---
title: How we rank UK overdrafts | overdrafts.com
description: "The formula behind the leaderboard: each bank’s advertised EAR compounded daily over 30 days on £250, minus any interest-free buffer. Sources, cadence and corrections policy."
image: https://overdrafts.com/brand/og-default.png
canonical: https://overdrafts.com/methodology/
updated: 2026-08-29
---

# How we rank

## The formula

Every figure on the leaderboard is the same calculation, run on every bank with no adjustments:

charged = max(amount − buffer, 0)

daily = (1 + EAR)^(1/365) − 1

cost = charged × ((1 + daily)^30 − 1)

We take the bank’s advertised EAR, convert it to a daily rate, and compound it over 30 days on the amount overdrawn, minus any interest-free buffer. It’s the same method banks use to charge you, and the results match the banks’ own published examples.

## A worked example

£250 overdrawn for 30 days at 39.9% EAR, no buffer:

Amount charged interest

£250

Daily rate from 39.9% EAR

0.0920%

Cost over 30 days

−£7.00

## What we assume

-   30 days continuously overdrawn, in an arranged overdraft.
-   Each bank’s interest-free buffer is applied before interest.
-   Where a bank prices by tier, the board shows its best advertised tier and says so on the row.

## Sources

Every rate comes from the bank’s own published rate pages, never from a comparison feed. Each bank’s page links its source with the date we last checked it. No bank pays to appear, rank, or be excluded.

## The business board

[The business leaderboard](https://overdrafts.com/business/) uses the same formula at £25,000, the amount the banks’ own representative examples assume. Business rates are representative: the rate the bank expects at least 51% of accepted customers to get, taken from the bank’s public product feed or its published rates page. Your offer can differ.

Business overdrafts often carry arrangement fees. We show every published fee beside the rate, and we never fold fees into the ranked interest figure, because doing so would need an assumption about how long you keep the facility, and the banks don’t publish one. Ranked by interest, fees in plain sight.

## Cadence

We re-check every bank every day. Changes are logged permanently on [the changes page](https://overdrafts.com/changes/), including the ones banks make quietly.

## Corrections

If a published figure is wrong, we correct it as soon as we know and log the correction on [the changes page](https://overdrafts.com/changes/), which is never edited after the fact.

[← Back to the leaderboard](https://overdrafts.com/#board)

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