How to calculate interest in Utah

Quick takeaways

• Utah’s default post-judgment interest rule comes from Utah Code § 15-1-4:

  • If the judgment is on a lawful contract, it bears the interest agreed upon by the parties.
  • Otherwise, it bears interest at the federal postjudgment interest rate as of January 1 of each year, plus 2%.
• DocketMath (“interest” calculator) can model both paths:

  • Use an agreement rate for contract judgments.
  • Use the federal Jan 1 rate + 2% for non-contract judgments.
• Your two biggest drivers of the final number:

  • Which category applies (contract vs. any other judgment), and
  • The federal postjudgment interest rate snapshot “as of January 1” for each year in the interest period (the rate can change year to year).

Common risk: A frequent cause of incorrect results is using the current federal rate for the whole period instead of the year-by-year January 1 federal snapshots required by § 15-1-4.

Inputs you need

Before you start in DocketMath, collect the items below. The exact field names can vary slightly depending on how DocketMath structures the “interest” tool, but these inputs are what you need to apply Utah Code § 15-1-4 accurately.

A) Identify which Utah path applies (controls the formula)

Path 1 — Judgment rendered on a lawful contract

• Enter: contract agreed interest rate
• Also confirm any agreement mechanics that affect accrual (for example, whether the contract specifies a particular compounding method or timing).

Path 2 — Any other judgment

• Enter: the federal postjudgment interest rate as of January 1 for each year in the interest period
• Then apply Utah’s add-on: + 2%

B) Date and amount information (required for accrual)

Gather:

• Principal (the judgment amount)
• Start date for interest (often the judgment date, but confirm based on your case documentation)
• End date for interest (payment date, settlement date, or your cutoff date)
• Compounding method / day-count convention (only if DocketMath asks or if your contract requires a particular approach)

C) Agreement details (only for Path 1)

If the judgment is on a lawful contract, Utah requires conformity to what the parties agreed:

• Agreed interest rate (e.g., 10% per annum)
• Any agreed calculation approach the agreement specifies (e.g., simple vs. compounded, payment frequency)

How the calculation works

Utah Code § 15-1-4 provides a general/default rule with a contract exception. Based on the statute text, there isn’t a claim-type-specific sub-rule in the excerpt you referenced; instead, the statute splits judgments into two categories.

Step 1: Choose the correct Utah interest category

Use this decision framework:

Step 2: Apply the “January 1 of each year” snapshot (non-contract category)

For non-contract judgments under § 15-1-4, Utah’s statute requires a year-specific annual rate:

• For each calendar year Y in the interest period:
  Annual rate for year Y = (federal postjudgment interest rate as of Jan 1, year Y) + 2%

Because the federal rate may change between years, you typically split the period into calendar-year segments and apply the appropriate rate to each segment.

Practical workflow in DocketMath:

• If DocketMath supports multiple year/rate inputs, enter a row (or equivalent) for each year segment.
• If DocketMath only supports one rate at a time, you’ll need to run separate calculations per year segment and then sum them.

Step 3: Compute interest for each segment and add totals

At a practical level, interest accrues based on:

• Principal
• Time elapsed during the relevant segment(s)
• Applicable annual interest rate for each segment

Non-contract example (federal Jan 1 + 2% approach):

• Principal: $250,000
• Interest period: March 15, 2024 → September 10, 2025
• Because this spans two calendar years, you would apply:

  • 2024 segment (March 15–Dec 31, 2024) at (federal Jan 1, 2024 + 2%)
  • 2025 segment (Jan 1–Sept 10, 2025) at (federal Jan 1, 2025 + 2%)
• Total interest = interest from 2024 segment + interest from 2025 segment

Contract judgment example (contract agreed interest approach):
If the judgment is on a lawful contract, § 15-1-4 says the judgment bears the interest agreed upon by the parties. In DocketMath, that means:

1. Enter principal
2. Enter start and end dates
3. Enter the contract agreed interest rate
4. Mirror any agreement mechanics you can model in the tool (especially if compounding is specified)

This approach avoids the federal Jan 1 + 2% rate structure because Utah ties contract judgments to the parties’ agreed interest.

Common pitfalls

• Using the wrong category (contract vs. non-contract)

  • Example mistake: Applying federal + 2% when the judgment is on a lawful contract with an agreed interest term.
  • Fix: Confirm whether the judgment is “rendered on a lawful contract” and whether there is an agreed interest rate.

• Not using the “January 1 of each year” federal rate snapshot

  • Example mistake: Entering a single federal rate for the whole period.
  • Fix: Split by calendar year and apply the federal postjudgment interest rate as of January 1 for each year segment.

• Forgetting the statutory add-on

  • Example mistake: Entering only the federal postjudgment rate and omitting + 2%.
  • Fix: Ensure DocketMath inputs reflect (federal Jan 1 rate + 2%) for each year when using the non-contract category.

• Assuming there is a more granular rule based on claim type

  • Fix: Treat § 15-1-4 as the general/default rule described in the statute excerpt (two categories: contract exception + default).

• Day-count / compounding mismatch

  • Example mistake: The tool uses one convention (often simple interest/day-count rules) while the agreement requires another.
  • Fix: Check DocketMath’s settings (if available) and align the method with what the contract specifies.

Sources and references

• Utah Code § 15-1-4 — Interest on judgments; contract vs. non-contract rule
  Source: https://le.utah.gov/xcode/Title15/Chapter1/15-1-S4.html
  Statute text (relevant excerpt):

  “Except as otherwise provided by law, a judgment rendered on a lawful contract shall conform to the contract and shall bear the interest agreed upon by the parties; any other judgment shall bear interest at the federal postjudgment interest rate as of January 1 of each year, plus 2%.”

• Federal postjudgment interest rates (Jan 1 snapshots)
  TODO: Add the specific federal source DocketMath (or the relevant court practice) uses for the year-by-year Jan 1 rate entries you’ll input.

Next steps

1. Determine the category

   • Is the judgment “rendered on a lawful contract” (use contract agreed interest) or does it fall under “any other judgment” (use federal Jan 1 rate + 2%)?

2. Go to DocketMath’s interest calculator

   • Primary CTA: /tools/interest

3. Enter inputs carefully

   • Principal
   • Start and end dates
   • Rate inputs that match Utah Code § 15-1-4:

     • Contract path: agreed rate
     • Non-contract path: federal Jan 1 rate for each year + 2%

4. If your period spans multiple calendar years

   • Ensure the tool is using year-specific Jan 1 rates (or run segmented calculations and sum them).

Related reading

• Interest calculation in United States (Federal): judgment and statutory interest — Full how-to guide with jurisdiction-specific rules
• Why interest results differ in United States (Federal) — Troubleshooting when results differ
• Interest reference snapshot for United States (Federal) — Rule summary with authoritative citations