Skip to content
ENExplore Calculators

Overdraft Interest Calculator

Work out overdraft interest instantly with clear inputs, formula shown and shareable results.

About Overdraft Interest Calculator

An overdraft charges interest only on the amount actually drawn and only for the days it is outstanding, computed on a daily basis. That makes it cheap for short, uneven needs and expensive if a balance is left standing.

Formula

Overdraft interest

Interest = drawn × annual rate × days / 365

Worked example

With the default values below, Overdraft Interest Calculator returns Interest Charged of $8,013.70. Change any input above and every figure here is recalculated in your browser.

Inputs used

Amount Drawnminimum 0
500,000
Annual Interest Rateaccepts 0–100 %
13 %
Days Outstandingaccepts 1–366
45

Results

Interest Charged
$8,013.70
Interest Per Day
$178.08
Cost For A 30-Day Month
$5,342.47
Total To Repay
$508,013.70

Step by step

  1. 1Values used
  2. 2Overdraft interest
  3. 3Interest Charged= 8,013.70
  4. 4Interest Per Day= 178.08
  5. 5Cost For A 30-Day Month= 5,342.47
  6. 6Total To Repay= 508,013.70

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax or fees or charges into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Figures are estimates. Lenders apply their own rounding, fees and eligibility rules, and rates change. This is not financial advice — confirm the numbers with your lender.
  • This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Figures are estimates. Lenders apply their own rounding, fees and eligibility rules, and rates change. This is not financial advice — confirm the numbers with your lender.

Frequently Asked Questions

Why is an overdraft cheaper than a term loan for short needs?

Because interest stops the day you repay, so there is no cost for months you do not use the money.

What other charges apply?

Renewal and processing fees, and sometimes a commitment fee on the unused portion of the limit.

Related Calculators

Overdraft Interest Calculator – Calculate Interest Charged