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How do I calculate the interest and principal parts of a payment? Percentage split

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My statement says % of my monthly payment goes to interest. If the total payment is $ ...
How much goes to interest vs. principal?

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Answer: The interest is $ and the principal is $ .

Type of calculation: Calculating a percentage of a number (interest part), then subtracting (principal part).
How to use the calculator:
Step 1 (Interest part): Use the Basic Percentage Calculator (“What is A% of B?”). Enter 70 [A] and $1500 [B]. It will calculate 70% of $1500.
Step 2 (Principal part): Subtract the interest part (Step 1) from the total payment amount.
The formula:
We want to split the payment into interest (70% of $1500) and principal.
Interest part = (70 / 100) × $1500 = 0.7 × $1500 = $1050
Principal part = $1500 - $1050 = $450
For informational purposes only.

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App updated: August 2026