What a torque-angle spec actually moves
Torque-to-yield fasteners — common on cylinder head bolts — are tightened to a snug torque, then rotated a further specified angle rather than a further torque figure. This works out the actual linear clamp travel that angle produces, from the thread pitch.
| Turn angle | Clamp travel at 1.5 mm pitch |
|---|---|
| 45° | 0.188 mm |
| 90° | 0.375 mm |
| 120° | 0.5 mm |
| 180° | 0.75 mm |
| 270° | 1.125 mm |
| 360° | 1.5 mm |
Getting a number you can act on
- 01Get the thread pitch for the fastener
From the bolt's specification or a size chart — this determines how far one full turn actually advances the fastener.
- 02Enter the specified additional turn angle
From the torque-to-yield specification — commonly 90 degrees, but check the actual service manual figure for the specific application.
- 03Read the additional clamp travel
This is the real physical distance the fastener advances during that angle turn — the number the torque-angle method is actually targeting.
What the calculator is actually doing
Nothing here is proprietary. If you would rather check it by hand, or explain it to someone at a counter, these are the same expressions the tool evaluates.
travel = pitch × (angle ÷ 360)A turn angle is simply a fraction of a full revolution, and a full revolution advances the fastener by exactly one pitch.
Why torque-to-yield uses angle instead of a final torque figure
A torque-to-yield fastener is designed to be tightened past its elastic limit — into the range where it permanently, slightly stretches. That stretch is what produces a very consistent, precisely known clamp load, but it also means the relationship between torque and clamp load stops being predictable once yield begins, because the bolt is no longer behaving elastically.
Torque cannot reliably control the outcome in that regime, which is exactly why the method switches to angle instead. Once yield starts, further rotation produces a known, repeatable amount of additional stretch regardless of the torque required to produce it — which is precisely the property this calculator makes concrete by converting that angle into an actual travel distance.
This is also why torque-to-yield fasteners are generally single-use: the permanent stretch that gives the method its precision means the bolt has already been taken past its elastic range, and reusing it risks yielding further on a second installation with much less predictable results.
Torque Angle Calculator FAQ
How do I calculate torque-to-yield clamp travel?+
Multiply the thread pitch by the turn angle divided by 360. A 1.5mm pitch bolt turned an additional 90 degrees advances about 0.375mm.
Why does torque-to-yield use an angle instead of a final torque?+
Because the fastener is tightened past its elastic limit, where torque no longer predictably relates to clamp load. Angle produces a known, repeatable amount of stretch regardless of the torque needed to achieve it.
Can I reuse a torque-to-yield bolt?+
Generally not recommended. The method relies on permanently stretching the fastener past its elastic range, and reusing it risks yielding further with much less predictable clamp load on a second installation.
What is a typical torque-to-yield angle specification?+
It varies by application, but 90 degrees is common on many cylinder head bolt specifications. Always use the specific figure from the service manual for the application at hand.
Standards and references behind these figures
The arithmetic on this page is fixed, but the boundaries and conventions around it come from published standards and manufacturer guidance. These are the documents they come from, so you can check them rather than take them on trust.
01Dyno correction factors — SAE J1349 against STDExplains the J1349 reference conditions of 77°F, 0% humidity and 29.234 in-Hg, and why STD-corrected figures read higher.↗02Ford Performance — dynamometer testing and engine performance tech tipsManufacturer guidance on dyno correction and how quoted power figures are arrived at.↗A starting point — always check the manufacturer's own specification. Torque figures here come from generic formulas and standard grade tables, not from any specific vehicle's service manual. Critical fasteners — wheels, suspension, engine and safety-related hardware — have a torque specification set by the manufacturer, verified for that exact application, and it takes priority over a generic calculation every time.