Virtual Water

Free Virtual Water calculator with clear step-by-step results.

About Virtual Water

Virtual water is the volume consumed across a product's whole supply chain, which for food and textiles dwarfs household taps. Splitting it into green water from rainfall and blue-plus-grey water from irrigation and pollution matters because only the latter competes with other users.

Formulas

Total virtual water

Litres = mass kg x water footprint per kg

Blue and grey water

Blue + grey = total x (1 - green water share)

Worked example

With the default values below, Virtual Water returns Total virtual water of 77,000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Quantity of productminimum 0 kg: 5 kg
Productone of Beef (15,400 L/kg), Cheese (5,000 L/kg), Rice (2,500 L/kg), Chicken (4,300 L/kg), Wheat (1,800 L/kg), Cotton textile (10,000 L/kg), Vegetables (320 L/kg): Beef (15,400 L/kg)
Share from rainfall (green water)accepts 0–100 %: 80 %
Household direct water use for comparisonminimum 1 L/day: 350 L/day

Results

Total virtual water: 77,000 L
Blue and grey water (irrigation and pollution): 15,400 L
Green water (rainfall): 61,600 L
Days of household direct water use: 220.0 days

Step by step

1Values used
2Total virtual water
3Blue and grey water
4Total virtual water= 77,000 L
5Blue and grey water (irrigation and pollution)= 15,400 L
6Green water (rainfall)= 61,600 L
7Days of household direct water use= 220.0 days

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 1 decimal place, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why distinguish green from blue water?

Green water is rainfall the crop would have transpired anyway. Blue water is abstracted from rivers and aquifers and directly reduces what is available for other uses, so it carries far more scarcity significance.

Are these factors universal?

No - they are global averages. Beef from rain-fed pasture and beef from irrigated feedlots differ by several times, and local water scarcity changes the meaning entirely.