National non-domestic rating multiplier
The local authority works out the business rates bill for a property by multiplying the rateable value of the property by the appropriate non-domestic multiplier. There are two multipliers: the standard non-domestic rating multiplier and the small business non-domestic rating multiplier. The government sets the multipliers for each financial year, except in the City of London where special arrangements apply.
Ratepayers who occupy a property with a rateable value which does not exceed £50,999 (and who are neither entitled to certain other mandatory relief[s] nor liable for unoccupied property rates) will have their bills calculated using the lower small business non-domestic rating multiplier, rather than the standard non-domestic rating multiplier.
Both multipliers for a financial year are based on the previous year's multiplier adjusted to reflect the Consumer Price Index (CPI) inflation figure for the September prior to the billing year, unless a lower multiplier is set by the government. The current multipliers are shown on the front of your bill.