Plant Care Unit Converter
Convert pot sizes, watering volumes, temperatures, lux and foot-candles. Clearly distinguishes US and Imperial gallons for plant-care instructions.
Make a care guide’s units match your measuring jug, thermometer, light meter, or pot label.
Choose your inputs and use the button above to get a result.
Choose the right measurement first
Volume conversions use US customary fluid units unless the name explicitly says Imperial. One US gallon is 3.785411784 liters; one Imperial gallon is 4.54609 liters. A US cup here is 236.5882365 mL. For fertilizer labels, use the exact unit on the label and avoid assuming every kitchen cup is the same size.
Pot dimensions are linear measurements. A pot that is twice as wide does not hold twice the soil: volume also depends on depth and taper. Use the potting soil volume calculator when shopping for mix.
Light units have limits
One foot-candle is approximately 10.76391 lux. Both measure illuminance weighted for human vision. This tool deliberately does not convert lux to PPFD because the conversion depends on the spectrum of the light source. Use a quantum sensor or a reliable fixture map for the DLI calculator.
Temperature uses °F = °C × 9/5 + 32. A temperature difference is different from an absolute reading; for example, a 2 °C change is a 3.6 °F change. Inputs below absolute zero and incompatible unit combinations are rejected.
Frequently asked questions
Are the cup and gallon units US or Imperial?
US units are marked US. Imperial gallon is a separate option. The tool does not silently mix the two systems.
Can I convert lux to PPFD?
Not with a universal constant. Light spectrum changes that relationship, so this converter only converts lux and foot-candles.