Rivet Size
Determine the right rivet shank diameter, shank length, and hole size for button head and countersunk rivets based on plate thickness. Free online rivet sizing tool.
About This Calculator
About the Rivet Size Calculator
This rivet size calculator helps engineers, fabricators, metalworkers, and DIY enthusiasts determine the correct rivet dimensions for their fastening projects. By entering the thickest plate thickness and total clamping thickness, plus selecting the rivet head shape and application type, the calculator computes the minimum shank diameter, recommends the nearest standard rivet size, calculates the allowance for forming the closing head, and provides the total rivet shank length needed. It also shows the recommended hole diameter range for drilling.
The calculations follow standard rivet sizing formulas: the minimum shank diameter equals 3 times the thickest plate thickness (Dmin = tmax x 3). The shank length allowance depends on the head shape and application — 1.5 times the rivet diameter for button heads in general construction, 1.7 for pressurized boiler construction, and 0.5 for countersunk heads. The total shank length is the sum of the total plate thickness and this allowance. The hole diameter should match the rivet shank size with a maximum clearance of 0.15 mm (0.006 inch).
Regional Notes
US: Standard rivet sizes follow fractional inch increments (1/16 to 1-5/8 inches). The 0.006 inch clearance rule for hole diameters is standard practice. Common applications include aircraft assembly, metal building construction, and heavy equipment manufacturing.
UK: Metric rivet sizes (1.6 mm to 40 mm) are standard per BS 4620. Button head rivets are common in structural steelwork and shipbuilding. Pressurized boiler applications follow BS 5045 standards for rivet sizing.
India: IS 1929 specifies metric rivet dimensions for general engineering purposes. Common applications include structural steel fabrication, bridge construction, and railway carriage assembly. Button head rivets are most common in construction and heavy engineering.
Frequently Asked Questions
How do you calculate rivet size?
Calculate the minimum shank diameter by multiplying the thickest plate thickness by 3. Then choose the next larger standard rivet size from standard diameter tables. The shank length is the total clamping thickness plus an allowance of 1.5 times the rivet diameter for general button head applications, 1.7 for boiler construction, or 0.5 for countersunk heads.
What is the formula for rivet diameter?
The formula for minimum rivet shank diameter is Dmin = tmax x 3, where tmax is the thickness of the thickest plate being fastened. For example, if the thickest plate is 2 mm, the minimum rivet diameter is 6 mm, and you would select the next standard size above 6 mm, such as 6.35 mm (1/4 inch).
How do you determine rivet shank length?
The rivet shank length L is calculated as L = S + A, where S is the total clamping thickness of all plates and A is the allowance for forming the closing head. For button head rivets in general construction with diameter up to 20 mm, A = D x 1.5. For boiler construction up to 20 mm, A = D x 1.7. For countersunk heads, A = D x 0.5 for any diameter.
What is the grip range of a rivet?
The grip range is the range of material thicknesses a rivet can securely fasten. It is approximately the rivet shank length minus 1.5 times the rivet diameter. For example, a 3.2 x 12 mm rivet (1/8 x 1/2 inch) has a grip range of about 7.9 mm. Always select rivets whose grip range closely matches your total material thickness.
What size hole do you drill for a rivet?
Drill the hole to the same nominal diameter as the rivet shank with up to 0.15 mm (0.006 inch) additional clearance. The minimum hole diameter equals the rivet shank diameter, and the maximum hole diameter is the shank diameter plus 0.15 mm. For example, a 4.76 mm (3/16 inch) rivet needs a hole between 4.76 mm and 4.91 mm.
Can a rivet be too long?
Yes, using a rivet that is too long can prevent proper tightening and may cause the rivet to buckle rather than form a secure closing head. Choose a rivet with a shank length as close as possible to your calculated length. Many rivet suppliers specify a grip range that indicates the range of material thicknesses each rivet size can accommodate.
What is the difference between button head and countersunk rivets?
Button head rivets leave a rounded dome visible above the material surface and are used in general construction and boiler applications. Countersunk rivets sit flush with the material surface for a smooth finish and are used in lightweight applications where a flat surface is required. Countersunk rivets require only half the shank allowance (0.5 x D) compared to button heads.
What are standard rivet sizes available?
Standard rivet shank diameters range from 1/16 inch (1.59 mm) to 1-5/8 inch (41.28 mm) in fractional inch increments. Common sizes include 1/8, 3/16, 1/4, 5/16, 3/8, 1/2, 5/8, 3/4, 7/8, and 1 inch. Metric equivalents range from 1.6 mm to 40 mm. Always select the next standard size larger than your calculated minimum diameter.