UWO (Unit Watts Out)
Affiliate link — we may earn a commissionUWO measures the actual power a tool delivers to the work, after accounting for losses in the motor, gears, and drivetrain. It's different from input watts (what the motor draws from the battery or outlet) because every motor wastes some energy as heat and friction. A tool rated at 500 UWO delivers 500 watts of cutting, drilling, or grinding force at the bit or blade. DeWalt uses UWO as a standard spec across their cordless line. Other brands don't always publish it, which makes cross-brand comparisons harder. When it's available, UWO is a more honest power number than voltage alone.
Why It Matters
Two tools can run on the same 20V battery and deliver very different UWO numbers because of motor efficiency and gearing differences. UWO tells you what actually reaches the cutting edge. It's the closest thing to a fair power comparison across different tool designs.