Timing Belt Pitch Chart & Size Reference
Timing Belt Pitch Chart & Size Reference
This page is a single-source reference for every standard industrial timing belt pitch, covering all major profile families: imperial trapezoidal (MXL through XXH), metric trapezoidal (T-series and AT-series), HTD curvilinear (3M through 20M), and GT curvilinear (GT2 and GT3). Use this chart to identify a belt by its pitch, compare profiles at similar pitches, and find the correct part number format for ordering.
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Master Pitch Chart: All Profiles
This table lists every standard industrial timing belt profile sorted by pitch from smallest to largest. Use it to identify your belt profile or compare profiles at similar pitches.
| Profile | Pitch | Metric Equiv. | Tooth Shape | Family | Tooth Height | Standard Widths |
|---|---|---|---|---|---|---|
| MXL | 0.080" | 2.032 mm | Trapezoidal | Imperial Trapezoidal | 0.020" | 1/8" to 1/4" |
| GT2 2mm | 0.079" | 2 mm | Curvilinear | GT | 0.75 mm | 6 mm, 9 mm |
| T2.5 | 0.098" | 2.5 mm | Trapezoidal | Metric Trapezoidal | 0.7 mm | 4 mm to 10 mm |
| 3M | 0.118" | 3 mm | Curvilinear | HTD | 1.2 mm | 6 mm to 15 mm |
| T5 | 0.197" | 5 mm | Trapezoidal | Metric Trapezoidal | 1.2 mm | 10 mm to 25 mm |
| 5M | 0.197" | 5 mm | Curvilinear | HTD | 2.1 mm | 9 mm to 25 mm |
| AT5 | 0.197" | 5 mm | Mod. Trapezoidal | AT | 1.2 mm | 10 mm to 32 mm |
| XL | 1/5" (0.200") | 5.08 mm | Trapezoidal | Imperial Trapezoidal | 0.050" | 1/4" to 1" |
| 8M | 0.315" | 8 mm | Curvilinear | HTD | 3.4 mm | 15 mm to 85 mm |
| L | 3/8" (0.375") | 9.525 mm | Trapezoidal | Imperial Trapezoidal | 0.075" | 1/2" to 2" |
| T10 | 0.394" | 10 mm | Trapezoidal | Metric Trapezoidal | 2.5 mm | 16 mm to 50 mm |
| AT10 | 0.394" | 10 mm | Mod. Trapezoidal | AT | 2.5 mm | 16 mm to 50 mm |
| H | 1/2" (0.500") | 12.7 mm | Trapezoidal | Imperial Trapezoidal | 0.100" | 3/4" to 3" |
| 14M | 0.551" | 14 mm | Curvilinear | HTD | 6.0 mm | 40 mm to 170 mm |
| AT20 | 0.787" | 20 mm | Mod. Trapezoidal | AT | 5.0 mm | 25 mm to 100 mm |
| 20M | 0.787" | 20 mm | Curvilinear | HTD | 8.4 mm | 50 mm to 230 mm |
| XH | 7/8" (0.875") | 22.225 mm | Trapezoidal | Imperial Trapezoidal | 0.200" | 2" to 4" |
| XXH | 1-1/4" (1.250") | 31.75 mm | Trapezoidal | Imperial Trapezoidal | 0.275" | 2" to 5" |
Imperial Trapezoidal Profiles (MXL, XL, L, H, XH, XXH)
The imperial trapezoidal family uses inch-based pitch measurements and straight-sided teeth. This is the original timing belt profile family and remains the most common in North American industrial equipment. Pitch values progress from miniature (MXL) to maximum torque (XXH).
| Profile | Pitch (inches) | Pitch (mm) | Tooth Height | Min. Pulley Teeth | Load Class |
|---|---|---|---|---|---|
| MXL | 0.080" | 2.032 | 0.020" (0.51 mm) | 10 | Miniature |
| XL | 0.200" (1/5") | 5.080 | 0.050" (1.27 mm) | 10 | Light |
| L | 0.375" (3/8") | 9.525 | 0.075" (1.91 mm) | 10 | Medium |
| H | 0.500" (1/2") | 12.700 | 0.100" (2.54 mm) | 14 | Heavy |
| XH | 0.875" (7/8") | 22.225 | 0.200" (5.08 mm) | 18 | Extra Heavy |
| XXH | 1.250" (1-1/4") | 31.750 | 0.275" (6.99 mm) | 18 | Maximum |
Metric Trapezoidal Profiles (T-Series & AT-Series)
Metric trapezoidal belts use millimeter-based pitch and are standard on European-designed equipment. The AT (Advanced Tooth) variants feature a modified tooth form with improved load distribution over the standard T-series.
