Fertilizer PPM Calculator

About this calculator

Hydroponic and container growers feed plants by dissolving fertilizer in water to a target nutrient concentration measured in parts per million (ppm), since even a small excess can burn roots while too little starves the plant. The dose is calculated from the fertilizer's nutrient percentage on the label (usually nitrogen, as N-P-K) and the water volume: fertilizer weight = (target ppm × water volume) ÷ (nutrient % × 10,000), a formula that converts a label percentage and a target concentration into a real gram or ounce measurement.

This calculator takes your target ppm, water volume, and the nutrient percentage from your fertilizer's label and returns exactly how much to dissolve. Hydroponic growers, greenhouse managers, and hobbyist container gardeners use it to hit precise feeding schedules — such as 150 ppm nitrogen for leafy greens versus 200+ ppm for fruiting tomatoes — instead of eyeballing a scoop per gallon.