18V vs 20V: it's the same battery

Here's the industry's worst-kept secret: DeWalt's "20V MAX" is 18 volts. So is Craftsman's "V20." They measure the maximum voltage of a fully charged pack (about 20V with no load); Milwaukee, Makita, Ryobi, and Bosch measure the nominal voltage under load (18V). Both describe the exact same 5-cell lithium-ion configuration.

So the number on the box means nothing?

For comparing across brands, yes — it means nothing. A "20V" DeWalt is not inherently more powerful than an "18V" Milwaukee. Within one brand's lineup, higher voltage platforms (like 36V/60V lines) do mean more power, but 18V vs 20V MAX is pure labeling.

What actually determines power

• Motor design — brushless motors deliver more usable power than brushed ones of the same size.
• Current delivery — the battery's ability to sustain high amps under load matters more than its voltage label.
• Gearing — this is why torque specs exist. They still aren't perfectly comparable (see the UWO problem below), but they beat voltage for ranking power.

The UWO problem

DeWalt and Craftsman rate drills in UWO (Unit Watts Out), a combined power figure. Everyone else uses in-lbs of torque. There is no honest conversion between them, so cross-brand torque shootouts that mix UWO and in-lb numbers are fiction. Our comparison table labels the unit on every row so you can see which numbers are actually comparable.