Sumwise

Percentage Change from 90 to 80

From 90 to 80 is a 11.1111% decrease

Change
-11.1111%
Difference
-10
New ÷ old
0.888889
Direction
decrease

Sumwise · Maintained by Theo Abbott (pen name) · automated checks · Data: exact arithmetic; unit definitions from NIST SP 811 · Updated · How the checks work

How to work it out

  1. Difference: 80 − 90 = -10
  2. Divide by the starting value: -10 ÷ 90 = -0.111111
  3. Multiply by 100: -11.1111%
  4. Check: Work forwards from the start: 90 × (1 − 0.111111) = 90 × 0.888889 = 80.

In a spreadsheet: =(80-90)/90*100. Always divide by the starting value, not the new one. A rise from 40 to 50 is +25%, but the fall from 50 back to 40 is −20%.

What the result means

The new value is 88.8889% of the old one: for every 100 at the start there are now 88.8889, so 11.1111 out of every 100 have gone.

Sales: a price cut from $90 to $80 is a 11.1111% discount.

Why the change back is different

A 11.1111% fall followed by a 11.1111% rise does not bring you back to 90: it gives 88.8889. The second percentage is taken of 80, not of 90, so to undo this change you need 12.5% instead.

Related results

Results for nearby numbers
90 to 78

From 90 to 78 is a 13.3333% decrease

90 to 79

From 90 to 79 is a 12.2222% decrease

90 to 81

From 90 to 81 is a 10% decrease

90 to 82

From 90 to 82 is a 8.8889% decrease

The other way round: Percentage change from 80 to 90. Percentage change is not symmetric: from 90 to 80 is -11.1111%, but from 80 back to 90 is 12.5%, because the starting value is the base. For a comparison that is the same both ways, use the percentage difference between 80 and 90: 11.7647%. See Percentage difference between 80 and 90.

Practice

18 to 51
Show answer

From 18 to 51 is a 183.3333% increase

99 to 89
Show answer

From 99 to 89 is a 10.101% decrease

48 to 28
Show answer

From 48 to 28 is a 41.6667% decrease

25 to 38
Show answer

From 25 to 38 is a 52% increase

18 to 48
Show answer

From 18 to 48 is a 166.6667% increase

39 to 31
Show answer

From 39 to 31 is a 20.5128% decrease

Calculate another

How answers are calculated and checked: methodology.

Questions

Percentage Change from 90 to 80

Going from 90 to 80 is a 11.1111% decrease. Formula and steps.

Is going from 90 to 80 an increase or a decrease?

A decrease: the value fell by 10, which is 11.1111% of the starting value.

What is the percentage change from 80 back to 90?

12.5%. It is a different number because the starting value is now 80, not 90.