Garden Watering Calculator
Fill in the values and the answer updates as you type.
How the Garden Watering Calculator works
One millimetre of water over one square metre is one litre, so litres = area × depth (mm). Dividing by efficiency adds the water lost to runoff and evaporation, which is about 25% for sprinklers and 10% for drip lines. Many gardens need roughly 25 mm a week, rainfall included. Example: with the default values, 50 m² needs about 1,667 litres a week.
Inputs and results
The Garden Watering Calculator takes 4 inputs and gives 3 results.
What you enter
- Garden area (m²) — starts at 50.
- Water needed per week (mm) — starts at 25.
- Watering efficiency (%) — starts at 75.
- Watering sessions per week — starts at 2.
What you get
- Water per week (litres)
- Water per session (litres)
- Water per month (litres)
Example: Garden Watering Calculator with the starting values
With garden area 50 m², water needed per week 25 mm, watering efficiency 75 % and watering sessions per week 2, the calculator returns:
| Water per week (litres) | 1,667 |
|---|---|
| Water per session (litres) | 833 |
| Water per month (litres) | 7,242 |
Change any value above and the results update straight away.
Garden Watering Calculator FAQ
How do I use the Garden Watering Calculator?
Enter garden area, water needed per week, watering efficiency and watering sessions per week in the fields, then read water per week (litres), water per session (litres) and water per month (litres) in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Garden Watering Calculator calculate?
Weekly water volume for a garden bed or lawn. It returns water per week (litres), water per session (litres) and water per month (litres) from the 4 values you provide.
What values does the Garden Watering Calculator start with?
It opens with garden area 50 m², water needed per week 25 mm, watering efficiency 75 % and watering sessions per week 2 so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Garden Watering Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Garden Watering Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.