How to Compare Cordless Tool Battery Prices

Sticker price and amp-hours both mislead a little if you read them alone. Price per amp-hour is the fair way to compare packs that share the same voltage.

November 11, 2026

If you shop for a cordless tool battery the way most people do, you look at the price, maybe glance at the amp-hour rating, and pick whatever seems cheaper or bigger. That is how you end up with a two-pack that looks expensive but is actually a better deal, or a compact pack that looks cheap until you notice how little runtime you bought.

Don’t compare the number on the price tag alone

Two official packs can sit next to each other with very different prices and still be the same kind of product: an 18-volt battery for one brand’s tools. The difference is often capacity, or how many batteries are in the box. A lower-priced pack is not automatically a better buy than a higher-priced one. If the more expensive listing is two 5Ah batteries and the cheaper listing is one 2Ah battery, you are not comparing the same amount of capacity.

Looking only at amp-hours has the opposite problem. A bigger number usually means more runtime, but it also usually means more money and more weight. You cannot tell from the Ah rating alone whether you are paying a fair price for that extra tank.

What price per amp-hour actually tells you

The fair comparison is price per amp-hour, written in the table as $/Ah. Amp-hours measure how much charge the pack holds. Think of them as the size of the tank. Divide the price by the total amp-hours, and you can see which listing gives you more capacity for the money. Lower is more battery for what you spend.

The math is straightforward: take the price, then divide by amp-hours times the number of batteries in the package. A 5Ah pack sold as a single is just price divided by 5. A 5Ah two-pack is price divided by 10, because you are buying ten amp-hours in total. A four-pack works the same way. If you only divide by the number printed on one battery, a multi-pack will always look worse than it is.

A worked example helps, with round numbers that are not a live listing. Suppose one option is $80 for a single 4Ah battery, and another is $120 for two 5Ah batteries. The first is $20 per amp-hour. The second is $12 per amp-hour. The two-pack costs more at the register, and it is the better capacity deal if you will actually use both batteries. If you only needed one spare, that cheaper single might still be the right buy. Unit cost is how you compare. It is not an order to buy the biggest bundle.

Two-packs only help if you will use both

Retailers like to sell batteries in twos and fours because the package price looks like a promotion, and sometimes it is. The table already spreads that price across every amp-hour in the box, so you do not have to do the arithmetic by hand. What the table cannot tell you is whether a second battery is useful to you.

A second pack is useful if you can leave one on the charger while you keep working, or if you want a spare in the truck. If you have one tool and you pick it up a few weekends a year, a two-pack can be more battery than you will wear out. In that case, a fairly priced single in a size you like may be the more sensible purchase, even if its price per amp-hour is a little higher.

Why these five platforms can be compared this way

You can use price per amp-hour across DeWalt 20V MAX, Milwaukee M18, Makita 18V LXT, Ryobi 18V ONE+, and Craftsman V20 because they all run at the same nominal voltage: 18 volts. Nominal just means the everyday figure, not the higher number you might see for a moment after a charge. DeWalt and Craftsman use marketing names that say 20V. Milwaukee, Makita, and Ryobi just say 18V. Inside, a pack like this is typically five lithium cells in series. Each cell is about 3.6 volts in normal use, which adds up to 18 volts, and about 4.0 volts fresh off the charger, which adds up to 20 volts. The label difference is not extra power by itself, so amp-hours can be compared directly.

Price per watt-hour, written as $/Wh, is the cleaner comparison if you ever mix voltages, because a watt-hour folds voltage and capacity into one figure. On this table, when a watt-hour rating is not listed, $/Wh is estimated from 18 volts times amp-hours and marked as estimated. For these five platforms, sorting by $/Ah is enough. If you want the naming story in more detail, there is a separate guide on DeWalt 20V versus 18V.

That still does not mean you should buy a Milwaukee pack for a Ryobi tool because the unit price looks better. The batteries are not interchangeable across these brands. Filter to the platform you already own, then compare.

How to read the table

The price table starts sorted by $/Ah, lowest first. Set the platform filter before you get attached to a low number on a battery you cannot use. You can also filter by output if you only want standard packs, or only high-output ones. Click a column header if you would rather sort by price or capacity.

A few labels are easy to misread. “From $X” means more than one official option starts at that amount. The price Amazon shows at checkout is the one you pay. Tax and shipping are not included, and prices change. The table only lists official new bare packs: no kits that throw in a charger or a tool, no used or renewed listings, and no third-party batteries. Kits are left out on purpose, so a battery-only price is not being compared with a starter kit that happens to include a pack.

A high-output pack is not a bigger pack

Labels such as High Output, Milwaukee Forge, and DeWalt POWERSTACK describe how hard a pack can deliver current, not how much capacity it holds. A 5Ah POWERSTACK pack and a 5Ah standard pack hold a similar amount of charge. The premium is usually output, and the price that comes with it.

That matters when you sort by $/Ah. A high-output pack can look worse on unit cost and still be the right purchase if you run a saw, grinder, or rotary hammer that bogs down on a standard pack. For a drill, driver, or work light, it often is not worth the extra money. There is a separate guide on that choice. Check the capacity column for tank size, and the output column for the class.

Once you know your platform, open the table, set the filter, and leave the sort on price per amp-hour. That is the comparison that holds up when two packs look nothing alike on the shelf.