Tensile Strength Calculator
Enter a force and a cross-section (diameter, width × thickness, rebar or bolt size) to get tensile stress in MPa and psi, compare it with the yield and ultimate strength of steel, aluminum, bolts and more, and see the load at yield and at break.
Tensile stress σ = F ÷ A.
Use the Tensile Strength Calculator
Input Parameters
Area in mm²
Enter a force and a cross-section, then click Calculate.
Tensile strength of common materials — yield vs UTS
Yield strength, ultimate tensile strength (UTS), Young's modulus and elongation at break. Steels and fasteners show specification minimums (ASTM A36, A992, A615, A240, SAE J429, ISO 898-1); the others are typical handbook values. Use certified mill or supplier values for design.
| Material | Basis | Yield MPa (ksi) | UTS MPa (ksi) | E (GPa) | Elongation % |
|---|---|---|---|---|---|
| A36 structural steel | ASTM A36, min. | 250 (36) | 400 (58) | 200 | 20–23 |
| A992 structural steel (W-shapes) | ASTM A992, min. | 345 (50) | 450 (65) | 200 | 18–21 |
| Grade 60 rebar | ASTM A615 Gr 60, min. | 414 (60) | 621 (90) | 200 | 7–9 |
| 1018 carbon steel, cold drawn | AISI 1018, typical | 370 (54) | 440 (64) | 205 | 15 |
| 4140 alloy steel, annealed | AISI 4140, typical | 415 (60) | 655 (95) | 205 | 26 |
| 304 stainless steel, annealed | ASTM A240, min. | 205 (30) | 515 (75) | 193 | 40 |
| Bolt, property class 8.8 (≤ M16) | ISO 898-1, min. | 640 (93) | 800 (116) | 200 | 12 |
| Bolt, property class 10.9 | ISO 898-1, min. | 940 (136) | 1040 (151) | 200 | 9 |
| Bolt, SAE Grade 5 (¼–1 in) | SAE J429, min. | 634 (92) | 827 (120) | 200 | 14 |
| Bolt, SAE Grade 8 | SAE J429, min. | 896 (130) | 1034 (150) | 200 | 12 |
| Aluminum 6061-T6 | Typical | 276 (40) | 310 (45) | 68.9 | 12 |
| Aluminum 7075-T6 | Typical | 503 (73) | 572 (83) | 71.7 | 11 |
| Titanium Ti-6Al-4V (Grade 5), annealed | Typical | 880 (128) | 950 (138) | 113.8 | 14 |
| Copper C11000, annealed | Typical | 69 (10.0) | 220 (32) | 115 | 45 |
| Gray cast iron, class 30 | ASTM A48, min. | — | 207 (30) | 100 | < 1 |
| Nylon 6/6, dry | Typical | — | 80 (11.6) | 3 | 50+ |
Rebar and bolt areas
| Size | Area (mm²) | Area (in²) | Group |
|---|---|---|---|
| #3 rebar (3/8 in) | 71.0 | 0.11 | ASTM rebar |
| #4 rebar (1/2 in) | 129 | 0.2 | ASTM rebar |
| #5 rebar (5/8 in) | 200 | 0.31 | ASTM rebar |
| #6 rebar (3/4 in) | 284 | 0.44 | ASTM rebar |
| #7 rebar (7/8 in) | 387 | 0.6 | ASTM rebar |
| #8 rebar (1 in) | 510 | 0.79 | ASTM rebar |
| #9 rebar | 645 | 1 | ASTM rebar |
| #10 rebar | 819 | 1.27 | ASTM rebar |
| #11 rebar | 1,006 | 1.56 | ASTM rebar |
| M6 bolt | 20.1 | 0.0312 | Metric bolts (stress area) |
| M8 bolt | 36.6 | 0.0567 | Metric bolts (stress area) |
| M10 bolt | 58.0 | 0.0899 | Metric bolts (stress area) |
| M12 bolt | 84.3 | 0.1307 | Metric bolts (stress area) |
| M16 bolt | 157 | 0.2434 | Metric bolts (stress area) |
| M20 bolt | 245 | 0.3798 | Metric bolts (stress area) |
| M24 bolt | 353 | 0.5472 | Metric bolts (stress area) |
| 1/4-20 bolt | 20.5 | 0.0318 | UNC bolts (stress area) |
| 5/16-18 bolt | 33.8 | 0.0524 | UNC bolts (stress area) |
| 3/8-16 bolt | 50.0 | 0.0775 | UNC bolts (stress area) |
| 1/2-13 bolt | 91.5 | 0.1419 | UNC bolts (stress area) |
| 5/8-11 bolt | 146 | 0.226 | UNC bolts (stress area) |
| 3/4-10 bolt | 215 | 0.334 | UNC bolts (stress area) |
| 1-8 bolt | 391 | 0.606 | UNC bolts (stress area) |
Rebar: ASTM A615 nominal areas. Bolts: tensile stress area As (ISO 898-1 coarse thread; ASME B1.1 UNC), which is smaller than the shank area. 1 ksi = 6.895 MPa; 1 in² = 645.16 mm².
