Calculating the cost of washing cloth nappies

Want to find out how much it actually costs to wash your child's nappies in your washing machine using your washing routine? Here's some tips to help you work it out.

Information you'll need:

Your washing machine

You can find some basic information on the government's Energy Rating Website, but you can also refer to your machine's manual, or check the manufacturer's website for more specific information (or if it isn't energy rated).
  • the number of litres of water your washing machine uses per washing cycle
  • if you incorporate additional rinse cycles in your routine, the number of litres of water your washing machine uses per rinse cycle
  • how many kWh your washing machine uses per wash - select the kWh appropriate to whether you use cold or hot water
CHOICE Magazine can be a great resource for find out more in depth information about your washing machine.

Water & Electricity Costs

  • on your water bill find out how much you're charged per litre of water used
  • on your electricity bill find how much your electricity company charges you per kWH used
CHOICE used average costs of 22 cents per kWh for electricity and $1.50 per 1000 L for water during their most recent (2012) Washing Machine Review & Comparison.


  • how much your detergent costs and how many loads there are in the box/bottle so you can work out how much a load costs you.

Your routine

  • how many cloth nappy loads you do in a year
  • don't forget to include additional litres of water used for flushing poo (a half flush on most toilets is 3L), or rinsing nappies by hand
  • if you use a clothes dryer you'll need to include the electricity costs associated with this based on your usage (you can find some basic energy information here).

Here's an example comparing Fiona's old 1999 Hoover 5.5L Top Loader with her new 2010 Simpson 7L Front Loader and hot versus cold water cycles assuming the following:
  • nappy only loads
  • a rinse cycle followed by a full wash
  • the use of 3L daily for hand rinsing/flushing
  • use of Rockin' Green detergent
  • calculations based on 22 cents per kWh for electricity and $1.50 per 1000 L for water as per CHOICE
  • the yearly total is based on washing 120 loads of nappies a year
  • unfortunately the cold water energy use figures aren't available for her new washing machine, so while using cold water will reduce the cost (indications are that washing in hot can be up to 10 times higher than washing in cold), we just don't know by how much. Fiona usually washes in cold or warm.
  • every washing machine is different in its water and energy usage and Fiona's old machine was an inefficient water guzzler and her new machine is a large 7L machine, so these examples show the higher side of washing costs - most people will have much lower figures.
  Per Washing Load Figures
  Old Top Loader - COLD Old Top Loader -
New Front Loader
Water Usage      
   Litres per Rinse Cycle 30 30 21
   Litres per Full Cycle 120 120 72
   Extra Litres for rinsing/flushing 9 9 9
   Total 159 159 102
Total cost per load assuming cost of water at $0.0015 per litre $0.24 $0.24 $0.15
Electricity Usage      
   kWh per load 0.18 1.33 0.8767
Total cost per load assuming cost of electricity at $0.22 per kWh $0.04 $0.29 $0.19
Detergent Cost (half as much detergent is required in front loader) $0.45 $0.45 $0.22
Total Cost per Load $0.73 $0.98 $0.57
Number of loads in a year 120 120 120
TOTAL YEARLY COST $87.37 $117.73 $67.90
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