Worked example: Interest in Philippines

Example inputs

Run this scenario in DocketMath using the Interest calculator.

Below is a worked example of calculating interest (PH) for a Philippines scenario using DocketMath. This walkthrough is designed to show how to set inputs and how the result changes when you tweak assumptions—not to provide legal advice.

Scenario (illustrative)

You’re calculating interest for a sum of money in the Philippines where interest is expected to accrue across a period.

Assume:

• Principal: PHP 100,000
• Start date (interest accrues from): 2024-01-15
• End date (interest stops on): 2024-06-20
• Compounding: None (simple interest style for this example)
• Interest rule selection: DocketMath applies jurisdiction-aware rules for PH based on the date range and your chosen rule inputs.

What to enter in DocketMath (PH / interest tool)

Start at the interest calculator:

• Primary CTA: /tools/interest

If your DocketMath UI asks for rule-related fields, map them like this:

• Jurisdiction: PH
• Principal amount: 100000
• From date: 2024-01-15
• To date: 2024-06-20
• Interest rate: Choose the applicable rate input you want to test in your model (see Sensitivity check below).

Because interest rules can depend on the legal basis (e.g., contract vs. forbearance vs. judgment), this example shows how to run the calculator with explicit rates so you can compare outputs. If you have a specific governing rate, you should use that rate in the calculator rather than a placeholder.

Rate assumptions for the example runs

To keep the example transparent, we’ll run three interest-rate variants:

Example run

To run the example in DocketMath:

1. Open /tools/interest
2. Set Jurisdiction to PH
3. Enter the principal, from date, and to date:

   • Principal: PHP 100,000
   • From: 2024-01-15
   • To: 2024-06-20
4. Select/enter the annual rate for the run (A, B, or C).
5. Choose simple (no compounding) for this example.

Date duration used

DocketMath will compute the number of days between:

• 2024-01-15 → 2024-06-20

For this example, that interval is 157 days.

Simple interest formula (as reflected in the calculator)

When using simple interest (no compounding), the interest typically follows:

• **Interest = Principal × Rate × (Days / 365)

Run A: 6.0% annual rate

Inputs:

• Principal = 100,000
• Rate = 6.0% = 0.06
• Days = 157
• Year basis = 365

Computation:

• Interest = 100,000 × 0.06 × (157 / 365)
• Interest ≈ 100,000 × 0.06 × 0.4301
• Interest ≈ PHP 2,580.82

Total amount (Principal + Interest):

• ≈ PHP 102,580.82

Run B: 9.0% annual rate

Inputs:

• Rate = 0.09

Computation:

• Interest = 100,000 × 0.09 × (157 / 365)
• Interest ≈ 100,000 × 0.09 × 0.4301
• Interest ≈ PHP 3,871.22

Total amount:

• ≈ PHP 103,871.22

Run C: 12.0% annual rate

Inputs:

• Rate = 0.12

Computation:

• Interest = 100,000 × 0.12 × (157 / 365)
• Interest ≈ 100,000 × 0.12 × 0.4301
• Interest ≈ PHP 5,161.64

Total amount:

• ≈ PHP 105,161.64

Sensitivity check

Now we stress-test the result to show exactly what moves the number the most. In interest calculations, three levers usually dominate:

• Annual rate
• **Time window (days)
• Compounding vs. simple interest

This section compares outputs as you change one lever at a time.

1) Rate sensitivity (holds dates constant)

Keep the same principal (PHP 100,000) and the same dates (157 days). Only change the annual rate.

Observation:
Each 3% increase produces roughly PHP 1,290.41 more interest over this 157-day period (because the calculation is linear under simple interest).

2) Timing sensitivity (holds rate constant at 9.0%)

Now keep the annual rate at 9.0% and vary the end date.

Example alternative end dates:

• Earlier end: 2024-05-20
• Baseline end: 2024-06-20
• Later end: 2024-07-20

Conceptually, DocketMath counts exact calendar days between the two dates. Using the example-day counts:

• From 2024-01-15 to 2024-05-20 = 126 days
• From 2024-01-15 to 2024-06-20 = 157 days
• From 2024-01-15 to 2024-07-20 = 187 days

Interest at 9.0%:

• Earlier end (126 days):
  Interest = 100,000 × 0.09 × (126/365) ≈ PHP 3,105.48
• Baseline end (157 days):
  Interest ≈ PHP 3,871.22
• Later end (187 days):
  Interest = 100,000 × 0.09 × (187/365) ≈ PHP 4,610.96

Observation:
Shifting the end date by ~30 days can change interest by about PHP 765–740 for a PHP 100,000 principal at 9% simple interest.

3) Compounding toggle (if available in your tool)

Some calculators let you choose compounding. If you enable compounding, the interest will no longer be strictly linear with time, especially for longer periods.

Checklist when you toggle compounding:

• Confirm the compounding frequency (monthly, quarterly, etc.) if DocketMath asks.
• Re-run the same principal/date/rate inputs.
• Compare:

  • Simple interest output (baseline)
  • Compounded interest output (scenario)

For short windows like 157 days, differences are often smaller than for multi-year periods, but compounding can still increase totals.

Related reading

• Interest rule lens: Maine — The rule in plain language and why it matters
• Common interest mistakes in Rhode Island — Common errors and how to avoid them
• Worked example: interest in Maine — Worked example with real statute citations