GardenCalcs.uk
Watering Can Calculator — How Many Cans for Your Garden
Calculate how many watering cans you need for your garden beds.
Planted area to water, in square metres (length × width)
Capacity of your watering can in litres (a full 10L can weighs about 10kg)
10mm is a good standard soak
Extra water for spillage and runoff (default 1.0)
How We Calculate This
Total water = Area × Water depth (in litres: 1mm on 1m² = 1 litre, so 10mm = 10L/m²).
Cans needed = Total litres ÷ Can size.
Frequently Asked Questions
A good soak is about 10 litres per m² (equivalent to 10mm of rain). Light watering: 5L/m². Deep watering: 15-20L/m².
Yes. Deep, infrequent watering encourages deep root growth. Frequent light watering keeps roots shallow and dependent.
A 10L can weighs about 10 kg when full. Consider using a 5L can if weight is an issue, or use a hose for larger areas.
UK watering cans are commonly 5L, 9L, or 10L. A 9L can is the most versatile. A full 10L can weighs 10kg, which is heavy for extended use.
Most garden plants need about 25mm (25 litres per m²) of water per week. In hot weather this doubles. Newly planted items need more until established.
Related Calculators
Water Pressure Calculator
Calculate water pressure and flow rate for garden irrigation systems.
Water Butt Size Calculator
Calculate the ideal water butt size based on your roof area and rainfall.
Irrigation Timer Calculator
Work out watering duration and frequency for your irrigation system.
Drip Irrigation Calculator
Calculate dripper spacing, flow rates, and pipe lengths for drip systems.
Rainwater Harvesting Calculator
Calculate annual rainwater collection potential from your roof.
Was this calculator helpful?
One tap. Votes are anonymous and carry the page address, your device type, screen size and country, the numbers in the form and the results on screen, so we can check the answer you saw.
Last updated: February 2026
All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.