Sumwise

Percentage Change from 30 to 20

From 30 to 20 is a 33.3333% decrease

Change
-33.3333%
Difference
-10
New ÷ old
0.666667
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: 20 − 30 = -10
  2. Divide by the starting value: -10 ÷ 30 = -0.333333
  3. Multiply by 100: -33.3333%
  4. Check: Work forwards from the start: 30 × (1 − 0.333333) = 30 × 0.666667 = 20.

In a spreadsheet: =(20-30)/30*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 66.6667% of the old one: for every 100 at the start there are now 66.6667, so 33.3333 out of every 100 have gone.

Sales: a price cut from $30 to $20 is a 33.3333% discount.

Why the change back is different

A 33.3333% fall followed by a 33.3333% rise does not bring you back to 30: it gives 26.6667. The second percentage is taken of 20, not of 30, so to undo this change you need 50% instead.

Related results

Results for nearby numbers
30 to 18

From 30 to 18 is a 40% decrease

30 to 19

From 30 to 19 is a 36.6667% decrease

30 to 21

From 30 to 21 is a 30% decrease

30 to 22

From 30 to 22 is a 26.6667% decrease

The other way round: Percentage change from 20 to 30. Percentage change is not symmetric: from 30 to 20 is -33.3333%, but from 20 back to 30 is 50%, because the starting value is the base. For a comparison that is the same both ways, use the percentage difference between 20 and 30: 40%. See Percentage difference between 20 and 30.

Practice

6 to 77
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From 6 to 77 is a 1,183.3333% increase

22 to 48
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From 22 to 48 is a 118.1818% increase

43 to 22
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From 43 to 22 is a 48.8372% decrease

12 to 99
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From 12 to 99 is a 725% increase

34 to 85
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From 34 to 85 is a 150% increase

2 to 59
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From 2 to 59 is a 2,850% increase

Calculate another

How answers are calculated and checked: methodology.

Questions

Percentage Change from 30 to 20

Going from 30 to 20 is a 33.3333% decrease. Formula and steps.

Is going from 30 to 20 an increase or a decrease?

A decrease: the value fell by 10, which is 33.3333% of the starting value.

What is the percentage change from 20 back to 30?

50%. It is a different number because the starting value is now 20, not 30.