Sumwise

Percentage Change from 20 to 10

From 20 to 10 is a 50% decrease

Change
-50%
Difference
-10
New ÷ old
0.5
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: 10 − 20 = -10
  2. Divide by the starting value: -10 ÷ 20 = -0.5
  3. Multiply by 100: -50%
  4. Check: Work forwards from the start: 20 × (1 − 0.5) = 20 × 0.5 = 10.

In a spreadsheet: =(10-20)/20*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 50% of the old one: for every 100 at the start there are now 50, so 50 out of every 100 have gone.

Sales: a price cut from $20 to $10 is a 50% discount.

Why the change back is different

A 50% fall followed by a 50% rise does not bring you back to 20: it gives 15. The second percentage is taken of 10, not of 20, so to undo this change you need 100% instead.

Related results

Results for nearby numbers
20 to 8

From 20 to 8 is a 60% decrease

20 to 9

From 20 to 9 is a 55% decrease

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From 20 to 11 is a 45% decrease

20 to 12

From 20 to 12 is a 40% decrease

The other way round: Percentage change from 10 to 20. Percentage change is not symmetric: from 20 to 10 is -50%, but from 10 back to 20 is 100%, because the starting value is the base. For a comparison that is the same both ways, use the percentage difference between 10 and 20: 66.6667%. See Percentage difference between 10 and 20.

Practice

4 to 79
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From 4 to 79 is a 1,875% increase

74 to 32
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From 74 to 32 is a 56.7568% decrease

23 to 30
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From 23 to 30 is a 30.4348% increase

53 to 57
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From 53 to 57 is a 7.5472% increase

75 to 96
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From 75 to 96 is a 28% increase

51 to 55
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From 51 to 55 is a 7.8431% increase

Calculate another

How answers are calculated and checked: methodology.

Questions

Percentage Change from 20 to 10

Going from 20 to 10 is a 50% decrease. Formula and steps.

Is going from 20 to 10 an increase or a decrease?

A decrease: the value fell by 10, which is 50% of the starting value.

What is the percentage change from 10 back to 20?

100%. It is a different number because the starting value is now 10, not 20.