Engineering Tool
Metric Thread Profile Calculator
Determine precise metric thread dimensions by inputting thread size, pitch, and tolerances. Ensure components fit correctly, comply with standards, and meet design and manufacturing requirements.
ISO 965-1:1998
ISO 68-1:1998
ASME B1.13M-2005
⚙ Calculate Your Metric Thread Profile
Thread Dimension Calculator
Coarse pitch pre-filled on size select
⚠ Please select a nominal diameter and pitch before calculating.
Thread Profile Results
External Thread (Bolt / Screw)
Major diameter
d
—
Pitch diameter
d₂
—
Minor diameter
d₃
—
Thread height (ext)
h₃
—
Internal Thread (Nut)
Major diameter
D
—
Pitch diameter
D₂
—
Minor diameter
D₁
—
Thread height (int)
H₁
—
Common Thread Geometry
Pitch
P
—
Full triangle height
H
—
Root radius (min)
r
—
Lead angle
ψ
—
Tolerance Zone
Tolerance class
—
Pitch diameter tol.
Td₂/TD₂
—
Major/Minor diam. tol.
Td/TD₁
—
Fundamental deviation
es/EI
—
📐 Thread Notation Model (ISO 68-1)
Symbol Reference
Internal Thread (Nut)
DBasic major diameter of internal thread
D₂Basic pitch diameter of internal thread
D₁Basic minor diameter of internal thread
H₁Depth of internal thread = 5H/8
External Thread (Bolt)
dBasic major diameter of external thread
d₂Basic pitch diameter of external thread
d₃Minor diameter of external thread
h₃Depth of external thread = 17H/24
General
PPitch — axial distance between threads
HHeight of fundamental triangle = P × √3/2
rRoot radius (min) = P/8 × √3 × 2/3
ψLead angle at pitch diameter
Key Formulas
d₂= d − 0.6495 × P
d₃= d − 1.2269 × P
D₁= D − 1.0825 × P
D₂= D − 0.6495 × P
Standards basis: Calculations follow ISO 965-1:1998 (general dimensions and tolerances), ISO 68-1:1998 (thread form specifications), and ASME B1.13M-2005 (metric threads per U.S. standards). Values are for guidance — always verify against current published standards for critical applications.