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How to Calculate an Additional Percentage

Adding on an extra percentage rather than a raw amount helps to measure the increase in relation to the original amount. For example, you might want to calculate the increase as a percentage of what you currently run or the increase in production costs as an added percentage of the original costs. Adding 5 miles a week would not be a huge increase for someone running 50 miles a week, but for someone only running 5 miles a week, that would double your mileage and your body may not be able to handle it. But adding the equivalent of 10 percent, or 1/2 mile, is more reasonable. Similarly, adding $5 to an item originally costing $10 adds 50 percent to the cost while adding $5 to an item originally costing $1,000 adds only 0.5 percent to the cost.

Calculator

Instructions

- 1
  Divide the extra percentage by 100 to find the number expressed as a decimal. For example, if you want to run 10 percent farther than you do currently, divide 10 by 100 to get 0.1. Alternatively, if you want to calculate an extra 20 percent added to a price because supply costs have increased, divide 20 by 100 to get 0.2.
- 2
  Multiply the decimal by your current amount to find the amount the extra percentage adds. In this example, if you currently run 30 miles a week, multiply 30 by 0.1 to get 3 miles. Alternatively, if the original cost equals $20, multiply $20 by 0.2 to get an increase of $4.
- 3
  Add the extra to the original amount to find the total after you add the extra percentage. In this example, add the extra 3 miles per week to the original 30 miles per week to get 33 miles per week. Alternatively, add the $4 extra to the original $20 cost to get a new cost of $24 per week.

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