Percentage change
v1valor_inicialvalor_finalvariacionHow it is worked out
Work out the percentage a figure rose or fell between two points, such as a price or a salary.
Change is always measured against where you started: subtract the starting value from the final one, divide by the starting value and multiply by a hundred. From 120,000 to 150,000 there is a difference of 30,000 over 120,000, which is a rise of 25 %.
The expression that runs
(valor_final - valor_inicial) * 100 / valor_inicialThe fields arrive with an example filled in: put your own numbers in and run it again. You can also edit the formula to fit your case.
What if the formula were yours?
This calculator is not hand-written: it is an Axioma formula. Open it in the editor to see how it is built, adapt it to your case and create the ones you need.
Why it is divided by the starting value
A percentage needs a reference, and the reference is where you came from. The same 30,000 is 25 % if you started at 120,000 and 3 % if you started at a million: the difference on its own says nothing until it is compared with the starting point.
If the result comes out negative, the figure fell: from 150,000 back to 120,000 the change is minus 20 %, not minus 25, because the reference is now 150,000.
A 25 % rise and a 25 % fall do not cancel out
Going from 120,000 to 150,000 is a 25 % rise, but coming back from 150,000 to 120,000 is a 20 % fall. Each percentage is worked out on a different base, so they do not undo each other.
It is the same reason a share that drops 50 % needs a 100 % rise to get back to where it was, and it is worth remembering whenever a headline quotes a percentage.
What to watch when the starting point is awkward
If the starting value is zero there is no change to measure: there is nothing to compare against, and any figure would be an infinite rise. If the starting value is negative, the sign of the result stops meaning what you expect.
And when comparing periods, check they are comparable: a thirty day month against a thirty one day one, or a month with holidays against one without, produces changes that have nothing to do with what you are measuring.
Frequently asked questions
- How do I work out a percentage increase?
- Subtract the starting value from the final one, divide by the starting value and multiply by a hundred. From 120,000 to 150,000: 30,000 over 120,000, times a hundred, is 25 %.
- Why is my result negative?
- Because the final value is smaller than the starting one: the figure fell. The minus sign marks the fall and the number says how big it was.
- Does it work for several periods in a row?
- For each step on its own, yes. Chaining changes is not done by adding the percentages, because each one is worked out on the previous period value.