Impact Wrench vs Torque Wrench: When to Use Each
Use an impact wrench to remove stuck or rusted fasteners and to run nuts down quickly. Use a torque wrench to tighten anything with a specified torque, such as lug nuts, because it lets you hit the exact number. Most people who work on cars end up using both on the same job.
DEWALT DCF900P1Best overall value
Seesii WH760Best compact kit
JESIMAIK Z1320Lightest kitThe core difference
An impact wrench delivers short, hard rotational blows from an internal hammer. That lets it break loose a seized nut without much effort from you. It is built for speed and force, not for precision.
A torque wrench measures how hard you are tightening. You set a target, pull until the tool clicks, beeps or reads the number, and stop. It does almost nothing for speed, but it is the tool that tells you the fastener is tight enough and not too tight.
Neither one replaces the other. One is a fast, strong driver. The other is a measuring tool.
When to reach for an impact wrench
An impact wrench makes sense when the job is about getting a fastener moving or running it a long way. Fastening torque is how hard the tool tightens. Breakaway torque is how hard it can loosen a stuck nut. Breakaway is usually the number that matters most when you are fighting rust.
Our best impact wrench for the money page notes that for lug nuts, 500 to 700 ft-lbs of breakaway torque is plenty, while trucks and rusted bolts call for more.
- Removing lug nuts, including rusted ones
- Loosening suspension and subframe bolts
- Running nuts and bolts down quickly before the final tightening
- Removing mower blade bolts and similar stubborn hardware
- Repetitive work where a hand wrench would take far too long
When to reach for a torque wrench
Use a torque wrench any time a spec exists. Wheel lug nuts, cylinder head bolts, brake caliper brackets and many engine and suspension parts all have a torque value in the service manual. Too loose and a part can work free. Too tight and you can stretch a bolt, strip threads or warp a part.
Impact wrenches do not give you a reliable final torque. The hammering action means the real tightening depends on trigger time, battery charge, socket and fastener condition. Even with speed settings or auto-stop modes, treat the impact wrench as the tool that gets you close, not the one that finishes the job.
Many click-type torque wrenches also need to be stored at their lowest setting and used with a smooth, steady pull. Follow the maker's instructions for your model.
Using them together: lug nuts as an example
A tire change shows how the two tools fit together. Here is a simple sequence.
- Loosen the lug nuts with the impact wrench while the wheel is still on the ground.
- Raise the vehicle with a jack and support it on jack stands.
- Remove the nuts and wheel, then mount the new wheel.
- Thread each nut on by hand or with the impact wrench on its lowest speed setting.
- Lower the vehicle so the tires touch the ground.
- Finish tightening in a star pattern with a torque wrench set to the vehicle's specified value.
Choosing an impact wrench if you need one
If you decide to buy, drive size and torque are the first filters. Our best 1/2 inch impact wrench page covers the size most people use for wheels and suspension. If you work in tighter spaces or on smaller fasteners, see the best 3/8 impact wrench page.
Power source matters too. Cordless tools are convenient in a driveway. Air tools need a compressor but can be lighter, which our best air impact wrench page explains. For car work, the best cordless impact wrench for automotive page is a good place to start.
Here is how a few 1/2 in cordless models from our data compare on the numbers that matter for this decision.
| Model | Breakaway torque | Weight | Battery included | Warranty |
|---|---|---|---|---|
| DEWALT DCF900P1 | 1400 ft-lbs | 11 lb | Yes | 3 years |
| CRAFTSMAN CMCF940M1 | 1000 ft-lbs | 10.25 lb | Yes | 3 years |
| Seesii WH760 | 738 ft-lbs | 4.4 lb | Yes | Not listed |
| JESIMAIK Z1320 | 900 ft-lbs | 2.98 lb | Yes | Not listed |
| DEWALT DCF900B | 1400 ft-lbs | 6.4 lb | No | Not listed |
Safety notes
Never work under a vehicle supported only by a jack. Use jack stands on firm, level ground. Wear safety glasses, since rust and debris can fly off a spinning socket, and wear hearing protection, because impact wrenches are loud.
Use impact-rated sockets with an impact wrench. Standard chrome sockets can crack under the hammering. Keep fingers clear of the socket and extension, and remove the battery or disconnect air before changing sockets or accessories.
Do you need both?
For occasional jobs like seasonal tire swaps, a torque wrench alone will do the job if you have the time and a breaker bar for stuck nuts. An impact wrench saves effort, but it is not required.
If you work on vehicles regularly, own both. The impact wrench handles the heavy, fast steps. The torque wrench handles the final tightening. That pairing protects your fasteners and your wheels.
Frequently asked questions
Can I use an impact wrench to tighten lug nuts all the way?
It is not recommended. Impact wrenches can overtighten, and the result varies by tool and battery. Use the impact wrench to run nuts on lightly, then finish with a torque wrench.
Can a torque wrench loosen bolts?
Avoid it. Using a torque wrench to break loose tight fasteners can damage its calibration. Use a breaker bar or an impact wrench for loosening.
How often should a torque wrench be checked?
Follow the maker's guidance. In general, avoid dropping it, store it properly and have it checked if it is dropped or gives results you doubt.
Does a lower speed setting make an impact wrench accurate?
No. Lower speed or auto-stop modes reduce the risk of overtightening, but they do not replace a torque wrench when a spec is required.