Percentage Calculator
Quickly calculate percentages, percentage changes and what percent one number is of another.
Your inputs
How this calculator works
Use Number A and Number B for three common percentage calculations: A as a percent of B, A percent of B, and percentage change from A to B.
Last reviewed: September 2026. Estimates are for educational and planning purposes only.
How to use the result
Change one assumption at a time to compare scenarios. For example, test a lower rate, larger contribution, different term or extra payment. This makes the calculator most useful as a decision-support tool rather than a single-number answer.
Important financial decisions can depend on taxes, fees, eligibility rules, lender policies, market returns and personal circumstances that this simplified calculator does not capture.
Frequently asked questions
Is this percentage calculator free?
Yes. SumStride calculators are free to use and do not require an account.
Are the results exact?
No. Results are estimates based on the values you enter and the assumptions described on this page. Real-world fees, taxes, rates, policies and timing can differ.
Does SumStride save my inputs?
No account is required. The calculator runs in your browser; SumStride does not need your entered values to perform the calculation.