How to use this calculator

This TSP calculator is a transparent savings projection. It combines your employee and employer or agency contribution amounts, applies a user-selected effective annual return through monthly compounding, and separates starting funds and deposits from growth. The account label provides context, not a complete simulation of plan law.

The method

Next month = current balance * (1 + monthly return) + contributions

Enter the values in the labeled fields, check the units or selected mode, and choose Calculate. The result includes the applicable working and a breakdown or visual when useful. Change an input and calculate again to update the result.

WORKED EXAMPLE

Current balance ($): 25000 Employee contribution per month ($): 500 Employer / agency contribution per month ($): 150 Assumed annual effective return (%): 5 Years of contributions: 20

TSP hypothetical balance: $330,105.36

A savings scenario, not a contribution-eligibility calculation.

Scope and limitations

No contribution limits, catch-up rules, eligibility, vesting, tax savings, fees, withdrawals, or matching eligibility are checked. Enter amounts permitted by your actual plan and verify current rules with the official provider. The result is not a guaranteed retirement benefit.

Common questions

Does this check how much I am legally allowed to contribute?

No. Annual limits and plan-specific rules are not enforced. Use current official guidance before setting contributions.

Is the employer or agency contribution automatic?

No. You enter a monthly dollar amount. The calculator does not infer a match from salary or eligibility.

References & further reading

External references provide background, not an endorsement of this implementation. See our methodology for numerical conventions and limitations.