Ryobi One+ batteries are fully compatible with older Ryobi 18V tools, but 18V and 40V systems are not cross-compatible without third-party adapters.
Ryobi tools are a dependable and affordable choice among DIYers and homeowners alike, thanks in large part to the company’s One+ system, introduced in 1996. The One+ line boasts 300 power tools and related equipment, including some new tools to consider in 2025. Perhaps the best feature of the One+ is the system’s 18V lithium-ion battery, which is backward compatible. In fact, the 18V One+ battery fits and works in every 18V tool the company has manufactured to this point.
Not only could you continue using your favorite tools with 18V One+ batteries, despite how old they are, you can also keep working even when a battery goes dead. Just grab another 18V battery from any other Ryobi tool, pop it in, and you’re good to go. This interchangeability, while nothing new among many power tool brands, is just an added bonus to Ryobi’s backward compatibility.
By comparison, the batteries for Makita’s XGT system are interchangeable, but they’re not backward compatible with the company’s older LXT line of power tools.
