Max Bid Calculator

The mistake every new flipper makes is bidding from the gut. They see a car they like, the price is climbing, and they convince themselves an extra £200 won't matter. It does. £200 is your entire MOT and advisory budget, gone before you've even collected the car.

Set your max bid before the auction starts. Work backwards from a realistic sale price — what AutoTrader comps actually sell for, not what they're listed at. Subtract every cost: buyer's premium, transport from the auction yard, prep, the listing fee. Subtract the profit you need to make this worth doing. What's left is your absolute ceiling.

Then bid 10–15% below that. The buffer is your insurance against surprises — a tyre you didn't spot, a warning light the engine bay didn't show, a stubborn buyer who takes an extra two weeks.

BCA, Manheim and Copart all use tiered buyer's premiums. Bid £1,499 and your BCA fee is £150 + VAT. Bid £1,501 and it's 10% of hammer + VAT — about £180 on that bid. Two pounds higher, thirty pounds more out of pocket.

Motorway and CarWow are simpler — flat fees regardless of hammer price. That makes them easier to plan for but slightly more expensive at the low end.

This calculator handles the maths properly. It iterates: starts with a guess for your max bid, looks up the fee at that bid level, recalculates the max, and repeats until it stabilises. So you get the right answer for sliding-scale platforms, not an approximation. Read more about UK auction platforms.

The single most profitable habit at any car auction is walking away. When the bidding pushes you past your max, you stop. Even if you love the car. Even if you've already mentally bought it.

Cars come up every day. There are thousands of auction cars listed across Motorway, CarWow, BCA and Manheim in any given week. If you miss one, the next one will be cheaper or better. See the full guide to UK car flipping.