Using percentages in everyday business decisions
Percentage calculations are useful for price changes, discounts, growth, conversion rates and comparing one value with another. The important part is choosing the correct starting value.
Formula
Percentage change = (new value − old value) ÷ old value × 100.
Example
Raising a price from £80 to £100 is a 25% increase. Reducing £100 back to £80 is a 20% decrease because the starting values differ.
Common mistakes to avoid
- Assuming percentage increases and decreases reverse each other.
- Using percentage points and percentage changes as if they mean the same thing.
- Rounding too early when money calculations feed into later steps.
ProfitMaths provides general calculation tools and educational information. Results are estimates and are not accounting, tax, legal or financial advice.