SAE vs Metric Strength Comparison
Printable shop wall chart: SAE vs Metric Strength Comparison. Free letter-size PDF to print and post at the counter; 25 x 36 inch poster version available.
| Inch grade | Tensile (min) | Closest metric class | Tensile (min) | Interchangeable? |
|---|---|---|---|---|
| SAE Grade 2 | 74 ksi (510 MPa) | 4.8 / 5.8 | 420 / 520 MPa | No |
| SAE Grade 5 | 120 ksi (827 MPa) | 8.8 | 800 / 830 MPa | No |
| SAE Grade 8 | 150 ksi (1034 MPa) | 10.9 | 1040 MPa | No |
| ASTM A574 socket | 180 ksi (1241 MPa) | 12.9 | 1220 MPa | No |
Similar strength does not make parts interchangeable: thread form, pitch, head size and nut standards all differ. Never mix inch and metric threads.
These tables carry the same figures as the printed sheet below.
The printed sheet
25 x 36 inch poster version
For the full-size shop poster, tell us where to send it.
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Text version of this sheet
8.8
10.9
12.9
GRADE 5
CLASS 8.8
GRADE 8
CLASS 10.9
12.9 (TYP. SOCKET)
Strength cousins, not substitutes · different threads, dimensions and nut standards
Inch grade
Tensile (min)
Closest metric class
Tensile (min)
Interchangeable?
SAE Grade 2
74 ksi (510 MPa)
4.8 / 5.8
420 / 520 MPa
No
SAE Grade 5
120 ksi (827 MPa)
8.8
800 / 830 MPa
No
SAE Grade 8
150 ksi (1034 MPa)
10.9
1040 MPa
No
ASTM A574 socket
180 ksi (1241 MPa)
12.9
1220 MPa
No
Similar strength does not make parts interchangeable: thread form, pitch, head size and nut standards all differ. Never mix inch and metric threads.
The Fastener App | TheFastenerApp.com
Fastener Guide reference FG-46E44A · thefastenerapp.com/fastener-guide/wall-charts/sae-vs-metric-strength-comparison · © The Fastener App. Reference only — verify the current governing standard, drawing and manufacturer data before specifying or installing.
