About
Built by someone who got sick of the price changing at the desk.
Car Rental Brain is a small, independent tool made by Jimi Walters in the UK. It started as a private script that watched rental prices for one airport, because the quoted price and the price at the counter were never the same number. It worked, so it became a website.
What it actually does
It asks every supplier on DiscoverCars for your dates, then re-prices the results the way you will really pay: the second-driver fee added when you say you need one, cross-border permission checked, deposit shown, fuel estimated if you tell us how far you are going. Then it sorts by that number instead of the sticker.
Three things it does that a plain search box does not:
- Beats a booking you have already made. Tell it your dates and what you paid; it checks every supplier for a cheaper like-for-like car. No confirmation number, nothing to cancel first.
- Splits long hires. Over about 40 days, two or three back-to-back rentals are often cheaper than one long booking. It prices every way of covering the period and tells you which wins.
- Keeps watching after you book. Most rentals cancel free, so a price drop is real money. Ask it to watch your dates and it emails you when rebooking is worth the bother.
How it makes money, plainly
Affiliate commission, and nothing else. If you book through a link here, DiscoverCars pays us a share; if you buy excess cover through a link here, that provider does. You pay the same price either way. There are no ads, no paid placements, and no fee to use the tool.
What that does not buy: position. Results are ordered by the real total, full stop. We earn the same whichever car you pick, we show suppliers that earn us nothing, and if commission ever moved a car up this page the whole thing would be pointless. The full version is on our affiliate disclosure page.
What we will not do
- No account, ever. No password to forget, nothing to delete.
- No tracking cookies, no analytics pixels, no ad networks. We do not store IP addresses.
- No selling your email. It is used for the alert you asked for, and that is the entire list of uses. See the privacy policy.
- No fake urgency. No "3 people are looking at this car." We do not know that, and neither do they.
Honest limits
Prices and availability come from DiscoverCars and the suppliers, and they are confirmed on the booking page before you pay — we can be out of date between your search and your click. Where a supplier does not publish its second-driver fee we estimate it from what comparable suppliers charge, and we label those cards as estimates rather than quietly hiding the car. Totals exclude insurance and extras so every option is compared like for like.
Get in touch
Questions, a bug, a rental that priced wrongly, or a partnership: hello@carrentalbrain.com. It is read by a person, usually the one who wrote the code.