Your NCT falls due on the anniversary of the car's first registration. The regulations let you take the test up to 90 days before that date and still get a certificate dated from the old due date. Test any earlier and the rules change.
Inside 90 days: nothing lost
Say the test is due on 20 March and the car passes on 2 January, 77 days early. The new certificate runs to 20 March of the following year (or two years later for cars under ten years old). The weeks you gave up at the start are not deducted. This is why booking early is free in every sense, and why cancellation alerts are worth setting up as soon as your window opens.
Earlier than 90 days: voluntary early test
Pass the test more than 90 days before the due date and NCTS treats it as a voluntary early test. The car gets a full one or two year certificate counted from the day it passes, and the anniversary moves to that day for good. That can suit you: some people move a winter due date to summer this way, or line up the NCT with a sale. It costs you the unused months on the old certificate.
The rule was tightened for first tests: cars used to be allowed six months early for the four-year test; now the same 90 days apply.
Cars under four years old
- Under two years: can be tested, gets an inspection report but no certificate, and the due date stays at the fourth anniversary.
- Two to four years: a pass more than 90 days before the fourth anniversary gives a two-year certificate from the pass date, and the anniversary moves.
Work out your own window
The free due-date check on this site asks ncts.ie for your car's due date and shows the exact day the 90-day window opens. Inside the window, take any earlier date you can get. Outside it, decide whether you want the anniversary to move.
Where the fail case fits
If the car fails inside the window, the re-test deadlines (21 days to book, 30 to complete) run from the failed test, not from the due date. Passing the re-test before the due date still gives you a certificate from the old due date.
Frequently asked
Does the 90 days count calendar or working days?
Calendar days. Ninety days before the due date, counting every day.
I booked inside 90 days but the earliest date is after my due date. Am I penalised?
No penalty from NCTS, but between expiry and the test you have no valid certificate, which is a road traffic offence. Book anyway to hold a place, then watch for a cancellation to pull the date forward.
Can I choose voluntary early testing to move my due date?
Yes. Book and pass more than 90 days before the due date. The new anniversary is the pass date. Tell the agent or simply book; there is no separate form.
Does the 90-day rule apply to commercial vehicles?
No. Vans and trucks have the Commercial Vehicle Roadworthiness Test with its own rules. The NCT and this rule cover cars only.