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Calculate hydroponic NPK nutrient mixing ratios and ppm targets for vegetative and flowering stages. Reservoir dosing guide.
Calculate pH Up and pH Down dosing for hydroponic nutrient solutions. Milliliters needed to reach target pH from current reading.
Convert hydroponic EC (mS/cm) to PPM (TDS) and back. Supports 500 and 700 scale conversion factors for all popular nutrient meters.
This tool applies a standard formula from the relevant domain. The computation is deterministic — given the same inputs, the result is always identical. The formula accounts for the primary variables that determine the output.
Days ≈ Reservoir(L) ÷ (Daily uptake L × EC drift factor)The calculation requires: Reservoir Volume, Plant Count, Daily Uptake/Plant, Max EC Drift (%). Each parameter contributes to the final result according to the formula above. Accuracy depends on the precision of your input measurements.
Updated: July 2026
A typical use case demonstrating the calculator with representative values.
→ Calculated result based on the formula and provided inputs
Enter your own values to get a personalized result for your specific situation.
→ Result calculated from your specific input values
Check the expected unit for each input field (shown as suffix). Converting between imperial and metric units before entering values prevents calculation errors.
When a formula combines multiple measurements, all inputs must use compatible units. Convert everything to the same system (metric or imperial) before calculating.
Estimate how often to fully change nutrient solution based on uptake. Free online hydroponics calculator with instant, accurate results. It applies the calculation formula (Days ≈ Reservoir(L) ÷ (Daily uptake L × EC drift factor)). For example: 100 l, 12 plants, 500 ml/plant/day — A typical use case demonstrating the calculator with representative values.