We all know that there can be a pretty big disparity between the range numbers that car manufacturers give us and the reality of the situation — especially when it comes to WLTP, or the Worldwide Harmonized Light Vehicle Test Procedure numbers we get when it comes to electric vehicles.

The WLTP is an improvement over what European car makes were using to evaluate electric range, but it’s still not fully accurate when it comes to the real world. For the WLTP numbers, cars will undergo a dynamic test cycle that lasts 30 minutes and mimics urban and non-urban driving with different speeds, shift points, temperatures , and road conditions. But you’re still going to get figures that are about 10 percent higher than what you’d actually get when you hit the road.

For reference, American vehicles tend to use EPA regulations, and for EVs, the EPA test requires the EV be fully charged, left overnight, then but on a dynamometer that runs through city, highway, and steady-state drive cycles until the vehicle totally runs out of battery. It’s not an estimate like the WLTP; it’s an actual measurement of range.

So, to evaluate just how far off different WLTP range estimates are for popular electric cars, UK-based publication What Car? put 10 different EVs to the test on an old GM proving ground in Bedfordshire. Each car started out with a full charge and was repeatedly driven through the same 15-mile loop until it ran out of battery. That loop included 2.6 miles of simulated start-stop driving, four miles of 50 mph speeds, and eight miles of 70 mph speeds. A fairly reasonable comparison to a daily drive.

You can watch the full video below:

If you want to get straight to the point, that’s okay, too. The full results are below:

The numbers are honestly pretty fascinating. The Porsche Taycan may not have been the most efficient, but it was the car that most closely matched its WLTP rating in the real world. The electric Fiat 500 fell on the complete otherside of the spectrum. When it comes to the most miles achieved per kWh, the Tesla Model 3 was the clear winner — but if you're dealing with range anxiety, the Ford Mustang Mach-E's low efficiency but high range will probable be your best bet.