If you enter a ULEZ area without the correct emission output, you'll be charged £12.50 a day. If you enter the zone more than once a day, you will still only get charged the £12.50, as it's a fee for the entire 24 hours and not for each journey.  This means that if you're entering the ULEZ area for work five days a week with a car that's not compliant, you could be changed up to £250 a month on top of the unavoidable congestion charge if you enter central London. That can increase your bills by more than £3,000, which can seriously affect your finances. Because the fees can get so expensive, it's best to know where the ULEZ cameras are so that you can avoid them and ensure you're not entering the area accidentally.