How to use a torque wrench (and how it works)
In this guide
- How does a torque wrench work?
- How to use a torque wrench, step by step
- Using extensions, adapters and crowfoot wrenches
- Types of torque wrenches
- How accurate is a torque wrench?
- Storage and calibration
- Torque wrench vs other wrenches
- How to choose a torque wrench
- If that didn't work
- What you'll need
- Questions people ask
A torque wrench is a wrench that tightens a nut or bolt to a set amount of twisting force, called torque. You set the number, pull until the wrench signals, and stop. That gets the bolt as tight as the maker wants: no looser, no tighter.
This guide is part of our hand tools hub. For the other wrenches in the box, see types of wrenches.
How does a torque wrench work?
Torque is force times distance. Pull with 10 pounds of force on a handle 1 foot from the bolt, and you make 10 foot-pounds (ft-lb). A torque wrench measures that and tells you when you reach the number you set.
A click wrench has a spring inside the handle. The spring presses a small block against a seat in the head. Turning the handle squeezes the spring, which raises the setting.
When your pull beats the spring, the block tips over. Stahlwille describes it as a block that moves from rest to a tilted spot, which gives a click you hear and feel.
The click doesn't stop the wrench. It only tells you to stop. If you keep pulling, the bolt keeps tightening.
How to use a torque wrench, step by step
These steps follow TEKTON's micrometer manual. Most click wrenches work the same way, but read your own manual first.
1. Find the spec and pick the wrench
Look up the torque spec in the owner's or service manual. Pick a wrench whose range covers it. CDI advises using a wrench in the middle 50% of its range, where it is most accurate.
2. Set the torque
- Unlock the handle. On TEKTON's wrench, you pull the locking collar down and hold it.
- Turn the handle until its top edge lines up with the main-scale mark closest to your number.
- Fine-tune with the small micrometer scale on the handle.
- Let go of the collar. Twist the handle both ways to make sure it's locked.
3. Fit the socket and grip the handle
Put the socket on the drive square and seat it fully on the nut.
Hold the handle where the maker marks it. TEKTON puts a groove in the knurling for your middle finger. CDI says to hold the center of the grip. Holding it in the wrong spot changes the reading.
4. Pull slowly at a right angle
Pull the handle at 90° to the wrench, with smooth, even force. Always pull toward you. Don't push, and set your feet so you won't fall if the bolt gives. Don't lean your body weight on it.
5. Stop at the click
Stop the moment you hear or feel the click. TEKTON warns that pulling too fast can carry you past the setting. Take extra care at low settings, where the click is soft.
6. Back it off and put it away
When you're done, turn the handle down to the lowest number marked on the scale. Don't go below it. Store it clean and dry, in its case.
Using extensions, adapters and crowfoot wrenches
A straight socket extension that sits in line with the drive doesn't change the reading. Anything that moves the bolt out past the drive square does. A crowfoot wrench is the common one.
TEKTON gives this fix. Set the wrench to T2 = T1 × L ÷ (L + C):
| Letter | What it means |
|---|---|
| T1 | The torque spec for the bolt |
| L | The wrench's working length, from the drive to your hand position |
| C | How far the crowfoot reaches past the drive (minus if it points back) |
| T2 | The number to set on the wrench |
TEKTON's own example: a 110 Nm spec, a 408 mm wrench, and a crowfoot adding 28 mm. You'd set the wrench to about 102.9 Nm. If the crowfoot points back toward you, the number goes up instead.
No correction is needed if the crowfoot sits at a right angle to the handle.
Never slip a pipe over the handle for more leverage. CDI warns that a cheater bar gives a false reading and can damage the wrench.
Types of torque wrenches
| Type | How it signals | Good for | Watch out for |
|---|---|---|---|
| Click (micrometer) | A click and a small jolt | Most car, bike and shop work | Must be stored at its lowest setting |
| Beam | A needle points to a scale | Cheap checks; no spring to wear | You must read the scale while you pull |
| Dial | A needle on a round gauge | Careful, slow work | Bulky; can be hard to see |
| Digital (electronic) | Beep, light or buzz, plus a readout | Easy reading; many show Nm and ft-lb | Needs batteries; costs more |
| Split beam | A click, from a beam instead of a coil spring | Shops that set many torques a day | Check its manual for storage rules |
How accurate is a torque wrench?
The makers give the numbers:
- TEKTON rates its 24330 click wrench at ±4%. It says it calibrates to ASME B107.300-2010 and checks each wrench at 20%, 60% and 100% of its range. Its newer micrometer manual says ±3%.
- GEARWRENCH rates its 85063M at ±3% clockwise, across 20 to 100% of the range. It says the wrench meets ASME B107.300.
ASME B107.300 is the US standard for hand torque tools and torque testers. At ±4%, a wrench set to 100 ft-lb should deliver between 96 and 104 ft-lb.
Storage and calibration
- Store at the lowest marked setting. TEKTON says this takes the load off the spring so it doesn't tire. CDI and GEARWRENCH say the same. Don't wind it below that mark.
- Exercise it after a long rest. TEKTON says to click it a few times at a low setting so the grease spreads.
- Wipe it clean. Never dunk it in solvent. TEKTON warns that liquid can harm the inside.
- Keep it in its case. Don't toss it loose in a drawer where heavy tools can hit it. Our guide on how to organize a toolbox shows where cased tools go.
