Commercial gas bills use different units and market identifiers from electricity, but the comparison process should still be straightforward.
This guide explains the bill, the contract and the current market context without inventing a universal “good” gas rate. A defensible comparison uses the site’s real consumption and the complete contract cost.
The short version
- Gas usage is commonly shown in megajoules (MJ) or gigajoules (GJ).
- 1 GJ equals 1,000 MJ.
- The common tariff components are a daily supply charge and a variable usage charge.
- The MIRN identifies the gas supply point in the Queensland retail gas market.
- Some larger or negotiated contracts may also include capacity, metering, network or other service charges.
- AEMO reported east coast wholesale gas averaging $10.61/GJ in Q1 2026, but that is not a retail business tariff.
- Compare offers using the same annual consumption, contract start date and commercial assumptions.
MJ, GJ and the rate on the bill
The Australian Government’s business energy guidance says a gas usage charge commonly appears in cents per megajoule.
The conversion is simple:
| Bill unit | Equivalent |
|---|---|
| 1 GJ | 1,000 MJ |
| 1 GJ | about 277.8 kWh of energy |
| 1 cent per MJ | $10 per GJ |
| 2 cents per MJ | $20 per GJ |
That conversion lets you compare two quotes even when one retailer uses cents per MJ and another uses dollars per GJ.
Example conversion
If a bill shows:
- 35,000 MJ used; and
- a usage rate of 2.1 cents per MJ,
then the energy usage is 35 GJ and the usage component is $735 before daily charges, other fees and GST.
This is an arithmetic example, not a market-price benchmark.
What is a MIRN?
The Meter Installation Registration Number, or MIRN, identifies a gas distribution supply point.
AEMO’s Queensland retail gas procedures require distributors to maintain MIRN information for supply points in their distribution regions. AEMO also describes the MIRN as the Queensland gas-market equivalent of an electricity NMI.
Use the MIRN when:
- asking a retailer to identify the account;
- requesting a gas quote;
- checking whether the correct site is being transferred;
- matching bills across a multi-site portfolio.
The MIRN and gas meter number are different identifiers. Record both when preparing a comparison.
The main parts of a commercial gas bill
Bill layouts vary by retailer. Start with these sections.
Account and supply-point details
Check:
- legal customer name;
- supply address;
- MIRN;
- meter number;
- retailer and distributor shown on the account;
- billing period;
- contract or plan name, if displayed.
One wrong site identifier can invalidate an entire comparison.
Meter readings and consumption
Look for:
- opening and closing meter readings;
- whether the reading is actual or estimated;
- MJ or GJ consumed in the billing period;
- any conversion or heating-value factor shown by the retailer.
If a reading is estimated, compare it with the physical meter or ask the retailer when an actual read will replace it.
Daily supply charge
This is the fixed charge for each day the site remains connected. It is payable even when the site uses little or no gas during the billing period.
Compare the daily charge across the full contract year, not one short bill.
Variable usage charge
This is the consumption component in cents per MJ or dollars per GJ. Convert all quotes to one unit before comparing them.
A low usage rate can be offset by a high daily charge, and the reverse can also be true. Total annual cost matters more than either line in isolation.
Network, metering and capacity treatment
The AER explains that gas bills are made up of wholesale costs, retail costs and network charges. Retailers decide how underlying network tariffs appear in retail prices.
Depending on the site and contract, the bill may show:
- network charges separately;
- network costs bundled into another rate;
- metering or service charges;
- a capacity or maximum-demand component for a larger negotiated site;
- environmental products selected by the customer.
Do not assume a line is negotiable or non-negotiable from its label alone. Check the price schedule and the retailer’s treatment in the contract.
GST and billing adjustments
Confirm whether quoted rates include or exclude GST. Also separate genuine consumption charges from credits, estimated-reading reversals and prior-period adjustments.
Current wholesale gas context
AEMO’s Quarterly Energy Dynamics for Q1 2026 reported:
- east coast wholesale gas averaged $10.61/GJ;
- Q1 2025 averaged $13.26/GJ;
- Q4 2025 averaged $12.68/GJ;
- March 2026 averaged $9.22/GJ.
AEMO attributed the quarterly result partly to lower demand, including lower gas-fired electricity generation.
