Fertilizer Nutrient Units Calculator

Product rate times guaranteed analysis. Converts 10-20-10 into pounds of N, P2O5, and K2O. Not a GDD clone.

Formula

lb nutrient / acre = product lb/acre × (analysis % / 100)

A 10-20-10 grade is 10% N, 20% P2O5, 10% K2O by weight.
To hit a nitrogen target: product = target N / (N% / 100).

P2O5 × 0.436 = elemental P. K2O × 0.830 = elemental K.
This page reports oxide units as on the bag.

References

1. IPNI / AAPFCO guaranteed-analysis convention. Fertilizer grade is percent N, available phosphate as P2O5, soluble potash as K2O.
2. Land-grant extension nutrient-management guides. Product rate × analysis fraction = nutrient units.

Field planning aid only. Confirm rates with your agronomist, label, and local extension. Not a pesticide or fertilizer recommendation.