Lawn fertilizer calculator
Find the first number on the bag, the nitrogen percentage. The calculator works out how much product delivers the nitrogen your lawn needs.
Fertilizer to spread
20.8 pounds of product
- Bags
- 2 15 lb bags (1.39 exactly)
- Per 1,000 sq ft
- 4.17 lb of product
- Lawn area
- 5,000 sq ft
How it works
The three numbers on a fertilizer bag are the percentages of nitrogen, phosphorus and potassium by weight. To deliver 1 pound of nitrogen from a 24% product, you need 1 ÷ 0.24 = 4.17 pounds of fertilizer. The calculator does that for your target rate, then scales it to your lawn area.
Example
With lawn length 100 ft, lawn width 50 ft, nitrogen on the bag (first number) 24%, nitrogen per 1,000 sq ft 1 lb, bag weight 15 lb, the answer is 20.8 pounds of product.
Tips before you buy
- Many lawn care guides suggest no more than about 1 lb of nitrogen per 1,000 sq ft in a single application. Check the bag and any local rules.
- Don’t fertilize right before heavy rain. Sweep granules off driveways and sidewalks so they don’t wash into storm drains.
- Set your spreader using the bag’s chart, then compare how much product you actually used against this number.
Common questions
How much 24-0-6 fertilizer do I need per 1,000 sq ft?
About 4.2 pounds to apply 1 pound of nitrogen.
What do the three numbers on fertilizer mean?
The percentage of nitrogen (N), phosphate (P) and potash (K) by weight. A 50 lb bag of 10-10-10 holds 5 lb of each.
How much fertilizer for a 5,000 sq ft lawn?
With 24% nitrogen at 1 lb per 1,000 sq ft, about 21 pounds of product.