## Percentage increase/decrease calculation

The percentage increase/decrease from old value (V_{old}) to new value (V_{new}) is equal to the old and new values difference divided by the old value times 100%:

percentage increase/decrease = (*V*_{new} - *V*_{old}) / *V*_{old} × 100%

#### Example #1

Price percentage increase from old value of $1000 to new value of $1200 is caluclated by:

percentage increase = ($1200 - $1000) / $1000 × 100%

= 0.2 × 100% = 20%

#### Example #2

Price percentage decrease from old value of $1000 to new value of $800 is caluclated by:

percentage decrease = ($800 - $1000) / $1000 × 100%

= -0.2 × 100% = -20%

## Difference and final value calculation

The difference d is equal to the initial value *V*_{0} times the percentage increase/decrease p divided by 100:

*d* = *V*_{0} × *p* / 100

The final value *V*_{1} is equal to the initial value *V*_{0} plus the difference d:

*V*_{1} = *V*_{0} + *d*