FREE CALCULATOR · LITIGATION & DAMAGES
Prejudgment Simple Interest Calculator
Estimate simple prejudgment interest for a user-entered principal, annual rate and actual date period.
Enter your numbers
Change the assumptions to match your matter.
Your calculation
Illustrative calculation based on the values you enter.
Enter your assumptions and select Calculate.
How this calculator works
Interest = principal × entered annual rate × elapsed actual days / selected day-count denominator; excludes the first date and does not compound.
Professional verification required. This is an informational worksheet, not a legal conclusion. Verify governing law, court rules, fee agreements, facts and any applicable exceptions before acting.
Questions attorneys ask
Does the calculator select the statutory interest rate?
No. Enter the governing rate and confirm whether simple interest and the selected day-count rule apply.
Does it apply variable rates or partial payments?
No. Split the period into separate calculations or use an appropriate accounting system.
Related free calculators
NEED A COMPLETE WORKFLOW?
Explore other tools and software.
This calculator is an independent planning worksheet. For complete form-preparation workflows, explore our supported Windows software and resource guides.
Litigation resources →Compare all software