Water Consumption Calculator
Household water use and cost: litres per person per day, the monthly total and where it goes.
Water is usually the smallest utility bill and the easiest one to reduce, because most of it goes on a handful of activities whose consumption is well known: showers, toilets, laundry, dishes and the garden.
Enter the household, the daily habits and your price per cubic metre, and this calculator shows the daily and monthly consumption, the cost and the share taken by showers and laundry.
At a glance
- What you enter
- People in the household, Minutes of shower per person per day, Shower flow rate, Toilet flushes per person per day, Litres per flush, Washing machine loads per week, Litres per wash, Dishwasher loads per week, Litres per dishwasher load, Other daily use for the household, Price per cubic metre
- What you get
- Water used per day, Litres per person per day, Water cost per month, Water cost per year, Cubic metres per month, Share used by showers, Share used by laundry
- Formula shown
- Yes - every step, right below your results.
- Cost and privacy
- Free, no account needed, and nothing you type is stored.
See worked examples ↓ Read the FAQ ↓ Share this calculator ↓
Results are estimates for general information only - always verify with a professional or official source before acting on them.
How to use the Water Consumption Calculator
- 1 Enter People in the household (people)
- 2 Enter Minutes of shower per person per day (minutes)
- 3 Enter Shower flow rate (litres per minute)
- 4 Enter Toilet flushes per person per day
- 5 Enter Litres per flush (litres)
- 6 Enter Washing machine loads per week
- 7 Enter Litres per wash (litres)
- 8 Enter Dishwasher loads per week
- 9 Enter Litres per dishwasher load (litres)
- 10 Enter Other daily use for the household (litres) - Drinking, cooking, cleaning, garden and outdoor taps.
- 11 Enter Price per cubic metre
- 12 Press Calculate. You get Water used per day, Litres per person per day, Water cost per month, Water cost per year, Cubic metres per month, Share used by showers, Share used by laundry, and every intermediate step stays visible under “How is this calculated?”
- 13 Change one number at a time to see what moves the result - that is usually the most useful thing a calculator can tell you.
Worked examples
Real numbers run through this calculator. Open any example to load it into the form above and change it.
A family of four taking eight-minute showers
Four people, 9 litres a minute, five flushes each, five washing loads a week and $4 a cubic metre.
You enter
- People in the household
- 4 people
- Minutes of shower per person per day
- 8 minutes
- Shower flow rate
- 9 litres per minute
- Toilet flushes per person per day
- 5
- Litres per flush
- 6 litres
- Washing machine loads per week
- 5
- Litres per wash
- 50 litres
- Dishwasher loads per week
- 5
- Litres per dishwasher load
- 12 litres
- Other daily use for the household
- 60 litres
- Price per cubic metre
- $4.00
You get
- Water used per day
- 512.29 litres
- Litres per person per day
- 128.07 litres
- Water cost per month
- $61.47
- Water cost per year
- $747.94
- Cubic metres per month
- 15.37 m3
- Share used by showers
- 56.2%
- Share used by laundry
- 7.0%
The household uses 512.29 litres a day, which is 128.07 litres for each of the four people. Over a month that is 15,368.57 litres, or 15.37 cubic metres, costing $61.47, and $747.94 over a year at $4 a cubic metre. Showers take 288 litres, which is 56.2% of the daily total, and laundry 35.71 litres or 7.0%. Toilets add 120 litres and dishwashing 8.57 litres.
A careful couple with a low-flow shower and no dishwasher
Two people, five-minute showers at 6 litres a minute, a dual-flush toilet and $2.80 a cubic metre.
You enter
- People in the household
- 2 people
- Minutes of shower per person per day
- 5 minutes
- Shower flow rate
- 6 litres per minute
- Toilet flushes per person per day
- 4
- Litres per flush
- 4.50 litres
- Washing machine loads per week
- 3
- Litres per wash
- 45 litres
- Dishwasher loads per week
- 0
- Litres per dishwasher load
- 12 litres
- Other daily use for the household
- 40 litres
- Price per cubic metre
- $2.80
You get
- Water used per day
- 155.29 litres
- Litres per person per day
- 77.64 litres
- Water cost per month
- $13.04
- Water cost per year
- $158.70
- Cubic metres per month
- 4.66 m3
- Share used by showers
- 38.6%
- Share used by laundry
- 12.4%
The household uses 155.29 litres a day, or 77.64 litres each, which is under two thirds of the family figure per person. Over a month that is 4.66 cubic metres costing $13.04, and $158.70 over a year at $2.80 a cubic metre. Showers are still the largest single use at 60 litres a day, but their share falls to 38.6%, and laundry is 19.29 litres, or 12.4% of the total.
Guides that go with it
How Much House Can I Afford on My Salary?
You earn a steady salary. You want a house. Somewhere between those two facts sits a number you need to know before you talk to a lender, a seller, or a real estate agent: the top price you can realis…
How Much of Your Salary Should Go to Rent?
You can work out a defensible rent ceiling in about fifteen minutes with nothing more than your payslip and a calculator. By the end of this guide you will know your gross and take-home pay, the rent…
How Much Can You Save by Paying Off Debt Early?
Paying extra toward a loan feels good. But how much does it actually save? In about ten minutes, you can work out the real number for your own debt: how many months you would cut, how much interest yo…
Frequently asked questions
Why is water billed in cubic metres?
A cubic metre is a thousand litres. A household using 300 litres a day goes through one every three days or so, which makes it a convenient unit for a bill: a few units a week rather than tens of thousands of litres.
The calculator does the conversion for you, multiplying the daily litres by thirty for the month and dividing by a thousand before applying your price. Check whether your bill also carries a standing charge or a sewerage charge, because neither is included here.
What shower flow rate should I enter?
An older or unregulated shower head delivers about 12 litres a minute, a standard one around 9, and a modern low-flow head 5 to 7. The figure is often printed on the head or its packaging, and a simple test is to fill a bucket for a known time and measure what you collected.
Shower use is minutes multiplied by flow rate multiplied by the number of people, so both levers matter. Cutting a shower from eight minutes to five saves more than fitting a slightly smaller head, and doing both together is where the largest reduction comes from.
Do the laundry and dishwasher figures need to be weekly?
Yes. Both fields are loads per week, because households count washing that way, and the calculator divides them by seven to spread them across the days. If you know a monthly figure instead, divide it by 4.33 before entering it.
The litres per load depends on the machine and the programme: 40 to 60 litres for a washing machine, and 10 to 15 for a modern dishwasher on an eco cycle, with older models using considerably more. A half load uses most of the water of a full one, so the number of loads matters more than the machine.
Which part of the household use should I attack first?
Read the two share lines before deciding. In most households showers are the largest single use, and a shorter shower or a low-flow head is the cheapest change available. Toilets come next, where a dual-flush or a cistern displacement device costs little and lasts for years.
If laundry shows a large share, washing full loads rather than half loads is the free fix. A leak or a dripping overflow is invisible in a calculation like this and can quietly waste more than any habit change, so check the meter over an hour when nothing in the house is running.