About the BatteryFits Desk

Cordless tool batteries are one of the most confusing corners of the tool aisle. Brands ship half a dozen packs per platform, capacities and part numbers look alike, and aftermarket sellers flood the search results with packs that may or may not actually fit or hold up. Buy the wrong one and you're either stuck with a battery that won't seat in your tool, or one that fits but comes with tradeoffs nobody warned you about.

BatteryFits exists to answer one question before you spend money: does this pack actually fit your platform, and what are you trading off if you go aftermarket instead of genuine? We map platform compatibility — Milwaukee M12/M18, DeWalt 20V MAX/FlexVolt, Ryobi ONE+/40V, and more — so you know what crosses over and what doesn't before you click buy.

We are not a testing lab, and we don't pretend to be. We source real product data, verify platform fit, and are direct about where genuine and aftermarket packs diverge on warranty and risk.

We don't bench-test cells or measure runtime. Here's what we actually do check before a product earns a spot on this site:

• ✓Platform fit — which tools a given pack physically and electrically fits
• ✓Genuine vs aftermarket — whether a listing is OEM or a third-party replacement, stated plainly
• ✓Stated capacity — the Ah rating as published by the seller, not a lab measurement
• ✓Live availability — whether the listing is currently in stock and priced through Amazon's catalog
• ✓Warranty and risk — what coverage you get (or give up) with each option