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What is a kWh and how much does one cost?

A kilowatt-hour is the unit your electricity is sold in. Here is what it means, what it costs in Australia, and how to work out your own rate.

By EnergySorted Editorial Team · Updated · 6 min read

A kWh in plain English

A kilowatt-hour, written kWh, is simply the unit of energy your electricity is sold in — the same way petrol is sold in litres. One kWh is the amount of electricity a 1000-watt (1 kilowatt) appliance uses if it runs for one hour. So a 2000W heater running for 30 minutes uses 1 kWh, and a 100W bulb left on for 10 hours also uses 1 kWh.

Your meter counts kWh as they pass, and your retailer charges you a set price per kWh — the "usage rate" on your bill. That rate is measured in cents per kilowatt-hour (c/kWh). Everything you do with power, from boiling the kettle to charging an EV, ends up as a number of kWh on your next bill.

How much does a kWh cost in Australia?

There is no single national price. What you pay per kWh depends on your state, your network area, your retailer and your specific plan. As a broad guide at the time of writing, usage rates across the National Electricity Market (NSW, VIC, QLD, SA, ACT, TAS) tend to sit somewhere in the range of roughly 25c to 40c per kWh, with Western Australia and the Northern Territory sitting outside that market on their own regulated pricing.

Two things make the "real" cost higher than the headline rate. First, the daily supply charge — a fixed fee (often 90c to $1.50 a day) you pay just for being connected, before you use a single kWh. Second, tariffs that charge different rates at different times (time-of-use) or add demand charges. Because of this, the cheapest advertised c/kWh is not always the cheapest plan for you. Always check the current rates on any offer, as they change regularly.

This is exactly the trap EnergySorted is built to see through. Rather than ranking plans on a single headline number, it costs every plan — supply charge, usage rates across peak and off-peak, controlled load and solar feed-in — against your real usage taken from an uploaded bill, so the comparison reflects what you would actually pay.

Work out your own cost per kWh

  1. Find your latest electricity bill and note the total number of kWh used for the period (it is usually shown as "usage" or "consumption").
  2. Note the total usage charge in dollars for that same period (the energy cost, not including the daily supply charge).
  3. Divide the usage charge by the number of kWh. That gives your average cost per kWh. Example: $120 of usage over 400 kWh is 30c/kWh.
  4. To get your true "all-in" cost including the supply charge, divide your whole bill (minus GST and one-off fees) by total kWh — this is what a like-for-like comparison should be based on.

How many kWh do everyday things use?

Boiling a full kettle
Roughly 0.1 kWh — a few cents each time.
A load of washing (cold)
Around 0.3–0.5 kWh; hot washes use much more.
Ducted air conditioning (1 hour)
Commonly 2–5 kWh depending on the size of the system and the temperature.
Electric hot water (per day)
Often 4–8 kWh for a household, frequently on a cheaper controlled-load tariff.
Charging an EV (full charge)
Typically 40–75 kWh depending on battery size — the single biggest new load in most homes.

Frequently asked questions

Is a kW the same as a kWh?

No. A kilowatt (kW) is a rate of power — how fast energy is being used right now. A kilowatt-hour (kWh) is an amount of energy used over time. A 2kW heater running for one hour uses 2 kWh.

What is a good price per kWh?

It varies by state and network, but a competitive usage rate at the time of writing often sits toward the lower end of the roughly 25–40c/kWh range. The only meaningful test is the total cost against your usage, including the daily supply charge, so always compare on your real numbers.

Why is my cost per kWh higher than the rate on my plan?

Because the daily supply charge is spread across the kWh you use. If you use little power, that fixed fee makes each kWh effectively more expensive, which is why low-usage households should watch the supply charge closely.

How many kWh does an average home use?

A typical Australian household uses somewhere between about 15 and 25 kWh a day, though this swings widely with household size, climate, heating type and whether you have solar or an EV.

Does uploading my bill really change the answer?

Yes. Two plans with the same headline rate can cost very differently once time-of-use periods, controlled load and solar feed-in are applied to your actual pattern of use. Costing plans against a real bill is how EnergySorted finds the genuine cheapest option rather than the best-looking advertisement.

See this on your own bill

EnergySorted costs every plan in your area against your actual usage.

General information only, current at the time of writing — not financial advice. Rebate schemes and rules change; always confirm details with your retailer or state government energy site.