How much does an MOT retest cost?

Leave it to be fixed: You can ask the garage to fix the issues that caused the failure. If repairs are completed within 10 working days, they can do a partial retest where they will only test the issues listed on the VT30 certificate. If everything is in order, you’ll get a shiny new MOT certificate and there is no retest fee.
Bring it back within one working day: In some cases, you're entitled to take the car away for repairs and bring it back to the original testing centre for a free partial retest. You have just one day to do this. This option isn’t always available (particularly if the MOT test identifies faults that are dangerous). Your MOT tester will explain this, but you can find a full list of acceptable reasons why you can drive away and return for your retest on the DVSA website.
Bring it back within 10 working days: If you choose to have your car repaired elsewhere, you can take it back to the original testing centre for a partial retest within 10 working days of the initial test. If you return your vehicle within 10 days, the price for the retest will be up to half of the original MOT price you have paid.
Bring it back after 10 working days: If you bring your car back after 10 working days, you will be charged for a full MOT.