Calculate simple interest from your own figures.
Calculated in your browser. No account required. Illustrative estimate. Review the assumptions before using the result.View calculation table
How this calculation works
Interest = P × r × t
Enter the labelled inputs. Percent fields use 5 for 5%. P principal; r rate per time unit; t number of matching units.
A worked example
Principal: 1000 USD; Annual simple interest rate: 5 %; Time: 2 years. Simple interest: 100 USD.
Assumptions and limitations
P principal; r rate per time unit; t number of matching units. All monetary inputs must use one currency and time period unless conversion is explicit. Manual inputs only; no live prices or official rule tables.
Common questions
Why can my actual result differ?
P principal; r rate per time unit; t number of matching units. All monetary inputs must use one currency and time period unless conversion is explicit. Manual inputs only; no live prices or official rule tables.
Are my inputs saved?
The calculator code processes inputs within your browser and does not send them to our server or save them in browser storage. Downloads and copied summaries remain under your control.