Revaluation in Practice: Modelling Business Rates as an Occupancy Cost

Most professional firms budget for business rates the way they budget for postage: a small, dull line item, indexed roughly and forgotten. The 2026 revaluation, effective in England from 1 April 2026, has made that habit expensive. Firms that modelled the new liability by inflating their 2023 bill by a headline percentage are now discovering that rateable value is a rental judgement, not an inflation index — and that the judgement was made about a property market two years old before it reached a bill.

What the revaluation did, and did not, change

Rateable value is a hypothetical annual rent, assessed at the antecedent valuation date of 1 April 2024. Because that date now sits behind us, the 2026 list already carries a lag: occupiers whose leases were renewed in a soft 2025 market may hold a rateable value that reflects a firmer 2024 reading, and vice versa. The list runs to 31 March 2029, when the next revaluation takes effect. That three-year rhythm matters for two reasons: challenges have a deadline, and lease events falling in 2027 and 2028 will be negotiated against a valuation that is quietly ageing.

Rateable value is only half the calculation. The multiplier does the rest, and England now operates several: a standard multiplier, a small business multiplier for properties below the £51,000 rateable value threshold, and a permanently lower multiplier for retail, hospitality and leisure premises. Offices, laboratories and studio space sit outside that final category almost without exception, so the relief widely reported in the trade press does little for most professional occupiers.

For illustration only — the applicable multiplier depends on the individual assessment — a 4,000 sq ft office at a rateable value of £180,000 produces an annual charge of roughly £90,000 at a multiplier in the region of 50p, or about £22.50 per sq ft. A comparable floor plate in a regional centre at a rateable value of £110,000 produces about £55,000, or £13.75 per sq ft. That gap, multiplied across a decade of lease term, is a strategic number rather than an admin one.

Transitional relief is not a subsidy

Transitional relief caps increases in bills following a revaluation, and it is habitually described in board papers as protection. It is better understood as a smoothing mechanism that is self-financing: reductions in bills are phased in as well as increases, and the caps tighten according to rateable value band, with the largest properties receiving the least comfort. Two practical consequences follow. First, a firm enjoying a cap should model the step-up at the end of the scheme, not merely the capped figure for 2026/27. Second, a firm whose bill has fallen may find the benefit arriving more slowly than the valuation suggests — which is a cash-flow issue in the year of a relocation, not a rounding error.

The void period is where budgets break

Empty property relief is a blunt instrument. For offices and most studio space, relief runs for three months; for industrial and warehouse premises, six months. After that, the full charge applies on an unoccupied building, without the small business multiplier and without occupation. Firms holding surplus floor plates while a sublease is negotiated routinely underestimate this, and the arithmetic is unforgiving: three empty months on a £90,000 annual liability is a £22,500 surprise in a year that also carries dilapidations, service charge and rates on the new premises.

Deliberate short-term occupation designed to reset the void period is a known practice and a known risk. Billing authorities increasingly test whether occupation is genuine and substantial, and a contested rates avoidance case is a poor use of a managing partner's attention.

Check, Challenge, Appeal — in that sequence

The statutory route in England has three stages, and they cannot be reordered.

• Check. A factual enquiry of the Valuation Office Agency: floor areas, use, car parking, plant, whether a mezzanine was ever completed. This is where most errors are found, and it is cheap to do.
• Challenge. A professional opinion that the valuation is wrong, supported by comparable evidence, quantum arguments or scheme analysis. This is where surveyors earn their fee.
• Appeal. A reference to the Valuation Tribunal if the challenge is not resolved.

For the 2026 list, the long-stop deadline for a challenge is 31 March 2029, but early action is worth more than the deadline implies. Alterations arising from a challenge can generate a credit, and the timing of that credit depends on when the process started. A firm that files in 2028 has financed the authority for two years at its own expense.

The relocation arithmetic worth running now

Before a 2027 budget is locked, four calculations should be on the page rather than in an adviser's inbox:

1. Rates per square foot, current premises against each shortlisted option, using each property's own rateable value rather than an average.
2. Rates per desk, which corrects for density. A building with a higher rateable value but better desk efficiency can be cheaper per head than a cheaper building with poor floor-plate geometry.
3. Rates as a share of total occupancy cost — rent, service charge, insurance, utilities and rates combined. Firms frequently discover that rates are 18 to 25 per cent of the total, a proportion that changes the negotiating posture on rent-free periods.
4. The step-up profile for the first three years, incorporating any transitional cap and its expiry.

Two further points deserve attention. Improvement relief can exclude qualifying works from the assessment for a period, which changes the arithmetic on laboratory fit-out and heavy studio installations. And where a firm takes a newly fitted space, the rating assessment may not yet reflect the works — a future liability to model rather than a current saving to bank.

Five actions before the budget is signed off

Read the 2026/27 bill against the assessment, not against last year's payment. Verify the floor area on the VOA record. Confirm which multiplier applies and whether any relief is being applied correctly. Diarise the transitional cap expiry. And put a rates line in the relocation model at property level, per desk, with the void period priced in.

None of this is glamorous. All of it is cheaper than discovering, eighteen months into a ten-year lease, that the rates line was the one figure nobody tested.