Fastener
Bolt Length Calculator
Correct bolt length for a stack of parts, washers and a nut, rounded to a standard length.
length = parts + washers + nut height + p…
Also called screw length calculator · how long a bolt do i need
Engineering · 8 calculators
Fastener Calculators
Bolt length, bolt torque, thread pitch and engagement, screw gauges, nut and wrench sizes, fastener loads and bolt patterns.
Fastener
Bolt Torque Calculator
Tightening torque for a bolt from its size, grade and friction condition, with the clamp load.
T = K × D × F (K is the nut factor, F the…
Also called torque spec calculator · bolt tightening torque
Fastener
Thread Pitch Calculator
Convert between thread pitch and threads per inch, with the standard metric coarse pitch.
pitch (mm) = 25.4 ÷ threads per inch
Also called tpi to pitch · threads per inch
Fastener
Thread Engagement Calculator
Minimum thread engagement depth so the threads are stronger than the bolt itself.
Le = (A_s × bolt strength) / (shear stren…
Also called minimum thread engagement · tapped hole depth
Fastener
Screw Size Calculator
Metric and imperial screw dimensions — major, minor and pitch diameters plus clearance holes.
minor diameter = D − 1.0825 × pitch
Also called screw dimensions · metric screw chart
Fastener
Nut Size Calculator
Spanner size, height and washer dimensions for standard metric nuts.
Across corners = across flats × 2/√3
Also called spanner size · wrench size for bolt
Fastener
Fastener Load Calculator
Tensile and shear capacity of a bolt, and the load shared across a group of fasteners.
tensile capacity = stress area × tensile …
Also called bolt strength calculator · bolt shear capacity
Fastener
Bolt Pattern Calculator
Bolt circle diameter, hole spacing and X-Y coordinates for a circular bolt pattern.
chord = 2R·sin(180°/n)
Also called bolt circle calculator · pcd calculator
Key fastener formulas
| Bolt Length | length = parts + washers + nut height + protrusion |
|---|---|
| Bolt Torque | T = K × D × F (K is the nut factor, F the clamp load) |
| Thread Pitch | pitch (mm) = 25.4 ÷ threads per inch |
| Thread Engagement | Le = (A_s × bolt strength) / (shear strength × π × D × 0.75) |
| Screw Size | minor diameter = D − 1.0825 × pitch |
| Nut Size | Across corners = across flats × 2/√3 |
| Fastener Load | tensile capacity = stress area × tensile strength · shear ≈ 0.6 × tensile |
| Bolt Pattern | chord = 2R·sin(180°/n) |