An overdraft fee is a flat charge, so what makes it expensive is not the size of the fee but how little you were short when it landed.
How it works
Most banks charge a flat fee for each transaction that overdraws the account. This calculator turns that into the figure that actually matters — the cost as a share of the amount the bank covered for you.
The smaller the overdraft, the worse the deal
A $35 fee on a $200 shortfall is 17.5% of the amount covered. The same $35 on a $10 coffee is 350%. The fee did not change; the thing it was charged against did. This is the opposite of how most costs behave, and it is why a run of small transactions after the balance hits zero is the expensive scenario — several are usually charged separately, so three $35 fees on one $200 shortfall is $105, or 52.5%.
What this does not include
Fee amounts are set by each bank rather than by regulation, so the fee is an input. This does not model daily sustained-overdraft charges that some banks add for every day the account stays negative, nor the separate, usually smaller, transfer fee charged by overdraft protection linked to a savings account.
How to use this calculator
- Enter how much you were short.
- Choose a flat fee or a percentage, and enter the amount from your disclosure.
- For a flat fee, enter how many separate overdraft charges were applied.
Frequently asked questions
Can I be charged several fees in one day?
Yes. Each transaction that overdraws the account is normally charged separately, so a few small purchases after the balance runs out can produce several fees on the same day. Some banks cap the number per day — the cap, if any, is in the disclosure.
Can I opt out of overdraft coverage?
For ATM and one-off debit card transactions, yes — and if you opt out those transactions are declined instead of being covered and charged. Declined is cheaper than a fee, though it means the payment does not go through. Checks and automatic payments are treated differently.
Is overdraft protection from a savings account cheaper?
Usually. Linking another account normally triggers a transfer fee of a few dollars rather than a full overdraft fee, and some banks charge nothing. It requires the money to be there, but where it is available it is almost always the cheaper route.
