Averaging nights let over 2 or 3 years
Since 1 April 2026, falling a few nights short of 182 in one year doesn't have to mean council tax. Here's how the averaging works in Wales.
Checked against legislation.gov.uk and GOV.WALES on 17 September 2026.
How it works
If your property was let for fewer than 182 nights in the 12 months before the day being checked, it's treated as passing if either of these is at least 182:
- the average of the last 2 years, or
- the average of the last 3 years.
They can give different answers, so both are worth checking. Each year is a full 12 months, back to back. For a check on 1 April 2026, the 3-year average looks at lettings from 1 April 2023 to 31 March 2026.
Years before April 2026 can go into the average. What changed is the date of the check, not which lettings count. You'll need booking records going back three years to use the 3-year average.
Worked examples
These follow the examples in the Welsh Government's guidance.
Passing on the 2-year average
| 12 months | Nights let |
|---|---|
| Latest | 170 |
| Year before | 200 |
| 2-year average | 185 |
170 on its own fails. The 2-year average of 185 passes.
Passing only on the 3-year average
| 12 months | Nights let |
|---|---|
| Latest | 170 |
| Year before | 190 |
| Two years before | 198 |
| 2-year average | 180 |
| 3-year average | 186 |
The 2-year average still falls short. The 3-year average passes.
Close isn't enough
170 then 193 averages 181.5. That's under 182, so it fails. The average isn't rounded up.
What averaging doesn't cover
- The 252 available nights. Averaging only applies to nights let. The property still has to have been available for 252 nights in the latest 12 months.
- Your plans for next year. You still need to intend to make it available for 252 nights over the next 12 months.
- What counts as a night let. The same rules apply in every year of the average: short stays only, cancellations don't count, and so on. What counts.
If you run several units on the same site as one business, averaging across years can be combined with averaging across the units. The calculator here doesn't do that yet, it checks one property at a time.
Check your own figures with the calculator. It works out the latest year, 2-year and 3-year results together.