MOT rules & problems
MOT Retest Rules Explained
Whether your retest is free, partially charged or a full new test depends almost entirely on where the car goes after the failure and how quickly it comes back.
Published by the Serviced247 editorial teamLast reviewed 29 August 2026Reviewed on rule change
Retest rules are the part of the MOT process that most directly affects what a failure costs you, and they are widely misunderstood. GOV.UK sets out the routes clearly; the practical trick is deciding which one you are on before you make a decision about where the repairs happen.
Key takeaways
- Leave the vehicle at the test station for repair and have it retested within 10 working days: the partial retest is free.
- Take the vehicle away and return within 10 working days: a partial retest may be carried out and a partial retest fee may apply.
- A defined list of items can be retested free if the vehicle is returned before the end of the next working day.
- Outside these routes you are looking at a full test at the station's usual price, capped at the statutory maximum.
- Always agree the retest arrangement before you drive away.
The free partial retest
If you leave the vehicle at the test station and it repairs the failed items, the partial retest is free provided the retest happens within 10 working days of the original test. This is the cleanest and cheapest route, and it is the reason garages that both test and repair are often the pragmatic choice after a failure.
The next-working-day route
For a specific list of items, you may take the vehicle away, have the repair done, and return it before the end of the next working day for a free retest of those items. This exists because some failures are simple, quick fixes that do not justify a charge.
Ask the station to confirm in writing which items your failure falls under before you leave, because the list is defined and not every defect qualifies.
When a partial retest fee applies
If you take the vehicle away for repair and return it within 10 working days, the station may carry out a partial retest and may charge a partial retest fee. What that fee is varies by station - it is not set by statute in the way the full test fee is.
When you need a full test again
Once you are outside the 10-working-day window, or the vehicle needs a complete re-inspection, you are booking a full MOT again. That is charged at the station's usual price, which may not exceed the statutory maximum of £54.85 for a Class 4 car.
Practical decisions this affects
- Whether to have the repair done at the test station or elsewhere
- Whether a cheaper repair quote elsewhere is still cheaper once a retest fee is added
- How quickly you need to get parts - the 10-working-day clock does not pause for backorders
- Whether to book the original test early in your renewal window so the clock is not also running on your certificate
What to ask before you leave the station
- Which retest route does my failure qualify for?
- What will the retest cost if I have the work done elsewhere?
- What is the last date I can return for a partial retest?
- Which failed items must be repaired, and which entries are advisories?