Rivet Size and Length Calculator
Calculate the correct rivet diameter and length for your joint.
Covers solid, blind, and structural rivets.
How rivet sizing works:
A rivet must be wide enough to carry the shear load and long enough to form a proper shop head (the deformed end) after installation. Too short and the shop head is thin and weak. Too long and the excess material buckles or mushrooms unevenly.
Rivet diameter rule: The rivet diameter should be approximately 1.5 to 3 times the thickness of the thickest sheet being joined. For structural work, the standard is:
Rivet diameter ≈ 3 × Thinnest sheet thickness (minimum)
In practice, common rivet diameters are standardized: 2.4 mm (3/32 in), 3.2 mm (1/8 in), 4.0 mm (5/32 in), 4.8 mm (3/16 in), 6.4 mm (1/4 in).
Rivet length formula: The rivet must extend beyond the total grip (combined thickness of all sheets) by enough to form the shop head.
For solid rivets: Rivet length = Total grip + 1.5 × Rivet diameter
For blind (pop) rivets: Rivet length = Total grip + Mandrel head height (typically 1.5–3 mm depending on size)
Grip range table for blind rivets (common sizes):
| Rivet Diameter | Min Grip | Max Grip | Drill Hole Size |
|---|---|---|---|
| 2.4 mm (3/32 in) | 0.5 mm | 6.4 mm | 2.5 mm |
| 3.2 mm (1/8 in) | 0.5 mm | 9.5 mm | 3.3 mm |
| 4.0 mm (5/32 in) | 0.5 mm | 12.7 mm | 4.1 mm |
| 4.8 mm (3/16 in) | 0.8 mm | 15.9 mm | 4.9 mm |
| 6.4 mm (1/4 in) | 1.6 mm | 19.0 mm | 6.5 mm |
Rivet material matching: Always match rivet material to the sheets to prevent galvanic corrosion:
- Aluminum sheets → Aluminum rivets (5052 or 5056 alloy)
- Steel sheets → Steel rivets (low carbon or stainless)
- Stainless steel sheets → Stainless steel rivets (same grade)
- Copper sheets → Copper rivets
Shear strength by diameter (aluminum blind rivets):
| Diameter | Shear Strength (per rivet) |
|---|---|
| 2.4 mm | ~110 N (25 lbf) |
| 3.2 mm | ~200 N (45 lbf) |
| 4.0 mm | ~330 N (75 lbf) |
| 4.8 mm | ~490 N (110 lbf) |
| 6.4 mm | ~890 N (200 lbf) |
Worked example: Joining two 1.5 mm aluminum sheets with blind rivets:
- Total grip: 1.5 + 1.5 = 3.0 mm
- Diameter: 3 × 1.5 = 4.5 mm → use 4.8 mm (3/16 in) standard
- Length: 3.0 + 2.5 mm (mandrel head) = 5.5 mm → choose 6.4 mm (next standard length)
- Drill size: 4.9 mm
- Shear strength: ~490 N per rivet
Rivet spacing rules:
- Edge distance: minimum 2× rivet diameter from edge
- Pitch (center-to-center): minimum 3× rivet diameter
- Row spacing: minimum 2.5× rivet diameter between rows
Hole preparation: The drill hole should be 0.1–0.2 mm larger than the rivet body for blind rivets, and 0.1 mm larger (tight fit) for solid rivets. Deburr holes on both sides before inserting the rivet.