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Bandsaw Blade Measurement Guide

This Bandsaw Blade Measurement & Conversion Guide brings together the most commonly used blade measurements, thickness conversions, width charts and TPI references in one place. Whether you’re selecting a new bandsaw blade, measuring an existing blade or converting between imperial and metric sizes, you’ll find practical workshop reference information used every day in New Zealand.

You’ll find quick conversions for inches to millimetres, blade thicknesses (thou), blade widths, common NZ blade sizes, sawmill tooth pitch, downloadable conversion charts and our interactive blade TPI calculators for both metal and wood cutting.

These charts are used every day in our Auckland workshop when manufacturing custom bandsaw blades for customers throughout New Zealand and provide a practical reference for engineers, fabricators, sawmills, maintenance staff and home workshops.

In engineering workshops, blade thickness is commonly expressed in thou (thousandths of an inch). If you’re unfamiliar with the term, see this explanation of thousandths of an inch (thou).

Quick Bandsaw Blade Workshop Reference

Common Blade Thicknesses

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Common name Inches mm
14 thou0.014″0.36
20 thou0.020″0.50
22 thou0.022″0.56
25 thou0.025″0.65
35 thou0.035″0.90
42 thou0.042″1.07
50 thou0.050″1.27
63 thou0.063″1.60

Common Blade Widths

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Imperial Decimal mm Common NZ size
1/8″0.125″3.183 mm
1/4″0.250″6.356 mm
3/8″0.375″9.5310 mm
1/2″0.500″12.7013 mm
5/8″0.625″15.8816 mm
3/4″0.750″19.0519 mm
1″1.000″25.4027 mm bi-metal
1 1/4″1.250″31.7534 mm bi-metal
1 1/2″1.500″38.1041 mm bi-metal
2″2.000″50.8054 mm bi-metal
2 1/2″2.500″63.5067 mm bi-metal

Coarse Sawmill Tooth Pitch

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Pitch Calculation TPI
3/4″1 ÷ 0.7501.33
7/8″1 ÷ 0.8751.14
1″1 ÷ 1.0001.00

In real sawmill use these are often rounded. For example, 3/4″ pitch is commonly sold as about 1.3 TPI, and 7/8″ pitch is often sold as about 1.1 TPI.

For those into Math’s 1 inch = 25.4mm so 0.020 ( twenty thou) = 0.02 x 25.4 = 0.5mm and conversely .63mm = 0.63/25.4 = 0.0248″ ( or 25 thou)

Thousands (Thou) to Millimetres Conversion Chart

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Inchesmm Inchesmm Inchesmm Inchesmm Inchesmm
.00050.0127.0060.1524.0160.4064.0350.8890.1002.5400
.00100.0254.0070.1778.0180.4572.0401.0160.1253.1750
.00150.0381.0080.2032.0200.5080.0451.1430.2506.3500
.00200.0508.0090.2286.0220.5588.0501.2700.50012.7000
.00250.0635.0100.2540.0240.6096.0601.5240.75019.0500
.00300.0762.0110.2794.0250.6350.06251.58751.0025.4000
.00350.0889.0120.3048.0260.6604.0701.77801.2531.7500
.00400.1016.0130.3302.0280.7112.0751.90501.5038.1000
.00450.1143.0140.3556.0300.7620.0802.03201.7544.4500
.00500.1270.0150.3810.0320.8128.0902.28602.0050.8000

↔ Swipe left or right to view the full table.

mmInches mmInches mmInches mmInches mmInches
0.0100.000390.0900.003540.2500.009840.9500.037408.0000.31496
0.0150.000590.0950.003740.2600.010241.0000.039379.0000.35433
0.0200.000790.1000.003940.2800.011021.1000.0433110.0000.39370
0.0250.000980.1050.004130.3000.011811.2000.0472411.0000.43307
0.0300.001180.1100.004330.3500.013781.2500.0492112.0000.47244
0.0350.001380.1150.004530.4000.015751.5000.0590613.0000.51181
0.0400.001570.1200.004720.4500.017722.0000.0787414.0000.55118
0.0450.001770.1250.004920.5000.019692.5000.0984315.0000.59055
0.0500.001970.1300.005120.5500.021653.0000.1181116.0000.62992
0.0550.002170.1400.005510.6000.023623.5000.1378017.0000.66929
0.0600.002360.1500.005910.6500.025594.0000.1574818.0000.70866
0.0650.002560.1600.006300.7000.027564.5000.1771719.0000.74803
0.0700.002760.1800.007090.7500.029535.0000.1968520.0000.78740
0.0750.002950.2000.007870.8000.031505.5000.2165421.0000.82677
0.0800.003150.2200.008660.8500.033466.0000.2362222.0000.86614
0.0850.003350.2400.009450.9000.035437.0000.2755925.4001.00000

Prefer a printable version?

Download the complete PDF conversion chart

Bandsaw Blade TPI Calculators

Metal Cutting Bandsaw Blade TPI Calculator

United Products / NZ Bandsaw Blade TPI Calculator

Use this calculator to find an approximate starting point for selecting the correct bandsaw blade tooth pitch. Choose the material type, enter the relevant size, and the recommendation will update automatically.

Recommended blade tooth pitch
Enter a measurement

The calculator will recommend an approximate starting TPI once a valid size is entered.

This calculator provides an approximate starting point only. Final blade selection can depend on material grade, machine condition, work holding, cutting speed, coolant, bundle cutting and operator preference.

Wood Bandsaw Blade TPI & Radius Calculator

Wood Bandsaw Blade TPI & Radius Calculator

Use this calculator to choose a practical wood bandsaw blade tooth pitch and, for curved work, the maximum blade width for the radius you need to cut.

Recommended wood bandsaw blade
Enter thickness

The calculator will recommend a starting TPI. Choose radius cutting if you also need a blade width recommendation.

This calculator provides an approximate starting point only. Final blade selection can depend on timber species, green or dry timber, blade condition, machine condition, feed pressure, guide setup and the quality of finish required.

A thou is one thousandth of an inch (0.001″). It is commonly used to describe bandsaw blade thickness in engineering and manufacturing. For example, a 20 thou blade is approximately 0.50 mm thick, while a 42 thou blade is approximately 1.07 mm thick.

One inch equals 25.4 millimetres. This exact conversion is used worldwide for engineering, machining and bandsaw blade measurements. The conversion charts on this page provide quick references for both inch-to-millimetre and millimetre-to-inch conversions.

Bandsaw blade width is measured from the tip of the tooth to the back edge of the blade. It does not include any tooth set. Blade width affects cutting capacity, stability and the minimum radius that can be cut on woodworking bandsaws.

The correct teeth per inch (TPI) depends on the material being cut and its thickness. A good starting point is to keep at least three teeth engaged in the material during the cut. This page includes interactive TPI calculators for both metal-cutting and wood-cutting bandsaw blades to help select an appropriate starting point.

Bandsaw blade terminology
image of a straight 3 and 4 tpi blade plus a variable 3/4 blade

About the Author

Allan Breckell

Managing Director
United Products / NZ Bandsaw

Author of United Products’ technical guides and blade calculators

Allan writes the technical guides published on this website and works directly with customers throughout New Zealand, helping them select, troubleshoot and optimise industrial bandsaw blade applications.

© United Products NZ – unitedproducts.co.nz