Impact Calculator Guide for Louisiana

What this calculator does

Run this scenario in DocketMath using the Impact calculator.

DocketMath’s Impact Calculator (for Louisiana — US-LA) helps you estimate the economic “impact” of a contract breach by modeling interest on money owed after breach using a fixed statutory default.

For Louisiana, the interest component is grounded in a single, default rule for when interest is allowed after breach:

• Default rate: 10% per annum
• Trigger: “after a breach of contract”
• Exception: if the contract states a different rate, that contract rate governs

Because this is a calculator, the output is best thought of as an estimate you can use for planning, settlement discussions, or internal case review—not a promise about how a court will treat every dispute-specific issue.

When to use it

Use DocketMath’s Impact Calculator when your situation includes these core elements:

• You have a contract and a documented breach
• You want to estimate time-based money exposure after breach
• You need a quick way to test “what if” scenarios around how long the breach remained unpaid
• You’re comparing outcomes under:

  • the statutory default rate (10%/year), versus
  • a contractually specified interest rate (if your agreement sets one)

Common times this comes up:

• Demand-to-payment timing: you know when payment was due and when it was actually made (or when you’re assuming it will be made).
• Dispute staging: you’re trying to model exposure up through a specific event date (e.g., filing, hearing, or a mediation deadline).
• Settlement range planning: you want to see how sensitive the total is to the number of days interest accrues.

A gentle boundary: this guide focuses on interest math and timeline inputs. Other damage categories (e.g., consequential damages, attorneys’ fees, liquidation damages) may involve separate rules and may not be fully captured by a single calculator model.

Link: Use the calculator at /tools/impact-calculator.

Step-by-step example

Below is a worked example showing how the calculator’s inputs typically map to outputs. Adjust the dates and amounts to match your facts.

Scenario: unpaid invoice after breach

Assume:

• Principal amount owed (P): $25,000
• Breach date (B): January 10, 2026
• Assumed payment date (A): March 25, 2026
• Contract interest rate: none specified (so use the default)

The statute’s default interest rule provides:

• Interest is allowed at 10% per annum after a breach of contract, unless the contract provides a different rate.

Step 1) Compute the interest period (days)

From Jan 10, 2026 to Mar 25, 2026:

• January 10 → Jan 31: 21 days
• February: 29 days (2026 is not a leap year)
• March 1 → Mar 25: 25 days

Total = 21 + 29 + 25 = 75 days

Your calculator will effectively convert the timeline into an annualized rate prorated by the fraction of a year.

Step 2) Apply the 10% annual rate

Annual rate (r) = 0.10
Days in year (calculator default often assumes 365 days) = 365

Interest (I) ≈ P × r × (days / 365)
I ≈ $25,000 × 0.10 × (75 / 365)
I ≈ $25,000 × 0.10 × 0.205479...
I ≈ **$513.70 (approx.)

Step 3) Compute the estimated total amount

Estimated total = principal + interest
Total ≈ $25,000 + $513.70
Total ≈ **$25,513.70 (approx.)

Step 4) Interpret the output

DocketMath’s output is telling you: if the amount was unpaid from the breach date through the assumed payment date, and the interest rate defaults to 10% per year, then interest exposure over that period is approximately $513.70.

Common scenarios

Below are frequently encountered input patterns and how the calculator results generally change.

1) Contract sets a different interest rate

Inputs to watch:

• Contract interest rate field (if you have one)
• Confirm whether it’s truly interest on delinquent amounts rather than another payment-related mechanism

Result effect:

• If the contract provides a different interest rate, the calculator should use that rate instead of the statutory default 10% per annum after breach.

Legal anchor (default rule):

• Interest rate defaults to 10% per annum after breach unless the contract provides a different rate.
  (See: Cal. Civ. Code § 3289)

2) Long delay between breach and payment

If the unpaid period is extended:

• Increase in days → proportionally higher interest (prorated)
• The principal remains constant; interest accumulates over time

Quick intuition:

• Doubling the days (roughly) usually doubles the interest amount (again, prorated).

3) Partial payments

If you model partial payments:

• You may need multiple line items (e.g., interest accrues on the remaining balance after each payment date)
• Many calculators either:

  • accept multiple principal/date segments, or
  • require you to run separate scenarios and sum results

Result effect:

• Later payments generally reduce interest because the remaining principal is lower sooner.

4) No clear breach date

When breach date is uncertain:

• Interest can’t be modeled cleanly without a timeline anchor
• Use the earliest defensible date for “breach” in your internal model, or run scenarios with a range (e.g., 30-day and 60-day assumptions)

Result effect:

• Your output becomes scenario-dependent, but you gain a useful envelope for planning.

5) Contract disputes about whether money is owed

If the underlying obligation is contested, you can still use the calculator for planning, but keep outputs labeled as estimated exposure and based on your assumption of breach and amount due.

Tips for accuracy

You’ll get more reliable calculator outputs by tightening the timeline and rate inputs.

Checklist before you run the numbers

Date precision matters

Even when the difference is only a few days, interest changes:

• Short periods produce small interest amounts
• Multi-month or multi-year periods can produce material differences at 10% per annum

A practical approach:

• If you have daily records, input dates as exact days.
• If you only know month-level timing, run month-based scenarios and label them as estimates.

Rate selection: default vs contract

When contract language exists, it controls the rate. When it does not, use the statutory default:

• Default: 10% per annum after breach of contract
• Override: contract provides a different rate

Keep outputs organized for comparison

If you’re evaluating multiple settlement strategies, consider saving separate runs with:

• breach-to-offer date
• breach-to-mediation date
• breach-to-expected resolution date

This produces a time series that makes settlement discussions easier: “If resolution occurs in X days, estimated interest is about Y.”

Sources and references

Start with the primary authority for Louisiana and confirm the effective date before relying on any output. If the rule has been amended, update the inputs and rerun the calculation.

• Primary authority reference

Related reading

• Impact Calculator Guide for Alabama — Complete guide
• Impact Calculator Guide for Arizona — Complete guide
• Impact Calculator Guide for California — Complete guide