Thread Finder

Search 3,100+ sizes across 73 thread standards: metric, UNC/UNF, BSP, NPT, trapezoidal and more. Pitch, TPI, tap drill and diameter in one place.

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Converters

TPI ↔ Pitch

TPI Pitch (mm)

Pitch (mm) = 25.4 ÷ TPI

Inch ↔ Millimetre

Inch mm

Fractions work too, e.g. 3/8 or 1 1/4

Metric Tap Drill

Diameter (mm) Pitch (mm)

Tap drill ≈ D − P

Browse

All Thread Standards

Every standard has its own page with the full table and a live filter.

ISO Metric

ISO metric threads have a 60° symmetric profile and are designated by M, the nominal diameter and, for fine threads, the pitch (e.g. M10 × 1).

Unified Inch (UNC / UNF / UN)

Unified inch threads share the 60° profile with ISO metric but are sized in inches and specified by threads per inch (TPI), e.g. 1/4"-20 UNC.

UNC Unified Coarse Thread ANSI/ASME B1.1 33 rows · #1 - 64 UNC – 4" - 4 UNC UNF Unified Fine Thread ANSI/ASME B1.1 24 rows · #0 - 80 UNF – 1 1/2" - 12 UNF UNEF Unified Extra-Fine Thread ANSI/ASME B1.1 24 rows · N 12 - 32 UNEF – 1 11/16" - 18 UNEF 12-UN Constant Pitch Series ANSI/ASME B1.1 49 rows · 5/8" - 12-UN – 6" - 12-UN 16-UN Constant Pitch Series ANSI/ASME B1.1 54 rows · 7/16" - 16-UN – 6" - 16-UN 20-UN Constant Pitch Series ANSI/ASME B1.1 29 rows · 5/16" - 20-UN – 3" - 20-UN 8-UN Constant Pitch Series ANSI/ASME B1.1 32 rows · 1 1/16" - 8-UN – 4" - 8-UN UNR Unified Thread (Rounded Root) ASME B1.1 237 rows · 5/16" - 20 UNR – 6" - 16 UNR UNS Unified Special Thread ASME B1.1 115 rows · 10 - 28 UNS – 6" - 14 UNS UNM Unified Miniature Thread ANSI/ASME B1.10 14 rows · 0.30 UNM – 1.40 UNM

Pipe Threads (BSP / NPT)

Pipe threads seal or connect pipework. Tapered forms (NPT, BSPT/R) seal on the thread itself; parallel forms (BSPP/G, NPS) seal with a gasket or O-ring.

BSPP Parallel Pipe Thread (G) ISO 228-1 / DIN 259 27 rows · G 1/16" – G 6" NPT American Taper Pipe Thread ANSI/ASME B1.20.1 19 rows · 1/16" - 27 NPT – 12" - 8 NPT BSPT Tapered Pipe Thread (R / Rp / Rc) ISO 7-1 / EN 10226 15 rows · R 1/16" – R 6" NPTF Dryseal Taper Pipe Thread ANSI B1.20.3 12 rows · 1/16" - 27 NPTF – 4" - 8 NPTF NPSM Straight Pipe Thread (Mechanical) ANSI B1.20.1 15 rows · 1/8" - 27 NPSM – 6" - 8 NPSM Metric Taper Thread DIN 158 36 rows · M 5 keg – M 60 x 2 keg NPSC Straight Pipe Thread (Couplings) ANSI B1.20.1 13 rows · 1/8" - 27 NPSC – 4" - 8 NPSC NPSF Dryseal Straight Pipe Thread ANSI B1.20.3 7 rows · 1/16" - 27 NPSF – 1" - 11 1/2 NPSF NPSL Straight Pipe Thread (Locknuts) ANSI B1.20.1 18 rows · 1/8" - 27 NPSL – 12" - 8 NPSL

Whitworth & British

British threads based on Whitworth's 55° profile with rounded crests and roots, still found on older machinery, pipe fittings and model engineering.

