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Milwaukee M12 and M18 Batteries

Milwaukee Batteries for M12 and M18 Cordless Tools

lithium ion batteries

We get a lot of questions from Milwaukee customers and Milwaukee cordless tools users asking and wondering what batteries are compatible with their M12 and M18 cordless tools. We decided to clear things up for you by answering frequently asked questions about Milwaukee batteries and making a Milwaukee battery guide/cheat sheet (see below) to help you find out what batteries are compatible with your Milwaukee M12 and M18 cordless tools. Spoiler alert: you can use any M12 battery in any M12 tool and any M18 battery in any M18 tool. But we’ll still break it down for you…

M12 Batteries vs. M18 Batteries

The significant difference between the M12 batteries and the M18 batteries are their voltages and power. But lets not also forget to mention other key differences: their tool line comparability, size, and weight.

As mentioned above, M12 batteries are 12V batteries designed for M12 tools only. Other than the voltage difference, there are a few other key differences. For example, M12 batteries are smaller and sleeker, making them well-suited for a person who uses tools but doesn’t require high voltage.

In contrast, the M18 batteries are designed for M18 tools only, making them ideal for extended uses and heavier jobs where power is needed. With its larger design and base it will be a bit heavier, but in the case of how you would be using the tool, a bit more weight would be beneficial.

Shop Milwaukee M12 batteries

Shop Milwaukee M18 batteries

Milwaukee M12 Batteries

3 different M12 compact batteries.

Milwaukee’s M12 Compact and M12 FUEL cordless tools use M12 REDLITHIUM batteries and chargers designed specifically for these Milwaukee M12 cordless tool lines. These batteries are lithium-ion batteries and have an excellent run time, which is up to twice as long as the previous Milwaukee batteries. See our visual battery buying guide to see exact battery tool compatibility.

The M12 batteries come in two different variations, the compact and the high capacity. These batteries were made for durability and superior pack construction, making them perfect for rough jobs while being able to fit in most pockets and bags. Able to perform in climates below 0°F/-18°C, you can get work done no matter what the weather.

Now, both are great for a variety of jobs and are compatible with any M12 tool. The difference between these two batteries is not only the look but the amount of power they offer. The compact battery pack is 65% lighters and 50% smaller than other compact NiCd batteries and offer either 1.5, 2.0, or 3.0 amp-hours of run time.

Then there are the high capacity 3.0, 4.0, and 6.0 amp-hour batteries, allowing for more work for an extended period. So depending on the job and how much space you have in your tool bag or your tool belt you can switch between the batteries to get the best result for your work.

M12 Battery Compatibility

Even though there are a couple different types of M12 tools, you’re able to use ANY M12 battery in ANY M12 tool (as stated above). However, M18 batteries will NOT work with M12 tools. See the visual battery buying guide below for a complete list of M12 compatible batteries.

Milwaukee M18 Batteries

Milwaukee’s M18, M18 FUEL, and M18 HIGH DEMAND cordless tools use M18 REDLITHIUM batteries and

chargers that are specifically designed for the Milwaukee M18 cordless tool line. These batteries are lithium-ion batteries with an insanely efficient runtime and power. See our visual battery buying guide to see exact battery tool compatibility.

There are seven different sizes of M18 Batteries. Those batteries come in three different variations: regular, XC, and High Demand. Even though they are named differently, they are all built with the same durability, and REDLINK Intelligence installed like their M12 counterpart. Able to handle the toughest to the coldest of worksites. The M18 batteries are compatible with any M18 tools and can be swapped out for various jobs, depending on what you need.

You have the CP’s which are the compact M18 batteries and offer either 1.5 or 2.0 amp-hours of runtime. This battery would be for those jobs that need portability and power but don’t need to much time to finish. This battery would be great for the homeowner who needs to drill a few holes into their wall or the starting DIYer.

Next, the XC extended capacity batteries, are for those jobs that need power for long hours. Ideal for on the jobsite tools like your drill, circular saw, or your reciprocating saw, any tool that requires a bit more power to get through harder material. Coming in as either a 3.0, 4.0, 5.0 or 6.0 amp-hour battery, you can adjust your tool to any work demands.

Finally, you have a high demand battery. This specific battery is designed for high draw products and sustained run-time applications. Making this ideal for tools like a table saw, miter saw, or any outdoor power equipment. At 9 amp-hours, this battery maintains full power and pushes cordless tools harder and longer than any other battery. With all that power in your cordless tool, it takes one giant step to complete corded replacement.

In the future, we hope to see Milwaukee release a 15.0Ah battery. That would be ideal!

M18 Battery Compatibility

Again, the beauty of Milwaukee’s M18 cordless tool line is that ANY M18 battery is compatible with ANY M18 cordless tools. That makes life pretty darn easy. See the visual battery buying guide below for a complete list of M18 compatible batteries.

