NPK Fertilizer
Read a bag's N-P-K numbers into actual nutrient pounds.
About NPK Fertilizer
Each of the three analysis numbers is read as a percentage of the bag's total weight. The NPK ratio tells you whether a product feeds growth, roots or fruiting, so matching it to the crop matters.
Formula
NPK Fertilizer
Each nutrient = bag weight x its percentage
- 10-5-10
- Bag analysis listing N, P2O5 and K2O percentages
Worked example
With the default values below, NPK Fertilizer returns Nitrogen of 5.00. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Bag weightminimum 1 lb
- 50 lb
- N - Nitrogenaccepts 0–50 %
- 10 %
- P - Phosphorusaccepts 0–50 %
- 5 %
- K - Potassiumaccepts 0–50 %
- 10 %
Results
- Nitrogen
- 5.00 lb
- Phosphate (P2O5)
- 2.50 lb
- Potash (K2O)
- 5.00 lb
- Total NPK
- 12.50 lb
Step by step
- 1Values used
- 2NPK Fertilizer
- 3Nitrogen= 5.00 lb
- 4Phosphate (P2O5)= 2.50 lb
- 5Potash (K2O)= 5.00 lb
- 6Total NPK= 12.50 lb
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is NPK Fertilizer calculated?
Each nutrient = bag weight x its percentage Each of the three analysis numbers is read as a percentage of the bag's total weight.
Why does NPK Fertilizer matter?
The NPK ratio tells you whether a product feeds growth, roots or fruiting, so matching it to the crop matters.
What values do I need to enter?
This calculator takes 4 inputs: Bag weight, N - Nitrogen, P - Phosphorus, K - Potassium. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.