Accounting Share · Interest, loans & valuation

Loan Payment and Amortisation Calculator

Calculate a level monthly payment and an amortisation schedule showing interest, principal repayment and the remaining balance. A zero-rate loan is supported.

Free to useVisible formula & workingsNo account required

The interactive calculator requires JavaScript. The formula and worked example below remain available.

03 / Understand the method

Formula and method

Monthly payment = Principal × Monthly rate ÷ [1 − (1 + Monthly rate)^−Months]

Calculate a level monthly payment and an amortisation schedule showing interest, principal repayment and the remaining balance. A zero-rate loan is supported.

How to use this calculator

  1. Collect the figures for the same entity, currency and reporting period.
  2. Enter each input using its label and unit. For percentages, enter 15 to mean 15%.
  3. Choose Calculate, inspect the breakdown and compare the result with your assumptions.
  4. Change one input to explore a scenario. Recalculate after edits; display rounding does not round the underlying calculation.

Inputs at a glance

  • Loan principal: A nonnegative numeric input in the units specified by the label.
  • Nominal annual interest rate (%): A percentage number rather than a decimal fraction.
  • Term in months: A nonnegative numeric input in the units specified by the label.

Worked example

Follow one calculation.

Loan principal
12000
Nominal annual interest rate (%)
0
Term in months
12
Calculated result
1,000

Load this example in the interactive form to inspect the intermediate amounts and the full schedule.

Assumptions and interpretation

Assumes monthly payments in arrears, a fixed rate and no fees, extra payments or payment holidays. Rounding and lender-specific day counts may differ.

The output is a model based on the figures entered. Check source records and use the accounting or contractual definitions relevant to your task before relying on a result.

Questions about this tool

What does the loan payment and amortisation calculation measure?

Calculate a level monthly payment and an amortisation schedule showing interest, principal repayment and the remaining balance. A zero-rate loan is supported.

Which assumptions can change the result?

Assumes monthly payments in arrears, a fixed rate and no fees, extra payments or payment holidays. Rounding and lender-specific day counts may differ.

Why can displayed totals differ slightly from my spreadsheet?

Calculations use the unrounded input values. Only the display is rounded. Use four or six decimal places to inspect small differences, and check the timing, sign conventions and rounding policy in your spreadsheet.

Reference and further learning

Time value of money and loans. These original learning examples apply the displayed formula; the reference does not certify or endorse this calculator.

Look up an accounting term · Practise with accounting questions

Formula and worked example checked 4 November 2026. Calculations run in your browser without sending the entered figures to Accounting Share. Report a calculation issue with the tool name, example inputs and expected result; avoid sharing confidential records.

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