Investing & Finance

Overdraft interest calculator

Even a few weeks in the red can cost you noticeable money. The calculator shows you the interest charge immediately.

Updated on Apr 21, 2026 Calculator, calculation path and examples on one page

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Related guide: Understanding ETFs, savings plans and compound interest

Examples

Typical calculations

1,800 euros for 30 days.

Short bottleneck

Interest costs: €17.61

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3,500 euros for 90 days.

Longer overdraft

Interest costs: €107.88

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FAQ

Frequently asked questions

How are overdraft interest calculated?

Banks charge interest on the amount used on a daily basis.

Why is the overdraft facility so expensive?

Because it is very flexible and can be used without a separate credit agreement.

When is an installment loan more worthwhile?

If you use the overdraft facility over several months or with larger amounts.

Are overdraft interest and overdraft interest the same thing?

Not quite. Overdraft interest often applies to amounts above the actual overdraft limit and is usually even higher.

Why does the calculator use 365 days?

This is a common basis for day-to-day interest calculations and is sufficiently precise for an approximate calculation.

How high are overdraft interest rates typically?

Many banks charge around 9 to 14 percent per year. You can find the exact rate in your bank's list of prices and services.

How can I avoid overdraft interest?

By balancing the account if possible, using a cheaper installment loan to refinance your debt or agreeing on an on-demand loan with a lower interest rate.

When are overdraft interest debited?

Quarterly billing is usual. The interest is calculated on the overdrawn amount on a daily basis and then debited to the account.

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Sources and notes

Rule status and context

Formula
Interest = amount × annual interest × days / 365
Note
Banks sometimes calculate 360 ​​or 365 days. Small deviations are therefore possible.