M12 Chargers & M18 Chargers

Three different M18 combo chargers.

Acme Tools offers a wide variety of M12 and M18 battery chargers

including wall chargers, car chargers, multi-battery charger packs, and combo chargers that will charge both types of batteries at once.

Milwaukee Battery FAQ

Are Milwaukee M12 and M18 batteries interchangeable?

No. M12 batteries are designed for M12 tools only, and M18 batteries are designed for M18 tools only.

Can you use M18 batteries with M18 FUEL tools?

Yes. You can use any M18 battery with any M18 tool.

Are M18 batteries interchangeable with M18 tools?

Yes. You can use any M18 battery with any M18 tool.

Are All Milwaukee 18 volt batteries the same?

No. Over the years Milwaukee has had several versions of their 18-volt tools. The most recent categories were 18V Ni-Cd batteries, V18 Li-Ion batteries, and now the current M18 Li-Ion batteries. At this time Milwaukee does not plan to make another platform shift away from M18 batteries.

Can you use M12 batteries with M12 FUEL tools?

Yes. You can use any M12 battery with any M12 tool.

Are M12 batteries interchangeable with M12 tools?

Yes. You can use any M12 battery with any M12 tool.

Milwaukee Battery Buying Guide

Milwaukee Battery Buying Guide


    • Acme Tools

      March 12, 2018 at 8:11 am

      Hello, Thank you for your comment. The M12 and M18 series batteries cannot be interchanged. M12 is how Milwaukee designates their 12 volt tools and M18 is for their 18 volt tools.

      Thank you,
      Acme Tools

  • Martin

    August 25, 2018 at 10:39 pm

    My Milwaukee cordless drill came with M18 Compact REDLITHIUM Batteries. Are these batteries compatible with the MILWAUKEE 2630-20 M18 LI-ION 18V 6-1/2 circular saw (photos only show XC batteries).

    • Acme Tools

      August 27, 2018 at 8:07 am

      Hello, Thank you for your question. The 2630-20 M18 Circular Saw will work on the M18 Compact Batteries. If you are looking for more run time or increased performance we suggest looking into higher Amp Hour (Ah) batteries in the future.

      Thank you,
      Acme Tools

      • martin

        August 29, 2018 at 7:16 pm

        thanks for the answer and I was about to purchase this saw on Amazon but read this post “The Milwaukee saw you are considering requires the Milwaukee 48-11-1828 M18 XC RED LITHIUM 18-Volt battery. NO OTHER battery will work in it including the Milwaukee 48-11-1815 battery; Since it doesn’t have enough amperage Milwaukee has designed the saw to block the smaller battery. BTW the 2630-20 saw is a great saw. I’ve been using mine for several years professionally”. John Nebelsiek on August 29, 2013

        Please can you confirm this Amazon post is incorrect, and that I can run the saw with my 1815 compact batteries.

        • Acme Tools

          August 30, 2018 at 10:01 am

          The Amazon reviewer is incorrect. I personally have installed a 48-11-1815 battery on a 2630-20 circular saw that was on display at our retail location and started the saw. Video is available upon request.

          Thank you,
          Acme Tools

          • Chris

            November 30, 2018 at 8:56 pm

            There is a subtlety here that may be causing some confusion. Back in mid-2010 at Home Depot the Milwaukee representative sold me on a Saturday promotional special consisting of a drill, an impact driver, two batteries and a charger. A great set of tools that have performed very well. The batteries were labeled “M18 LITHIUM-ION”. CAT. NO. 48-11-1815. Only the letter M in “M18” is colored red. The word “RED” is not part of the name on the battery.
            According to Milwaukee’s website the “M18 REDLITHIUM-ION” battery line was introduced at about this time. Both the letter M in “M18” and the word RED in “REDLITHIUM-ION” are colored red. This likely explains the super deal that I got – they were clearing out an earlier battery line.
            As an electrical engineer I can assure you that the old M18 LITHIUM-ION 48-11-1815 will not fit in the new M18 2630-20 cordless circular saw that I just brought home from, you guessed it, Home Depot. There are two ridges on the battery, one of which that lines up with a ridge on the receiver on the saw. I would assume that this is intended to prevent the earlier model battery from fitting onto the saw that is designed to be powered by the newer RED version of the battery. So, a new 48-11-1815 will likely fit but an older version will not.
            Anyway, it’s off to HD tomorrow, yes Saturday, to see if one of the new RED batteries will fit in my old charger or if I have to buy both items.

    • Acme Tools

      June 17, 2019 at 7:54 am

      Hi Rick, Thank you for your question. Milwaukee does not make an adapter to be able to run 18V batteries on their 12V tools.

      Thank you,
      Acme Tools

    • Acme Tools

      September 23, 2019 at 8:50 am

      Hello, Thank you for your question. We do apologize but we do not have information on the UK model and are unable to offer a suggestion.

      Thank you,
      Acme Tools


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