Impact Calculator Guide for Arizona

What this calculator does

DocketMath’s Arizona Impact Calculator (impact-calculator) computes interest on damages using the governing rule in A.R.S. § 44-1201.

Start with the statute text that controls the default approach:

“Interest is allowed at the rate of 10 percent per annum on damages when the amount is made certain by agreement or by law.” — A.R.S. § 44-1201 (Arizona)

In practical terms, the calculator applies this structure:

• Interest rate: 10% per year (10% per annum)
• Interest base: the damages amount (the principal)
• Timing concept: interest is only allowed when the damages amount is “made certain” by agreement or law
• Method: calculate interest over the relevant period based on the dates you enter, and show the total(s)

What “made certain” means for calculator inputs

This calculator is intentionally set up around the statute’s condition: the damages amount must be certain (by agreement or law) before interest runs. Different facts can affect when certainty occurs, but the tool can only calculate from the inputs you provide.

To avoid surprises, DocketMath’s workflow assumes you will supply:

• the damages/principal amount
• the start date when the amount became certain (by agreement or by law)
• the end date you want the calculation through
• optionally, a day-count convention (if the tool offers one) to keep internal period math consistent

Default rule (no claim-type-specific sub-rule found)

No claim-type-specific sub-rule was found beyond the statute’s general language. So this tool treats A.R.S. § 44-1201 as the default governing rule:

• 10% per annum on damages
• once the amount is made certain by agreement or law

When to use it

Use the DocketMath Arizona Impact Calculator when you want a statute-based interest estimate grounded in A.R.S. § 44-1201.

It’s especially helpful for:

• comparing how interest changes as the certainty start date changes
• modeling the impact of different end dates (e.g., filing date, judgment date, or a chosen cutoff)
• estimating interest exposure alongside the principal damages figure
• creating a consistent calculation narrative for internal review

Key trigger condition: certainty by agreement or by law

The statute limits when interest is allowed:

• By agreement: the parties fix or make the damages amount certain through a contract term, settlement term, stipulation, or similar agreed certainty.
• By law: the damages amount becomes certain through a legal determination (for example, a verdict/judgment that fixes the damages number).

Common “when” choices people model

In practice, parties often disagree on the “made certain” date. The calculator is useful for testing different theories of that timeline, such as:

• Start date on settlement date (if the settlement makes damages certain)
• Start date on judgment date (if the judgment fixes the damages)
• Start date on an order (if an order fixes the damages amount)

Step-by-step example

Below is a concrete walkthrough using the calculator logic under A.R.S. § 44-1201 (10% per annum). Use the tool at /tools/impact-calculator.

Example fact pattern (modeled for calculation)

Assume:

• Damages (principal): $50,000
• Interest start date (certainty made certain by agreement or law): March 1, 2023
• Interest end date (calculation through): December 31, 2023
• Rate: 10% per annum under A.R.S. § 44-1201

In the calculator, you would input the principal and the dates, and it would compute interest over the period.

Step 1: Enter the principal amount

• Damages amount: $50,000

This is the base for calculating interest at 10% per year.

Step 2: Enter the interest start date

• Start date: 2023-03-01

This is the date you treat as the point when the damages became certain by agreement or by law, matching the statutory condition in A.R.S. § 44-1201.

Step 3: Enter the interest end date

• End date: 2023-12-31

The calculator uses the days between the two dates to measure the interest period.

Step 4: Confirm day-count behavior (if the tool offers it)

Some calculators support options such as:

• actual/365
• actual/360
• simplified 365-day logic

If DocketMath’s UI includes a day-count option, choose the one that best matches your internal tracking so comparisons remain consistent.

Step 5: Review the outputs

You should expect outputs like:

• Total interest over the selected period at 10% per annum
• Principal + interest totals (if displayed)
• a summary that ties the interest to your rate and date range

Relationship check (even before you compute):

• longer periods → higher interest
• higher damages amount → higher interest
• later start date → lower interest

Common scenarios

Arizona interest calculations often turn on which date counts as “made certain,” because A.R.S. § 44-1201 requires certainty by agreement or by law. Use the calculator to test those competing timeline theories.

Scenario A: Certainty comes from a settlement agreement

Typical approach:

• Settlement terms state a specific damages number (or a formula that makes damages certain).
• Interest starts on the date the agreement made damages certain.

Calculator inputs to model:

• Principal = settlement damages amount
• Start date = settlement/effective date that made the amount certain
• End date = your chosen cutoff for calculation

Result direction:

• later certainty date → less interest
• larger damages figure → more interest

Scenario B: Certainty comes from a judgment or verdict

Typical approach:

• The court’s determination fixes the damages amount.
• Interest starts when damages became certain by law.

Calculator inputs to model:

• Principal = the damages figure fixed by the judgment/verdict
• Start date = date damages became certain under the judgment record
• End date = your calculation cutoff

Result direction:

• earlier supported certainty date → higher interest
• later supported certainty date → lower interest

Scenario C: Agreement sets principal, but the interest start date is disputed

This can happen when parties agree on an amount, but disagree on when it became legally enforceable or sufficiently certain to trigger interest.

How to use the calculator pragmatically:

• run multiple scenarios (e.g., “agreement date” vs. “effective date” vs. “judicial order date”)
• compare the outputs as an exposure range rather than a single definitive figure

Scenario D: You need to model multiple end dates

If you’re doing internal estimates for different milestones, you may hold the same start date and principal, and only change the end date.

Calculator inputs to model:

• keep principal and start date fixed
• change only the end date (e.g., filing date, judgment date, payment date, or reporting cutoff)

Result direction:

• later end date → more interest
• earlier end date → less interest

Quick reference: how inputs change outputs

Tips for accuracy

To keep outputs faithful to A.R.S. § 44-1201, focus on the inputs that drive both the legal condition and the math.

1) Choose the start date using the statute’s certainty condition

Because interest runs only when damages are made certain by agreement or by law, the most important accuracy step is selecting the correct start date.

Practical checklist:

• Does the agreement (settlement/contract/stipulation) specify a damages number or a formula that fixes the amount?
• Or does a legal ruling/judgment actually fix the damages number?
• Can you identify the record date that corresponds to “made certain”?

2) Ensure the principal matches the “certain” damages figure

Interest is calculated on damages. If your damages number includes amounts that you do not treat as part of the “certain” damages figure, your base may be wrong.

Checklist:

• Principal matches the damages amount you consider legally “certain”
• You avoid double-counting amounts you might handle separately (if applicable)

3) Be consistent with date handling and comparisons

Small date-handling choices can affect the day count used in the tool.

For consistent scenario comparisons:

• use the same day-count method across runs (if the tool allows it)
• keep date inputs in a consistent format (e.g., YYYY-MM-DD)
• rely on calendar dates (not timezone-shifted timestamps)

4) Model a range when the “made certain” date is contested

If you’re uncertain about the legally correct certainty date, don’t hide that uncertainty behind a single input.

Instead:

• run an “earliest plausible” start date scenario
• run a “likely” start date scenario
• run a “latest plausible” start date scenario
• compare the interest totals to understand exposure

5) Use the output as calculation support (not legal advice)

DocketMath’s calculator can quantify interest based on A.R.S. § 44-1201, but it cannot determine what qualifies as “made certain” for your specific facts. Use the results as support alongside your agreement/judgment record.

(General note: this content is informational and not legal advice.)

Sources and references

Start with the primary authority for Arizona 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
• Impact Calculator Guide for Colorado
• Impact Calculator Guide for Connecticut