How do you calculate the NPK ratio for fertilizers?

To calculate the NPK ratio for fertilizers, you need to look at the numbers on the fertilizer packaging. The NPK ratio represents the percentage of nitrogen (N), phosphorus (P), and potassium (K) in the fertilizer. Simply divide the percentage of each nutrient by the total percentage of all three nutrients and multiply by 100 to get the ratio. For example, if a fertilizer has 10 nitrogen, 5 phosphorus, and 5 potassium, the NPK ratio would be 10-5-5.