BSW British Standard Whitworth BS 84 32 rows · W 1/16" – W 4" BSF British Standard Fine BS 84 30 rows · BSF 3/16" – BSF 4 1/4" BA British Association Thread BS 93 26 rows · BA No. 0 – BA No. 25 BSB British Standard Brass BS 84 11 rows · BSB 1/8" – BSB 1 1/2" ME Model Engineer Thread 16 rows · ME 1/8" – ME 1/2" Whitworth Fine Thread 1 DIN 239 91 rows · W 56 x 1/4" – W 499 x 1/4" Whitworth Fine Thread 2 DIN 240 41 rows · W 20 x 1/10" – W 189 x 1/6" Whitworth Instrument Thread 32 rows · 10 – 100 Whitworth Fine Thread, 12 TPI DIN LON 282 14 rows · W 23 x 1/12" – (W 46 x 1/12") Whitworth Fine Thread, 10 TPI DIN LON 286 22 rows · W 20 x 1/10" LON – W 80 x 1/10" LON Whitworth Fine Thread, 6 TPI DIN LON 287 21 rows · W 60 x 1/6" LON – W 154 x 1/6" LON Whitworth Fine Thread, Special DIN 30284 / DIN LON 293 5 rows · W 14 x 1/12" DIN 30284 – W 18 x 1/11" DIN 30284

Trapezoidal, ACME & Buttress

Power and lead-screw threads transmit motion and load. Trapezoidal and ACME threads are symmetric; buttress threads carry heavy load in one direction.

Trapezoidal Thread (Tr), Standard Pitch DIN 103 / ISO 2904 64 rows · Tr 9 x 2 – Tr 300 x 24 Trapezoidal Thread (Tr), Fine Pitch DIN 103 65 rows · Tr 8 x 1,5 – Tr 300 x 12 ACME Thread ASME B1.5 23 rows · 1/4" - 16 ACME – 5" - 2 ACME Buttress Thread (S), Coarse DIN 513 62 rows · S 10 x 2 – S 300 x 24 Buttress Thread (S), Fine DIN 514 77 rows · S 12 x 2 – S 620 x 24 Stub ACME Thread ASME B1.8 23 rows · 1/4" - 16 STUB ACME – 5" - 2 STUB ACME Buttress Thread 45° DIN 2781 45 rows · S 100 x 5 – S 1250 x 40 Plastic Container Threads (KS / KT) DIN 6063 35 rows · KS 10 – KS 60

Knuckle & Round Threads

Rounded (knuckle) profiles tolerate dirt, damage and thin-walled or cast parts, so they are used on couplings, glass, lamp holders and heavy-duty fittings.

Dairy Coupling Thread DIN 11851 13 rows · Rd 28 x 1/8" – Rd 190 x 1/4" Knuckle Thread (Rd), Inch Pitch DIN 405 63 rows · Rd 8 x 1/10" – Rd 200 x 1/4" Edison Screw Thread (E) DIN 40400 8 rows · E 5.5 – E 40 Glass Container Knuckle Thread (GL) DIN 168 24 rows · GL 8 – GL 125 Knuckle Thread (Rd), Metric Pitch DIN 20400 47 rows · Rd 10 – Rd 300 Lighting Fitting Glass Thread DIN 40450 6 rows · Glasg 74.5 – Glasg 188

Special Purpose

Threads defined for one application, such as cable glands, tyre valves, bicycles and sewing machines.

PG Conduit Thread (Panzergewinde) DIN 40430 44 rows · Pg 7 – Pg 48 Bicycle Thread (Fg) DIN 79012 10 rows · Fg 2 – Fg 34.8 Tyre Valve Thread (Vg) DIN 7756 7 rows · Vg 5 – Vg 12 Sewing Machine Thread Nähnorm 100 16 rows · 5/64" – 9/16"

Historical & Obsolete

Threads that have been withdrawn or superseded. Listed for repair, restoration and reverse-engineering of older equipment.

Sellers Thread (US Standard) 27 rows · 1/4" - 20 – 6" - 2 1/4 Sharp V Thread 37 rows · 1/4" – 4" Bodmer Thread 30 rows · 3.000 – 50.000 C.E.I. Cycle Thread 21 rows · 0.056 – 1.500 Ducommun Steinle Thread 29 rows · 3.00 – 80.00 French Metric Thread (SF) 34 rows · 0 – 19 Hamann Collet Thread 14 rows · 1 – 13 Löwenherz Thread 18 rows · 1.000 – 10.000 Siemens & Halske Thread 12 rows · 11 – 36 S. J. Thread 29 rows · 6.0 – 80.0 Thury Thread (Swiss) 26 rows · 0 – 25 VDI Thread 18 rows · 6.00 – 40.00

Conversion & Reference Tables

Conversion and reference tables to use alongside the thread charts.

TPI to Pitch (mm) Conversion 66 rows Inch Fractions to Millimetres 128 rows Number & Letter Drill Sizes ANSI B94.11M 170 rows Thread Designations & Abbreviations 33 rows

Reference values only. Verify against the current edition of the governing standard before use in production drawings. Need a threaded part made? Send us your drawing.