If you want to calculate the percentage change between value old_value and new_value, this is done using the formula:

percentage change = ( new_value – old_value ) / old_value

For example if your sales figures are $12,500 in January and $17,500 in February, the percentage change in February, compared to January, is given by:

percentage change = ( $17,500 – $12,500 ) / $12,500

This gives the result 0.4, or +40%

This percentage calculation is shown in the spreadsheet below.

  A B C D
1 Data Description    
2 $12,500. January sales    
3 $17,500. February sales    
4 $16,000 March sales     
5        
6 Formula Result Notes
7 =(A3-A2)/A2 40% In order to get the result displayed as a percentage, formatting for cell C6 was set to percentage
8 =(A4-A3)/A3 -8.6% A negative percentage results from a decline in sales from February to March