Percentage discount calculation doesn't match my manual calculation

[johnTurne]

Discussion Type

Question

Discussion Content

Hi everyone,
I'm trying to calculate a percentage discount, but my manual calculation doesn't seem to match the result I'm getting.
For example:

• Original Price: $124.95
• Discount: 18%

I calculated the final price myself, then checked it using calculator.
The calculator gives a slightly different result than what I wrote down, so I'm wondering if I'm making a mistake with the formula or rounding.

Can someone explain the correct way to calculate a percentage discount step by step? Also, how should decimal values be rounded to get the correct final price?

Thanks in advance!

[bryansbtian]

Your formula is correct. Convert 18% to decimal form by dividing by 100:

18% = 0.18

Then calculate the discount:

$124.95 × 0.18 = $22.491

Subtract that from the original price:

$124.95 − $22.491 = $102.459

or another option you can do is just do (1 - discount) * original price to get the final price.

Since currency is normally displayed to two decimal places, round the final result to $102.46. The discount amount would display as $22.49.

It is best not to round intermediate values. Keep the full precision during the calculation, then round the final monetary result to two decimal places. A one-cent difference can happen when a calculator rounds the discount before subtracting it or uses a different rounding rule.