Threads · Free Excel and PDF
NPT Thread Size Chart (ASME B1.20.1)
NPT thread chart for tapered pipe threads used on gauges, transmitters, manifolds and process connections.
Excel (.xlsx)Print ready PDF13 rowsFree, no sign up
Download
- 13 rows of reference data
- Print ready A4 PDF
- How to Use sheet with steps
- Basis and standard stated
- Excel, Google Sheets and LibreOffice
- Free, no sign up, no macros
NPT sizes
| NPT size | TPI | Pitch mm | OD inch | OD mm |
|---|---|---|---|---|
| 1/16 | 27 | 0.941 | 0.312 | 7.94 |
| 1/8 | 27 | 0.941 | 0.405 | 10.29 |
| 1/4 | 18 | 1.411 | 0.540 | 13.72 |
| 3/8 | 18 | 1.411 | 0.675 | 17.14 |
| 1/2 | 14 | 1.814 | 0.840 | 21.34 |
| 3/4 | 14 | 1.814 | 1.050 | 26.67 |
| 1 | 11.5 | 2.209 | 1.315 | 33.40 |
| 1 1/4 | 11.5 | 2.209 | 1.660 | 42.16 |
| 1 1/2 | 11.5 | 2.209 | 1.900 | 48.26 |
| 2 | 11.5 | 2.209 | 2.375 | 60.32 |
| 2 1/2 | 8 | 3.175 | 2.875 | 73.02 |
| 3 | 8 | 3.175 | 3.500 | 88.90 |
| 4 | 8 | 3.175 | 4.500 | 114.30 |
Advertisement
About this Table
NPT thread chart for tapered pipe threads used on gauges, transmitters, manifolds and process connections.
Basis: ASME B1.20.1 Pipe Threads, General Purpose (Inch). Taper 1 in 16 on diameter; 60° thread angle.
How to use
- Measure the outside diameter of a male thread and count threads per inch.
- Match both to the table.
- 1/2 NPT is the usual transmitter and gauge connection.
Notes
- NPT and BSPT look similar; BSP has a 55° angle and different TPI for most sizes.
- NPT seals on the thread with tape or sealant; NPTF is the dry seal version.
Related tools
Advertisement
Frequently Asked Questions
What is the OD of 1/2 NPT?
0.840 inch (21.34 mm), 14 threads per inch.
Can I connect NPT to BSPT?
Not reliably. Only 1/2 and 3/4 share the same TPI and they still leak.
What size is 1/4 NPT?
0.540 inch OD (13.72 mm), 18 TPI.
You May Also Like
Learn more on the blog
Pressure transmitter installation tips
A practical guide on instrumentationblog.in that explains the engineering behind this table.
Read Full ArticleMore Engineering Reference Tables
Type K Thermocouple Table (mV vs °C)Temperature · Excel and PDFType J Thermocouple Table (mV vs °C)Temperature · Excel and PDFType T Thermocouple Table (mV vs °C)Temperature · Excel and PDFType E Thermocouple Table (mV vs °C)Temperature · Excel and PDFType N Thermocouple Table (mV vs °C)Temperature · Excel and PDFType R Thermocouple Table (mV vs °C)Temperature · Excel and PDFType S Thermocouple Table (mV vs °C)Temperature · Excel and PDFType B Thermocouple Table (mV vs °C)Temperature · Excel and PDFPt100 RTD Table (Ω vs °C)Temperature · Excel and PDFPt1000 RTD Table (Ω vs °C)Temperature · Excel and PDFThermocouple Tolerance Class Table (IEC 60584)Temperature · Excel and PDFRTD Tolerance Class Table (IEC 60751)Temperature · Excel and PDFCarbon Steel Pipe Schedule Chart (ASME B36.10M)Piping · Excel and PDFStainless Steel Pipe Schedule Chart (ASME B36.19M)Piping · Excel and PDFSteel Pipe Weight Chart (kg per metre)Piping · Excel and PDFPipe Inside Diameter and Flow Area ChartPiping · Excel and PDFNPS to DN Pipe Size ChartPiping · Excel and PDFFlange Pressure Temperature Rating Table (ASME B16.5)Piping · Excel and PDFSaturated Steam Table by TemperatureSteam and Water · Excel and PDFSaturated Steam Table by PressureSteam and Water · Excel and PDFSuperheated Steam TableSteam and Water · Excel and PDFWater Density and Viscosity TableSteam and Water · Excel and PDFWater Boiling Point vs Altitude TableSteam and Water · Excel and PDFAWG Wire Size Chart (AWG to mm²)Electrical · Excel and PDFMetric Cable Size and Resistance Table (IEC 60228)Electrical · Excel and PDFIP Rating Chart (IEC 60529)Electrical · Excel and PDFNEMA Enclosure Types Chart (NEMA 250)Electrical · Excel and PDFNEMA to IP Conversion ChartElectrical · Excel and PDFMotor Full Load Current Table (3 Phase)Electrical · Excel and PDFElectrical Wire Colour Code ChartElectrical · Excel and PDF4 to 20 mA Conversion TableInstrumentation · Excel and PDFSquare Root Flow and DP TableInstrumentation · Excel and PDFISA Instrument Letter Codes Table (ISA 5.1)Instrumentation · Excel and PDFHazardous Area Zone and Gas Group TableInstrumentation · Excel and PDFHazardous Area Temperature Class Table (T1 to T6)Instrumentation · Excel and PDFSIL Level PFD and RRF Table (IEC 61508)Instrumentation · Excel and PDFCv to Kv Conversion TableInstrumentation · Excel and PDFBSP Thread Size Chart (ISO 228 and ISO 7)Threads · Excel and PDFMetric Thread Pitch Chart (ISO 261)Threads · Excel and PDF