This does not mean a commercial customer should receive a retail quote at $10.61/GJ. A retail contract can include network costs, metering, operating costs, risk, margin and the retailer’s view of future supply conditions.
The longer-term supply picture
AEMO’s 2026 Gas Statement of Opportunities says near-term supply adequacy improved to 2029 due to increased supply capability, infrastructure investment and moderating consumption forecasts. It also says new investment is required from 2030 onwards.
That mixed picture is why one quarter of wholesale prices should not drive a multi-year contract decision by itself.
Is there a “good” commercial gas rate?
Not without the rest of the bill.
A gas offer can only be judged after confirming:
- annual usage and seasonal pattern;
- supply address and network position;
- daily charge;
- variable rate;
- network and capacity treatment;
- metering and service fees;
- contract start date and term;
- price-change or indexation clauses;
- exit and rollover terms;
- whether GST is included.
A universal threshold such as “anything above $X/GJ is expensive” ignores too many variables to be reliable.
Which retailers should quote?
AEMO’s gas retail markets allow licensed retailers to sell natural gas to residential and business customers in Queensland and other participating jurisdictions.
That does not mean every licensed retailer will quote every commercial site. Eligibility can depend on:
- the distribution area;
- customer class;
- annual volume;
- credit requirements;
- requested start date;
- meter and data availability;
- the retailer’s current appetite.
Ask for a written list of retailers approached, offers received and retailers that declined. Avoid static “best gas retailer” lists unless they show current comparable evidence for the same site profile.
Bundling gas and electricity
A bundle can simplify account management, but it is not automatically cheaper.
Compare:
- best credible standalone gas offer;
- best credible standalone electricity offer;
- combined bundle offer;
- total annual cost for each option;
- whether leaving one fuel changes the price or exit terms for the other;
- whether contract end dates remain aligned.
Choose the bundle only when the combined cost and commercial terms win on the same assumptions.
How to compare commercial gas quotes
1. Build a 12-month usage baseline
Use a full year where possible so the comparison includes seasonal changes. For multiple sites, keep each MIRN and usage profile separate before creating a portfolio total.
2. Confirm the contract position
Record the end date, notice requirement, exit terms and what happens after expiry. Ask the current retailer to confirm these points in writing if the bill is unclear.
3. Issue one consistent request
Give every eligible retailer the same:
- MIRN and supply address;
- annual and monthly usage;
- required start date;
- contract-term options;
- billing and reporting requirements;
- request for all fees and pass-through treatment.
4. Model total annual cost
Apply each quote to the same consumption profile. Include daily, usage, network, capacity, metering, service and tax treatment.
5. Compare the contract, not just the rate
Check price-change clauses, exit provisions, rollover treatment, volume tolerances and any bundle dependencies.
6. Record the decision and next review
Keep the comparison and signed contract, verify the first bill, then diary the next review well before expiry.
Multi-site gas portfolios
For a multi-site hospitality, property or industrial portfolio, create a gas register containing:
- site name and address;
- MIRN and meter number;
- retailer;
- annual GJ;
- daily and usage rates;
- any capacity or service charges;
- contract end date and notice period;
- planned opening, closure or electrification work.
Do not assume sites can all be priced identically. Compare portfolio and site-level costs so one poor site does not hide inside a good total.
See the multi-site energy contracts guide for the wider procurement process.
New connections and electrification
For a new gas connection, confirm the local network, connection requirements, meter process and retailer responsibilities before committing to a project timeline. Lead times and customer contributions depend on the site and scope.
If considering a switch from gas to electric equipment, compare capital cost, electrical capacity, demand impact, maintenance, operating profile and emissions goals. An energy bill alone is not enough to design the project.
Sources and methodology
Primary sources used in this guide:
- Australian Government business energy guidance
- AEMO Queensland gas retail procedures and guides
- AEMO gas retail markets
- AEMO Quarterly Energy Dynamics, Q1 2026
- AEMO 2026 Gas Statement of Opportunities summary
- AER explanation of wholesale, retail and network gas-cost components
Smarta Switch has separated published market facts from practical procurement commentary. No generic retailer ranking, price threshold or savings percentage is presented as current market fact.
If you want the guide applied to your actual account, upload the latest gas bill or email hello@smartaswitch.com.au. We will identify the units, charges and contract questions before discussing any switch.
Joe Lawrence, Co-founder, Smarta Switch Australia