Guides
How to Choose the Right Bolt Grade for Your Project
Not all bolts are created equal. Two fasteners can look identical yet perform very differently under load — and choosing the wrong grade is one of the most common (and most dangerous) mistakes on a job site. This guide breaks down what bolt grade means and how to pick the right one.
What bolt grade actually measures
A bolt's grade describes its tensile strength — the amount of pulling force it can withstand before it breaks. Higher grades mean stronger bolts, but strength isn't the only factor; ductility, hardness and corrosion resistance all matter depending on the application.
For metric bolts, the grade is shown as two numbers stamped on the head, such as 8.8, 10.9 or 12.9. The first number relates to the ultimate tensile strength, and the second to the yield strength as a proportion of that. An 8.8 bolt, for example, is the workhorse of general construction and steelwork.
Matching grade to the job
For everyday structural and construction work, grade 8.8 is usually the right balance of strength and cost. Where higher loads or critical joints are involved — heavy machinery, load-bearing steel connections — grade 10.9 or 12.9 may be specified by your engineer.
Never substitute a lower grade for a higher one to save cost. If a drawing calls for 10.9, an 8.8 bolt can fail well below the design load. When in doubt, confirm the grade with the project engineer before ordering.
Don't forget the nut and washer
A high-grade bolt is only as strong as the nut it threads into. Always pair bolts with nuts of a compatible grade, and use the correct washers to spread load and prevent loosening. Our team can help you specify a complete, correctly matched assembly.
Need the right hardware for your project? Our team is ready to help.
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