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.
16 responses to “Power Tool Amps, Horsepower and Volts”
I live in Australia which uses 240 v ac if I purchased a ac power tool from the US it would most likely be a 110 V power tool, would I be ok to purchase a tool like the DeWalt 611 router, from the US and be able to use it in Aussi without a power transformer.
Cheers
David James
Good Question. I have no idea on power conversion. I tried to look it up, but can’t find a solid answer.
I have an OSHA inspector who tells us the 15 amp rating on a saw means that is how much amperage it can draw on start up and under heavy load. He says we can not plug two saws into the same circuit on a 20 amp breaker because if both are started at the same time we will overload the circuit heat up the wiring and start a fire. I said I have never had two saws trip a 20 amp breaker. He says we can not trust the breaker. He says we can not plug three tools into a three way outlet beacause we overload the circuit. Is all this true?
Well in theory that is true, I have never seen it enforce. However that is what breakers are for. If you overload the circuit the breaker should trip therefore preventing a fire.
“Volts is the force” “You can think of volts as horsepower” “The higher the volt, the more power”
God this is so utterly wrong. Doesn’t anyone pay attention in science class anymore?
voltage, force, and power are all completely different. Voltage is measured in volts. Force is measured in newtons or lbf. Power is measured in watts or horsepower.
BUT when comparing equipment (drills/mowers) how do you compare when one manufacturer uses amp and another uses volt? This is truly confusing to me as a consumer and makes it difficult to make informed decisions on purchases.
Your right, it does make it hard. There should be a universal measrement.
I am in the process of buying a new table saw that is supposed to recognize whether or not it has a 110 plug or a 220 plug and consequently deliver from 1 3/4 hp to 2 hp with the 220 plug. Based on the previous discussion, this makes no sense to me. Does hp increase with increased volts? The company does not give a definitive answer. Can you help?
The 220 should give more torque, Check out the power tool forums to see if they can answer your question.
NO – Do not attempt to plug in a US 110/120V tool into a 220
/240 50/60HZ electricial outlet with out using a stepdown transformer. To do so will almost certainly destroy the tool in question. Spent 20+ years in the US military traveling around the world, had to run all my US tools on a transformer. Reminds of the time when my sister came to visit me in Europe and almost burned my house down. She had one of those travel plug adapters that she attached to her curling iron. The thing literlly melted before eyes. Oh and I had to throw the breaker switch because it did not trip. Just my two pence worth
Greg
I was looking to buy a bench grinder. The higher priced Baldor 3/4 8″ grinder uses 4.8 amps , the cheaper Westward 3/4 hp grinder uses 8 amps. Which one do you think would have more power. They are both 110 volt @ 3600 rpm
From your numbers the Baldor seems way more efficient and look like a better unit to me.
Thankyou for your reply. I was just thinking that maybe the higher amp usage meant that it might have more power, but it must be just less efficient.
Usually it does mean higher, but they both put out 3/4hp but one draws more amperage, I don’t see where its going unless its torque.
Thankyou very much for your reply.
yw :}