Sumwise

Percentage Change from 100 to 90

From 100 to 90 is a 10% decrease

Change
-10%
Difference
-10
New ÷ old
0.9
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: 90 − 100 = -10
  2. Divide by the starting value: -10 ÷ 100 = -0.1
  3. Multiply by 100: -10%
  4. Check: Work forwards from the start: 100 × (1 − 0.1) = 100 × 0.9 = 90.

In a spreadsheet: =(90-100)/100*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 90% of the old one: for every 100 at the start there are now 90, so 10 out of every 100 have gone.

Sales: a price cut from $100 to $90 is a 10% discount.

Why the change back is different

A 10% fall followed by a 10% rise does not bring you back to 100: it gives 99. The second percentage is taken of 90, not of 100, so to undo this change you need 11.1111% instead.

Related results

Results for nearby numbers
100 to 88

From 100 to 88 is a 12% decrease

100 to 89

From 100 to 89 is a 11% decrease

100 to 91

From 100 to 91 is a 9% decrease

100 to 92

From 100 to 92 is a 8% decrease

The other way round: Percentage change from 90 to 100. Percentage change is not symmetric: from 100 to 90 is -10%, but from 90 back to 100 is 11.1111%, because the starting value is the base. For a comparison that is the same both ways, use the percentage difference between 90 and 100: 10.5263%. See Percentage difference between 90 and 100.

Practice

19 to 73
Show answer

From 19 to 73 is a 284.2105% increase

89 to 68
Show answer

From 89 to 68 is a 23.5955% decrease

2 to 69
Show answer

From 2 to 69 is a 3,350% increase

9 to 49
Show answer

From 9 to 49 is a 444.4444% increase

60 to 62
Show answer

From 60 to 62 is a 3.3333% increase

97 to 7
Show answer

From 97 to 7 is a 92.7835% decrease

Calculate another

How answers are calculated and checked: methodology.

Questions

Percentage Change from 100 to 90

Going from 100 to 90 is a 10% decrease. Formula and steps.

Is going from 100 to 90 an increase or a decrease?

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

What is the percentage change from 90 back to 100?

11.1111%. It is a different number because the starting value is now 90, not 100.