Knowing your typical gas usage is one of the fastest ways to sanity check your bill. It helps you separate two different issues: using more gas than you realised, or paying too much per MJ because your plan or supply charge is no longer competitive.
This guide explains what “average” gas usage looks like in Australia, how to estimate your monthly gas use in megajoules (MJ), and what to do if your usage or costs look high.
How gas usage is measured in Australia
Most residential and small business gas bills in Australia measure usage in megajoules (MJ). Your bill will show your total MJ for the billing period and your average daily usage.
If you want a deeper breakdown of the line items on your bill, see: How to read your energy bill.
Average gas usage per month in Australia (MJ benchmarks)
There is no single national “average” that applies to every home or business because climate, appliances, and whether you use gas for space heating changes everything. As a practical benchmark, many Australian homes fall into one of these usage bands:
- Low usage (cooktop only, or gas hot water with minimal heating): roughly 500 to 1,200 MJ per month.
- Medium usage (gas hot water and cooking, some heating in winter): roughly 1,200 to 2,500 MJ per month averaged across the year.
- High usage (gas ducted heating, older home, colder climate): roughly 2,500 to 4,500+ MJ per month averaged across the year.
Season matters. If you use gas heating, winter months can be several times higher than summer. A household that averages 2,000 MJ per month across the year might still see 3,500 to 6,000 MJ in a cold winter month.
By state: why Victoria is often higher
Victorian households commonly record higher annual gas usage than Queensland or parts of NSW because of colder winters and the prevalence of gas heating. That means your “normal” monthly MJ in Melbourne can look very different to Brisbane.
What affects your monthly gas usage the most
If your usage looks higher than expected, these are usually the drivers:
- Space heating: ducted or wall furnace heating dominates winter usage in southern states.
- Hot water type: older storage hot water systems can be significantly less efficient than modern instantaneous units.
- Property efficiency: insulation, draught sealing, window coverings, and zoning make a large difference.
- Occupancy and habits: long showers, thermostat settings, and hours at home.
- Appliance condition: poorly maintained heaters or hot water units can use more gas than they should.
- Business operations: trading hours, number of covers (hospitality), process heat, or laundry loads.
How to estimate your monthly gas usage (two quick methods)
Method 1: Use your bill’s average daily MJ
Most bills show an average daily usage. Multiply it by the number of days in a month.
- Example: 60 MJ/day × 30 days = 1,800 MJ per month.
Method 2: Convert from your quarterly bill
If you are billed quarterly, divide your total MJ by roughly 3.
- Example: 6,000 MJ for the quarter ≈ 2,000 MJ per month (then adjust for seasonality).
How to estimate your gas bill from your MJ usage
Your total gas bill usually has two main cost components:
- Usage charge: cents per MJ (c/MJ) multiplied by how many MJ you used.
- Daily supply charge: cents per day (c/day) multiplied by days in the billing period.
For a worked explanation of how suppliers calculate charges, see: Business gas and electricity bills explained.
Simple example calculation
- Monthly usage: 1,800 MJ
- Usage rate: 3.5 c/MJ
- Supply charge: $1.10/day
Estimated cost (usage) = 1,800 × $0.035 = $63.00
Estimated cost (supply) = 30 × $1.10 = $33.00
Estimated monthly total = $96.00 (before any fees, discounts, or adjustments).
What is a “normal” gas bill if your usage is average?
Because rates change often and differ by distributor zone, it is more reliable to benchmark both your MJ usage and your cents per MJ than to chase one “average bill” number.
If you want cost benchmarks by customer type and state, see our updated guide: Average gas bill in Australia.
How to tell if your gas usage is high or if your plan is the issue
Use this quick checklist:
- Your MJ is higher than last year for the same season: usage has likely increased, or you have an appliance issue.
- Your MJ is similar but the bill is higher: your unit rate, supply charge, or discounts may have changed.
- Your supply charge is large relative to usage: you may be a low user where daily charges dominate, plan shopping can help.
- Your bill is estimated: your next actual read may correct the amount.
How to reduce your monthly gas usage
- Heat smarter: lower thermostat settings, heat occupied rooms only, and use timers so heating is not running unnecessarily.
- Improve draught sealing: door snakes and seals can materially cut heating load.
- Service appliances: especially gas heaters and boilers, efficiency can drift over time.
- Hot water habits: shorter showers and efficient showerheads reduce MJ quickly.
- Check for leaks: if you suspect a leak, contact your distributor and a licensed gasfitter immediately.
When it is worth comparing gas plans
Consider reviewing your plan if:
- your contract is ending or has rolled onto a higher rate
- you have seen a price rise notice
- your household size or business operations have changed
- your usage is steady but your total bill keeps increasing
Zembl can compare your current gas and electricity rates against a panel of retailers and handle the switching paperwork if you choose to move, with no interruption to supply.
Get a free gas usage and tariff check with Zembl
If you want to know whether your monthly MJ usage is normal and whether your cents per MJ and supply charge are competitive, Zembl can help. Send us a recent bill and we will validate your usage profile and compare available offers for your meter and location.
Next step: contact the Zembl team to request a free comparison.
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