Quick answer
Tensile stress σ = F ÷ A. A 10 mm round bar has A = π × 5² = 78.54 mm², so a 20 kN pull gives 20,000 N ÷ 78.54 mm² = 254.6 MPa (36.9 ksi), just above the 250 MPa yield of A36 steel. Tensile strength (UTS) is the highest stress before it breaks, so breaking load = UTS × A: with A36's 400 MPa minimum UTS that bar breaks at about 31.4 kN. Design to the yield strength with a safety factor.
Examples
| Part | Area | Yield load | Breaking load |
|---|---|---|---|
| 10 mm A36 steel rod | 78.54 mm² | 19.6 kN (250 MPa) | 31.4 kN (400 MPa) |
| #5 Grade 60 rebar | 0.31 in² | 18.6 kip (60 ksi) | 27.9 kip (90 ksi) |
| M12 class 8.8 bolt | 84.3 mm² | 54.0 kN (640 MPa) | 67.4 kN (800 MPa) |
| 1/2-13 SAE Grade 5 bolt | 0.1419 in² | 13.1 kip (92 ksi) | 17.0 kip (120 ksi) |
| 6061-T6 aluminum, 20 × 5 mm bar | 100 mm² | 27.6 kN (276 MPa) | 31.0 kN (310 MPa) |
Enter the force and the section, pick a material, and see stress, safety factor and the yield and breaking loads.
Summary
Tensile stress is the pulling force divided by the cross-sectional area, σ = F/A. Whether a part holds depends on how that stress compares with the material: the yield strength, where permanent stretching starts, and the ultimate tensile strength (UTS), the peak stress before fracture. This calculator takes the force and the section (direct area, round bar, rectangle, ASTM rebar size or a bolt tensile stress area), gives the stress in MPa, Pa, psi and ksi, and with a material picked shows the utilization, safety factor to yield and to UTS, and the load at yield and at break. Add the gauge length and elongation from a test to get strain, elongation % and Young's modulus. Material values are typical or specification minimums from ASTM, SAE and ISO standards and handbooks; use the certified values for design.
How it works
- Pick SI (N, mm) or Imperial (lbf, in) units.
- Enter the tensile force.
- Enter the area directly, or a round bar diameter, a rectangle width × thickness, or choose a rebar or bolt size to fill in its area.
- Optionally pick a material to compare the stress with its yield strength and ultimate tensile strength.
- Optionally enter the gauge length and measured elongation to get strain, elongation % and Young's modulus.
- Click Calculate to see stress, safety factors, the load at yield and at break, and the strain results.
Use cases
- Checking whether a rod, bar, wire or bolt will yield or break under a given pull.
- Finding the breaking load of a steel rod or rebar from its diameter and grade.
- Comparing bolt grades (class 8.8, 10.9, SAE Grade 5, Grade 8) for the same load.
- Turning tensile test load and extension data into stress, strain and modulus.
- Mechanics of materials homework on σ = F/A, ε = ΔL/L₀ and E = σ/ε.
- Estimating the safety factor of a hanger, tie rod or eye bolt.