Annual salary | minimum 0 | 90000 |
| Employee contribution (%) | minimum 0; maximum 100 | 10 |
| Employer match (% of salary) | minimum 0; maximum 100 | 4 |
| Annual return (%) | minimum -100; maximum 100 | 6 |
| Years to contribute | minimum 0; maximum 80 | 25 |
Worked example
Using the example inputs above, the projected 401(k) balance is $950,892.15.
- Projected 401(k) balance
- $950,892.15
- Monthly modeled contributions
- $1,050.00
- Annual employee contribution
- $9,000.00
- Annual employer contribution
- $3,600.00
Results and assumptions
Employer matching rules and contribution limits vary; this model uses the simple salary percentages entered.
Fix an input or unexpected result
Current 401(k) balance is required. Enter current 401(k) balance using the format and bounds in the input table. Zero and an empty field are different: use zero only if it is allowed and represents your data.
If your answer differs from the example, choose Reset and compare every field, including selected units and options. Check percentage versus decimal entry and whether values describe the same period. Round only the final displayed answer when reproducing the formula.
If a discrepancy remains, report the calculator issue with the page address, non-sensitive example inputs, actual result, expected result and a reference for your calculation.