Understanding Prejudgment Interest
How we calculate. Simple interest = P × r × t (r as decimal annual rate). See our methodology and accuracy policy .
Real-world scenario: A typical Prejudgment Interest case uses principal 50000 and annual rate (%) 6. Enter the same figures below to reproduce the worked path.
What is Prejudgment Interest?
Educational estimate only. Statutes may require specific rates, compounding, or day-count rules—verify jurisdiction law.
- Simple interest form (not compound)
- Confirm statutory rate
- Day-count may differ (365/360)
The Formula
Worked Example
Common Use Cases
- Demand letters: illustrative interest
- Settlement math: time-value estimates
- Teaching: simple vs compound
Pro Tips
- Check statute for rate/method
- Convert days to years carefully
- Don’t treat as court-ready without counsel
| Scenario | When to use |
|---|---|
| Percent of a number | Finding a part of a whole (tax, tip, score) |
| Percent change | Comparing old vs new values |
Limitations: Prejudgment Interest results are educational practice-management aids only—not legal advice, fee advice, or a substitute for counsel, ethics rules, or engagement letters. Confirm definitions with your firm policies and applicable professional rules.
Common mistakes
- Swapping part and whole: The denominator must be the full total, not a subset.
- Rounding too early: Carry extra decimal places through multi-step work before rounding the final percent.
- Mixing percent and decimal forms: Enter rates in the format the calculator labels expect.
When to use this calculator
- Use this page when your wording matches prejudgment interest and the form labels on screen.
- Use percent of a number for “what is X% of Y?” problems.
- Use number is what percent when you know part and whole and need the percent.
Still unsure about prejudgment interest? Start with the quick answer above, then open the linked calculator that matches your wording.
❓ Frequently Asked Questions
How do I use this prejudgment interest calculator?
For prejudgment interest, enter the values labeled on the form, then press Calculate. Compare the result to the worked example on this page.
What formula does this page use?
See the quick answer and formula box above for prejudgment interest—the same percentage calculator expression is applied to your inputs.
What if my result looks wrong?
When checking prejudgment interest, re-check part vs whole (or rate vs base), rounding, and whether percents were entered as 25 rather than 0.25 when the form expects percents.
Authoritative References
For professional conduct and practice management context, consult:
- American Bar Association — ethics and practice resources
- Law.com — legal industry reporting
- Clio Resources — practice management education