- Recalibrate. CDI says once a year or every 5,000 cycles, and after any drop. TEKTON says to test it before use if it has been dropped.
Torque wrench vs other wrenches
| Tool | Use it to | Don't use it to |
|---|---|---|
| Torque wrench | Tighten to a spec | Loosen stuck bolts |
| Breaker bar | Break tight bolts loose | Tighten to a spec |
| Ratchet | Spin bolts on and off fast | Measure tightness |
| Impact wrench | Remove lug nuts and big bolts fast | Final tightening to spec (unless the tool is made for it) |
Odd-shaped wrenches have their own jobs. A basin wrench reaches faucet nuts. A spanner nut needs pins or a hook, as in how to remove a spanner nut without a wrench.
How to choose a torque wrench
- Match the range to your jobs. Your common specs should sit in the middle of the scale.
- Pick the drive size. A 1/4-inch drive is for small bolts in inch-pounds. A 3/8-inch drive covers many car and bike jobs. A 1/2-inch drive is for lug nuts and suspension.
- Get the units you need. Most wrenches show ft-lb and Nm. One ft-lb is 1.3558 Nm, per TEKTON.
- Look for a calibration certificate with a serial number.
- Pick sockets that fit well. See 6-point vs 12-point sockets.
If you don't have a spec, our bolt torque chart gives typical values by bolt grade and size. A manual's spec always wins over a chart.
If that didn't work
- No click. The setting may be higher than the bolt needs, or the bolt is turning in a stripped hole. Stop and check the threads.
- It clicks right away. The setting is lower than you think. Read both scales again.
- The handle won't lock. On TEKTON's wrench, it only locks on exact marks, not between them.
- Readings feel off. Have it checked at a calibration lab. Don't take it apart; TEKTON says only the ratchet part is user-serviceable.
Need a driver bit instead of a socket? See types of screwdrivers. Most bolts you torque are steel; the steel page covers drilling and tapping it.
What you'll need
- Torque wrench with the right range: Your spec should fall in the middle of the scale
- Sockets that match the drive size: 1/4, 3/8 or 1/2 inch drive
- The torque spec for the fastener: From the owner's or service manual
- A breaker bar or ratchet: For loosening; never the torque wrench
- Clean, dry threads: Or lubricated only if the spec says so
Key takeaways
- A torque wrench tightens a bolt to a set twisting force, so it's tight enough to hold but not so tight it stretches or strips.
- Set it, pull slowly at a right angle, hold the handle where the maker marks it, and stop at the first click. Don't keep pulling.
- Makers rate click wrenches to about ±3 to ±4% clockwise. Tekton and GEARWRENCH cite the ASME B107.300 standard.
- Never break bolts loose with it, and never add a cheater pipe to the handle. Both ruin the reading.
- Store it at the lowest marked setting. CDI says to recalibrate yearly or every 5,000 cycles, and after a drop.
Questions people ask
Why should a torque wrench be used?
Because many bolts have a set tightness. Too loose, and the part can shake free. Too tight, and the bolt can stretch, the threads can strip, or a soft part can crack. A torque wrench lets you hit the number in the manual instead of guessing by feel.
Can you use a torque wrench to loosen bolts?
No. TEKTON's manual says not to use it as a ratchet to break a fastener loose, and CDI says the same. The shock load can knock it out of calibration. Loosen with a breaker bar or ratchet, then use the torque wrench only to tighten.
Should you hear one click or two?
One. Stop pulling at the first click. Pulling again to hear a second click adds more torque and can over-tighten the bolt.
How often should a torque wrench be calibrated?
CDI's guidance is once a year or every 5,000 cycles, whichever comes first, and right away if you drop it. GEARWRENCH backs its wrenches with a 90-day calibration warranty.
Does a click torque wrench work counterclockwise?
Some do. Many click wrenches ratchet both ways but only measure clockwise. Dual-direction models, like TEKTON's micrometer series, tell you to set the lowest value before you switch directions. Check your manual.
Can I use an extension or crowfoot?
A straight socket extension in line with the drive doesn't change the reading. A crowfoot or adapter that sticks out past the drive does. TEKTON gives a formula to correct the setting for that extra length.
Sources
- TEKTON Micrometer Torque Wrenches Product Manual: setting, pulling at a right angle, stop at the click, no breaking loose, storage, off-axis correction formula, ±3%
- TEKTON 3/8 in. drive micrometer torque wrench 24330: ±4%, calibrated to ASME B107.300-2010 at 20, 60 and 100% of range
- CDI Torque: torque safety and proper usage (pull don't push, no cheater bars, middle 50% of range, recalibrate yearly or 5,000 cycles, after a drop; via J&M Test)
- GEARWRENCH 85063M 1/2 in. drive micrometer torque wrench: 20-150 ft-lb, ±3% clockwise, meets ASME B107.300, store at lowest setting
- ASME B107.300-2021: Hand Torque Tools and Torque Testers (scope)
- STAHLWILLE: clicking systems for torque wrenches (how the release block tilts and clicks)
Change log: Nov 6, 2026: Rewritten from two 2024 archive posts (how to use a torque wrench; how does a torque wrench work), merged into one guide. Removed the claim that click wrenches are less accurate than other types; added maker setting steps, accuracy figures, the ASME standard, storage and calibration rules, and the crowfoot formula.
