I have two numbers (1530 and 1315). How do I calculate the percentage difference.

For example: I have one loader that lifts 1530 lbs. and another loader that lifts 1315 lbs. I know the difference is 215 lbs. How much greater lift capacity does the loader that lifts 1530 lbs. have than the loader that lifts 1315 lbs.?

The formula that I used was:

1530 - 1315 = 215
215/1315 = .163498 or 16.3%

Is this correct?

People often get confused with the percentage differences between things because it depends on perspective. If you have 3 apples and I have 1 apple, you have 200% more than me, but I have 67% less than you (equivalently, you have 300% of my lunch and I have 33% of yours).

The key word in these sentences, which lets you understand what is going on, is "than". The placement of the word indicates which direction you are viewing things from. The percentage is calculated as the difference divided by the quantity after the "than":

"16.3% more lift capacity than the 1315 lb unit" means 1315(1.163) = 1530 lbs.

If you said (incorrectly) "16.3% less lift capacity than the 1530 lb unit", that would mathematically mean 1530(0.837) = 1281 lbs (not right at all!)

However, if the question was worded instead "how much less does the small lifter have than the large lifter", that would mean (1530-1315)/1530 = 14.1%

It's a matter of knowing which perspective you need to use. This subtlety is used to significant effect in consumer mathematics. For example, if I have a mop at regular price and I take 25% off for a sale, what percentage do I add to the sale price to return it to the original price later? Answer: 33%. There's nothing devious here, but it matters which of the two prices you use as your reference.

Stephen La Rocque.>