Fertilizer Calculators
Fertilizer advice is written in pounds of nutrient, but you buy pounds of product. Convert any N-P-K grade and target rate into exact amounts, for granular, liquid and water-soluble fertilizers.
The one formula to remember
To apply 1 lb of nitrogen with a 20-5-10 fertilizer you need 1 ÷ 0.20 = 5 lb of product. The Fertilizer Calculator does this for any area and grade; the Liquid Fertilizer Dilution Calculator scales label rates to any watering can or mixes to a target ppm.
Always follow product labels and local regulations, and base phosphorus and potassium on a soil test where possible.
FAQ
Common questions
What do the numbers on fertilizer mean?
The percentage by weight of nitrogen (N), phosphate (P₂O₅) and potash (K₂O).
Can I use less fertilizer than recommended?
Yes, feeding less, more often is gentler on plants and reduces the risk of runoff.
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