The most expensive 100 you can borrow.

Bank overdrafts are among the most expensive borrowing products. Overdraft EARs (equivalent annual rates) run 35-50% for most major banks - higher than most credit cards. This calculator shows the real annual cost of regular overdraft usage.

A 500 overdraft used 15 days a month at 1 daily fee costs 15 monthly or 180 annually. Against a 500 average balance, that's a 36% effective annual rate. If the monthly cap is 5 daily × 22 days = 110 - the cost still tops 100/month despite the cap.

The tool shows monthly cost, annual cost, and effective annual rate. Anyone seeing 35%+ effective rate should consider alternatives: overdraft replaced by a low-rate credit card, a personal loan, or simply timing the overdraft to fewer days. The fee structure punishes long usage, so reducing days often beats reducing amount.

Run it with sensible defaults

Using typical overdraft balance of 500, days per month overdrawn of 15, daily fee of 1, monthly cap of 80, the calculation works out to 180.00. Nudge the inputs toward your own situation and the output recalculates instantly. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Typical Overdraft Balance, Days Per Month Overdrawn, Daily Fee, and Monthly Cap (0 for None) — do not pull with equal force. Frequency and unit price pull the total in different directions. The biggest surprise for most people is how small recurring amounts compound into large annual figures — that's where this calculation earns its keep.

How the math works

Raw monthly cost = days × daily fee. Capped monthly = min(raw, cap) or raw if cap is 0. Annual = capped × 12. Effective rate = annual / overdraft amount. The working is transparent — you can verify every step yourself in the formula section below. No black box, no opaque "proprietary model".

Using this to stay on track

The most common failure mode isn't the plan itself — it's letting the balance creep back up while you're paying it down. Set a rule: no new debt added to the same account until the balance is zero. The calculator is only useful if the number it shows doesn't keep resetting.

What this doesn't capture

Real payoff journeys include missed payments, fee changes, balance transfers, and promotional rates that reset. The calculation assumes a steady plan; reality is rarely that clean. Use the figure as the best-case plan against which actual progress gets measured.