The amount you pay in Business Rates is based on your property's rateable value. The rateable value is calculated by the Valuation Office Agency (external link).
Your Business Rates bill is calculated by multiplying the rateable value of the property by the "rate multiplier". There are two rate multipliers set annually by central Government.
The Small Business Multiplier - applies to business premises with a rateable value less than £51,000.
The Standard Multiplier - applies to all other businesses with a rateable value greater than £51,000.