Npk Fertilizer Blend
Calculator
Results
- Nitrogen content
- 2.5
- Phosphorus content
- 2.5
- Potassium content
- 2.5
Home and garden results
| Nitrogen content | 2.5 |
| Phosphorus content | 2.5 |
| Potassium content | 2.5 |
formula-map diagram
- Nitrogen content
- 2.5
- Phosphorus content
- 2.5
- Potassium content
- 2.5
Home and garden relationship
Formula
nutrient = bag weight × (% ÷ 100)= 2.5
Note
This result uses the values you entered and a simplified planning equation; verify quantities and local requirements before purchasing or building.
More in Home and garden
See all →Frequently asked questions
What do the three N-P-K numbers on a fertilizer bag actually mean?+
They're the guaranteed percentage by weight of nitrogen (N), phosphorus as P2O5 (P), and potassium as K2O (K) in the bag. A 10-10-10 bag is 10% nitrogen, 10% phosphorus, and 10% potassium, with the remaining 70% being filler and other minor nutrients.
How do I blend two fertilizers to hit a target N-P-K ratio?+
The calculator solves for how much of each source fertilizer to combine so their weighted nutrient percentages average out to your target ratio, which is useful when you have, say, a high-nitrogen and a high-phosphorus product and need something in between.
Why would I want a custom blend instead of buying a pre-mixed fertilizer?+
Pre-mixed general fertilizers rarely match what a soil test says your specific soil is missing; blending lets you correct, for instance, low phosphorus without adding more nitrogen than your lawn or garden already has, avoiding the waste and runoff risk of unnecessary nutrients.
What does it mean if my soil test says I need more phosphorus but not nitrogen?+
It means your soil already has adequate nitrogen reserves, so applying a balanced fertilizer like 10-10-10 would oversupply nitrogen while still under-supplying phosphorus; a targeted blend or a phosphorus-heavy product alone addresses the actual deficiency without the excess.
Why is over-applying phosphorus a concern even though it's a needed nutrient?+
Excess phosphorus doesn't move through soil like nitrogen does; it accumulates and can run off into waterways during rain, contributing to algae blooms in lakes and streams, which is why several regions restrict phosphorus fertilizer use on established lawns that don't need it.