ToolBirch

Loan Calculator

Monthly payment, total paid and interest for an amortising loan.Math & Statistics

Loan Calculator

Monthly payment, total paid and total interest for an amortising loan, using the standard annuity formula.

About this tool

The standard annuity formula gives the monthly payment; total paid and total interest follow. Zero-interest loans divide evenly instead of dividing by zero.

How to use the Loan Calculator tool

  1. Enter amount, rate and term. Annual rate as a percentage.
  2. Read the payment. Monthly amount, lifetime total, interest cost.
  3. Plan from there. The formula is stated so spreadsheets can match it.

Supported formats

Input

  • Plain text or file input

Output

  • Converted or analysed output

Inputs are validated before anything is processed. Invalid values and unsupported files are rejected with a clear error instead of failing silently.

Frequently asked questions

Which formula is used?

The fixed-rate amortisation formula M = P·r / (1 − (1+r)^−n).

What is excluded?

Taxes, insurance, fees and rate changes — this is the principal-and-interest payment only.

Does extra-principal show up?

No; this is the base schedule.

Privacy

Everything you enter stays in this browser tab. There is no upload endpoint for tool inputs, no account, and no server-side copy of your text or files. Results are produced locally and disappear when you close the page.

No account is required and no file is ever uploaded. See the privacy policy for details about analytics and the limited data this site stores.

Known limitations

  • No amortisation schedule table in this release.

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