Wales phases business rates rises from April 2026
If you run a shop, studio or small firm in Wales, your business rates may change after the 2026 revaluation. Welsh Ministers have signed off new rules that smooth any sharp increases. The Non-Domestic Rating (Chargeable Amounts) (Wales) Regulations 2025 take effect on 31 December 2025 and apply from 1 April 2026. In short: big rises are phased in over two years, with no phasing in the third year.
Let’s keep the promise simple before we get technical. If your bill goes up by more than £300 because of the new 2026 rating list, you won’t face the full jump straight away. In 2026–27 you pay 33% of the increase; in 2027–28 you pay 66%; by 2028–29 you’re on the full amount (unless other reliefs apply). The Welsh Government has set aside £116m to fund this support.
Who qualifies? You need to have been the ratepayer and in occupation on 31 March 2026 and still be the ratepayer on the day the bill applies. The property (called a “hereditament”) must also appear on the local list or the central list on 31 March 2026 and on each day up to the day in question. If part-occupation apportionment under section 44A applies, this phasing scheme does not.
Two terms you’ll see in official notes are BL and NCA. Base Liability (BL) is simply your bill for 31 March 2026, annualised. It uses the normal rules and includes any reliefs you already receive. Notional Chargeable Amount (NCA) is the bill that would apply from 1 April 2026 if there were no transitional phasing at all. If you were empty on 31 March 2026, there’s no BL for this scheme and you won’t qualify.
There’s a clear threshold test: your increase must be more than £300. In formula form used by Business Wales guidance, eligibility kicks in when NCA > (BL + £300). That keeps very small changes out of the scheme and focuses help where revaluation causes a meaningful jump.
How the phasing is worked out day by day matters for councils and utilities. In 2026–27, relief equals 67% of the increase between BL and NCA, calculated per day over 365 days. In 2027–28 the relief is 34% of that increase, calculated over 366 days because 2028 is a leap year. From 1 April 2028 to 31 March 2029 there’s no transitional deduction.
A quick example helps. Say your annualised BL is £12,000 and your NCA is £15,000. The increase is £3,000, which clears the £300 test. In 2026–27 you’d pay £12,000 + 33% of £3,000 = £12,990. In 2027–28 you’d pay £12,000 + 66% of £3,000 = £13,980. From 2028–29 the full bill of £15,000 applies, subject to any other reliefs you get. Councils may round to the nearest penny when doing the daily maths.
What if your valuation changes mid-way? If your chargeable amount goes down during the scheme-for example, after a successful appeal-the NCA is reset from the effective date and the relief is recalculated for the days affected. If the chargeable amount ever dipped below zero after applying the rules, it would be set to zero.
Administration is automatic. For properties on local lists, your council will recalculate bills without you applying. For central list properties (for example, some utilities), the Welsh Government will adjust bills directly. If you think your bill hasn’t been adjusted correctly, contact your local authority.
One more piece of context for 2026–27. Ministers have also signalled changes to the multipliers: a standard multiplier of 0.502, a lower retail multiplier of 0.350 for smaller shops, and a higher multiplier of 0.515 for the largest properties by value. These sit alongside the transitional phasing described above.
What this means for you: check your 31 March 2026 position, keep records of occupancy, and look at your draft 2026 valuation. If your increase is over £300 and you were in occupation on 31 March, expect the rise to be spread across two years. If you move out or change ratepayer, the phasing stops. The most up-to-date guidance and worked examples are on Business Wales.
Finally, a note on timing. The transitional rules apply to chargeable days from 1 April 2026 until 31 March 2029, even though there’s no deduction in the last year-this ensures a consistent way of calculating bills throughout the three-year period. The Regulations come into force on 31 December 2025, following Senedd approval.