A bolt torque chart provides the recommended tightening torque for fasteners by size and grade, ensuring proper clamping force without over-stressing or breaking bolts. SAE bolts (Grade 2, 5, 8) and metric bolts (Class 8.8, 10.9, 12.9) each have distinct torque requirements that depend on bolt diameter, thread pitch, and material strength. Using correct torque values is critical for mechanical assemblies, automotive repairs, and structural connections.
Dry fasteners only. Values are for clean, dry, unlubricated fasteners. Reduce by ~25% when using oil, grease, or anti-seize. Always follow manufacturer specs for critical applications.
SAE Bolt Torque Specifications
Values in ft-lbNo bolts match your search.
SAE Grade Markings
Metric Class Markings
Torque Wrench Tips
How to Use the Bolt Torque Chart
This bolt torque chart gives you fast access to torque specifications for SAE and metric fasteners. Whether you are torquing lug nuts on a car, assembling equipment, or working through a repair manual that lists torque in N-m while your wrench reads ft-lb, this reference has you covered.
Step 1: Select SAE or Metric
Click the SAE (Imperial) tab for standard North American bolts sized in fractions of an inch (1/4", 3/8", 1/2", etc.), or the Metric tab for ISO bolts sized in millimeters (M6, M10, M16, etc.). The table and column headings update instantly to show the appropriate grades or property classes.
Step 2: Choose your unit — ft-lb or N-m
Toggle between ft-lb (foot-pounds) and N-m (Newton-meters) using the unit selector. All values in the table are converted automatically using the factor 1 ft-lb = 1.3558 N-m. Values shown in N-m are rounded to the nearest whole number. This is especially useful when working from a metric service manual but using an imperial torque wrench (or vice versa).
Step 3: Search for a bolt size
Type a bolt size into the search box — such as 3/8, 1/2-13, or M10 — to instantly filter the table. The search is case-insensitive and matches partial strings, so M1 will match M10, M12, M14, M16, M18.
Step 4: Sort columns for quick comparison
Click any column header to sort the table by that column — once for ascending, again for descending. This is useful for finding all bolts that require a specific torque value, or for comparing torque requirements across grades for the same diameter.
Understanding SAE grades
SAE grades are indicated by radial lines on the bolt head. Grade 2 has no markings and is used for non-critical applications. Grade 5 has three lines and is the most common automotive grade. Grade 8 has six lines and is used in high-stress applications like suspension components. Always match your torque spec to the correct grade — applying Grade 8 torque to a Grade 2 bolt will likely break it.
Understanding metric property classes
Metric bolts have their property class stamped directly on the head. Class 8.8 is the workhorse of metric fasteners — general machinery and automotive. Class 10.9 is used in high-load applications. Class 12.9 is the strongest metric fastener class and should only be used where the joint design specifically calls for it. Torque values increase significantly with each class.
Dry vs. lubricated fasteners
All torque values in this bolt torque chart assume clean, dry, unlubricated threads and bearing surfaces. When applying thread lubricants, anti-seize compound, or oil, the reduced friction means less torque is needed to achieve the same clamping force. Reduce torque values by approximately 20–25% when using lubricants. Failure to do so can over-stress and snap the fastener. The rule of thumb: dry spec × 0.75 = lubricated spec.
FAQ
Is this bolt torque chart free to use?
Yes, this bolt torque chart is completely free. It runs entirely in your browser — no signup, no account, and no data sent to any server. Bookmark it for quick jobsite reference anytime.
What is the difference between SAE Grade 2, Grade 5, and Grade 8 bolts?
SAE grades indicate the tensile strength of a bolt. Grade 2 is the weakest, made from low-carbon steel with minimal markings. Grade 5 is medium-strength (made from medium-carbon steel, three radial lines on the head). Grade 8 is high-strength (medium-carbon alloy steel, six radial lines), requiring higher torque and used in demanding applications like automotive suspensions.
What do metric bolt classes 8.8, 10.9, and 12.9 mean?
Metric bolt property classes describe tensile strength and yield ratio. Class 8.8 means minimum tensile strength of 800 MPa and yield strength at 80% of that — the most common grade for general use. Class 10.9 is high-strength (1000 MPa tensile), and Class 12.9 is the strongest class (1200 MPa tensile), comparable to SAE Grade 8 or higher.
Should I reduce torque values for lubricated bolts?
Yes. The torque values in this chart are for dry, unlubricated fasteners. When using oil, grease, or anti-seize compounds, reduce the torque by approximately 20–25% to achieve the same clamping force. Over-torquing a lubricated fastener can stretch or break the bolt. Always follow the manufacturer's specification when available.
How do I convert ft-lb to N-m?
Multiply ft-lb by 1.3558 to get N-m (Newton-meters). For example, 100 ft-lb × 1.3558 = 135.58 N-m. To go the other way, divide N-m by 1.3558 (or multiply by 0.7376) to get ft-lb. The toggle on this chart does the conversion automatically so you can work in whichever unit you prefer.
Are these torque specs for fine thread or coarse thread bolts?
The values in this chart are for coarse thread (UNC for SAE, standard metric pitch). Fine thread bolts (UNF for SAE) can typically handle slightly higher torque values due to greater thread engagement per inch. For fine thread specs or critical applications, consult the fastener manufacturer's data or an engineering handbook.
What is the best torque wrench to use?
For most workshop and mechanical use, a click-type torque wrench is recommended — it signals audibly when the target torque is reached. Beam torque wrenches are reliable and inexpensive but require watching the indicator during tightening. Digital torque wrenches offer the most precision. Always calibrate your torque wrench regularly, and never use an extension bar unless you recalculate the effective torque.
Can I use these torque values for automotive applications?
These general torque specifications are a useful starting point, but automotive manufacturers publish specific torque values for each fastener in service manuals. Always use the manufacturer's torque spec for critical components like cylinder heads, wheel lug nuts, brake calipers, and suspension parts. General charts are best for non-critical fasteners or when OEM data is unavailable.