Plant Watering Calculator

A garden watering calculator estimates how much water plants need based on pot size, plant type, and weather. Overwatering is as damaging as underwatering for most plants

The calculator uses the standard published formula for garden watering. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

This calculator works with centimetres, inches, square metres, percentages. You can enter values in the units shown — the calculator handles all conversions internally.

The core formula is: Pot volume (L) × 10–20% = volume per watering. Each step in the calculation is shown so you can verify the result manually.