Power Tool Amps, Horsepower and Volts

When buying or using power tools, you’ll often see terms like amps, horsepower, and volts on the packaging or in manuals. But what do they actually mean, and how do they affect performance? This guide breaks it down in plain terms so you know what to look for—and what matters most depending on your needs.

Amps (Amperes)

  • What It Means: Amps measure how much electrical current a corded tool draws.
  • Why It Matters: Higher amps generally mean the tool has more power and can handle heavier tasks.
  • Common Ratings:
    • 6–8 amps: Light-duty tools (drills, palm sanders)
    • 9–12 amps: Mid-range tools (circular saws, routers)
    • 13+ amps: Heavy-duty tools (reciprocating saws, demolition tools)

The circuit your tool is plugged into should support the amp draw. Most home outlets are 15 amps, so don’t overload them.

Horsepower (HP)

  • What It Means: Horsepower is a measurement of work over time—how much a tool can push through material.
  • Why It’s Tricky: Some brands use peak horsepower (a marketing number). You want rated or continuous horsepower for a more realistic idea of performance.
  • Where You See It: Table saws, routers, air compressors, and some heavy-duty stationary tools.

Tip: For tools like routers or table saws, 1.5–2 HP is enough for most tasks. Over 3 HP usually requires a dedicated 240V outlet.

Volts (Cordless Tools)

  • What It Means: Voltage tells you how much potential power a battery can deliver.
  • Why It Matters: Higher voltage = more torque and power. But it also means a heavier tool and battery.
  • Typical Ranges:
    • 12V: Compact, lightweight tools for small tasks
    • 18V / 20V Max: Most common, great balance of power and runtime
    • 36V / 40V / 60V: High-performance tools, often for lawn care or jobsite use

Reality Check: A well-built 18V tool can outperform a cheap 20V tool. It’s not just the volts, it’s the tool’s efficiency and motor design too.

Know Before You Buy

  • More Power = More Demand: High-amp tools need thick, high-quality extension cords. Don’t skimp.
  • Check Your Power Source: If a tool is 240V, make sure you have the right outlet.
  • Don’t Be Fooled by Numbers Alone: Look at how the tool performs under load, not just its printed specs.

Final Thoughts

Understanding amps, volts, and horsepower helps you choose the right tool for the job and the power source to support it. Focus on the application, not just the rating. For example, you don’t need 15 amps to drill a few holes, but you’ll want it for ripping 2x lumber all day. Match the tool to the task and you’ll get better performance and longer life out of your gear.