If you've been asked for your NMI, you're not alone. It looks like a string of digits (and sometimes letters) tucked into the fine print of an electricity bill. It is also the single most useful code for comparing plans accurately.

Here is what it means, where to find it, and what to use if you have gas instead.

What an NMI is

NMI stands for National Metering Identifier. Energy Made Easy, the Australian government's free comparison site, describes it as a unique number for the electricity connection at your address.

It always has 10 or 11 characters. Most NMIs are numbers only. Some include letters as well. In Queensland, Energy Made Easy notes that an NMI usually starts with two letters followed by nine numbers.

Your NMI stays with the connection at that address. If you move house, the new property has its own NMI. You do not take the old one with you.

Where to find it on your bill

Get out a recent electricity bill, ideally all pages, and start on page 1. Energy Made Easy says the NMI is often near your customer details, and may be labelled:

National Meter Identifier (NMI)

National Metering Identifier

or simply NMI

Retailer layouts differ, so it may sit in a "supply details" or "your electricity" box rather than next to your name. If you cannot see it on the first page, check the second.

The official site also has a simple tip when you type the number in: watch zeros and ones. Do not mix up a 0 with the letter O, or a 1 with the letter I. If the NMI includes letters, the letters O and I are not used.

Example only, based on Energy Made Easy's guide to finding your NMI. This is not a real bill and shows no dollar amounts. The sample NMI 4102000000 is the example used on Energy Made Easy.

It is not the number on your meter

This is the mistake that sends people in circles. The NMI is not the same as the meter number printed on the physical meter on your wall.

Energy Made Easy is clear about that, and so is the AER's glossary: if you are having trouble finding your NMI, call your electricity retailer and ask for it. They can read it from your account.

You do not need to open the meter box to compare plans.

Why the NMI matters when you compare plans

With a valid NMI, Energy Made Easy (for New South Wales, Queensland, South Australia, Tasmania and the ACT) and Victorian Energy Compare (for Victoria) can often pull your actual meter data. That means plans are priced against how you really use electricity, not a generic household average.

Without it, you can still compare by entering usage from a recent bill, but the NMI is the quicker, more accurate path. That is why Bill Ninja asks for it, and why a bill with all pages is more helpful than a photo of the amount due alone.

If you have gas: look for the MIRN

Gas connections have a different identifier. Energy Made Easy calls it a Meter Installation Registration Number, or MIRN. Your distributor assigns it, and retailers use it to identify the gas connection. You will find it on your gas bill.

(Some bills and state guides also describe it as a Meter Identification Reference Number. The important part is the same: it is the gas connection code, not the number stamped on the gas meter itself.)

If you want both electricity and gas checked, send both bills so both identifiers are visible.

A short checklist

1. Open a recent electricity bill and look on page 1, near your customer or supply details.

2. Copy the 10 or 11-character NMI exactly.

3. Double-check 0 and 1 if it is numbers only.

4. Remember it is not the meter number on the wall.

5. For gas, use the MIRN on your gas bill.

6. If you still cannot find it, call your retailer and ask.

Once you have the number, you can compare plans yourself on the government sites — or send the bill to someone who will do that for you.

We can check it for you

Bill Ninja is an independent, tip-based energy bill checker for households and small businesses in New South Wales, Queensland, South Australia, Tasmania, the ACT and Victoria. Send us your electricity or gas bill, we compare it on Energy Made Easy or Victorian Energy Compare, and we email you a plain-English report — usually within about 24 hours. We use no-conditions plans as the headline (no pay-on-time or direct-debit discounts). No upfront fee, no card, no retailer commissions. If we find a saving and you're happy, tip what feels fair.

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