| Profile | Pitch (mm) | Type | Tooth Height | Min. Pulley Teeth | Load Class |
|---|---|---|---|---|---|
| T2.5 | 2.5 | Standard | 0.7 mm | 12 | Miniature |
| T5 | 5 | Standard | 1.2 mm | 10 | Light-Medium |
| T10 | 10 | Standard | 2.5 mm | 12 | Medium-Heavy |
| T20 | 20 | Standard | 5.0 mm | 12 | Heavy |
| AT5 | 5 | Advanced | 1.2 mm | 10 | Medium |
| AT10 | 10 | Advanced | 2.5 mm | 12 | Heavy |
| AT20 | 20 | Advanced | 5.0 mm | 12 | Extra Heavy |
HTD Curvilinear Profiles (3M, 5M, 8M, 14M, 20M)
HTD (High Torque Drive) belts use a rounded, curvilinear tooth that distributes stress more evenly than trapezoidal teeth. HTD is the most widely used curvilinear profile family for general industrial applications.
| Profile | Pitch (mm) | Tooth Height | Belt Thickness (approx.) | Min. Pulley Teeth | Load Class |
|---|---|---|---|---|---|
| 3M | 3 | 1.2 mm | 2.4 mm | 10 | Light |
| 5M | 5 | 2.1 mm | 3.8 mm | 14 | Light-Medium |
| 8M | 8 | 3.4 mm | 5.6 mm | 22 | Medium-Heavy |
| 14M | 14 | 6.0 mm | 10.0 mm | 28 | Heavy |
| 20M | 20 | 8.4 mm | 13.2 mm | 34 | Extra Heavy |
For full HTD specifications and inventory, see our HTD Timing Belts collection.
GT / GT2 / GT3 Curvilinear Profiles
GT profiles use an optimized curvilinear tooth that improves on standard HTD with lower backlash and higher load capacity. GT3 (PowerGrip GT3) is the current generation, using HNBR rubber for extended temperature range and service life.
| Profile | Pitch (mm) | Generation | Body Material | Temp. Range | Load vs. HTD |
|---|---|---|---|---|---|
| GT2 2mm | 2 | 2nd gen | Neoprene or PU | -30°F to +185°F | Higher (optimized tooth) |
| GT3 3mm | 3 | 3rd gen | HNBR | -65°F to +250°F | Up to 25% higher |
| GT3 5mm | 5 | 3rd gen | HNBR | -65°F to +250°F | Up to 25% higher |
| GT3 8mm | 8 | 3rd gen | HNBR | -65°F to +250°F | Up to 25% higher |
| GT3 14mm | 14 | 3rd gen | HNBR | -65°F to +250°F | Up to 25% higher |
For full GT specifications, pulley compatibility, and generation comparisons, see our GT / GT2 / GT3 Timing Belts collection.
Part Number Formats by Profile Family
Timing belt part numbers encode pitch length, profile, and width. The format differs by profile family. Use this reference to decode any timing belt part number.
| Family | Format | Example | Decoded |
|---|---|---|---|
| Imperial Trapezoidal (XL) | [Pitch length tenths][Profile][Width hundredths] | 170XL037 | 17.0" pitch length, XL, 3/8" wide |
| Imperial Trapezoidal (L) | [Pitch length tenths][Profile][Width hundredths] | 300L075 | 30.0" pitch length, L, 3/4" wide |
| Imperial Trapezoidal (H) | [Pitch length tenths][Profile][Width hundredths] | 700H200 | 70.0" pitch length, H, 2" wide |
| HTD (5M, 8M, 14M) | [Pitch length mm]-[Pitch]M-[Width mm] | 560-8M-20 | 560 mm pitch length, 8M, 20 mm wide |
| GT3 / Poly Chain | [Pitch]MGT-[Pitch length mm]-[Width mm] | 8MGT-640-36 | 8 mm GT3, 640 mm pitch length, 36 mm wide |
| T-Profile | [Pitch length mm]-T[Pitch]-[Width mm] | 455-T5-25 | 455 mm pitch length, T5, 25 mm wide |
| AT-Profile | [Pitch length mm]-AT[Pitch]-[Width mm] | 660-AT10-32 | 660 mm pitch length, AT10, 32 mm wide |
Commonly Confused Profiles
Several timing belt profiles share the same pitch number but use completely different tooth shapes. These are the most common sources of ordering errors. Mixing them will cause belt failure.
| Pitch | Profile A | Profile B | Interchangeable? | Key Difference |
|---|---|---|---|---|
| 5 mm | 5M (HTD) | T5 (Metric Trapezoidal) | No. Different tooth shape, different pulleys. | 5M is curvilinear with 2.1 mm tooth height. T5 is trapezoidal with 1.2 mm tooth height. |
| 5 mm | 5M (HTD) | AT5 (Advanced Trapezoidal) | No. Different tooth shape, different pulleys. | 5M is curvilinear. AT5 is modified trapezoidal. |
| 5 mm / 5.08 mm | 5M (HTD, 5.000 mm) | XL (Imperial, 5.080 mm) | No. Different tooth shape, different pitch. | Pitches differ by 0.08 mm. Tooth shapes are completely different (curvilinear vs. trapezoidal). |
| 10 mm | T10 (Metric Trapezoidal) | AT10 (Advanced Trapezoidal) | No. Different tooth geometry. | AT10 has a modified tooth form. T10 pulleys and AT10 pulleys are not interchangeable. |
| 8 mm | 8M (HTD) | 8MGT (GT3) | Partially. GT3 can run on HTD pulleys (reduced performance). HTD should not run on GT3 pulleys. | GT3 tooth is optimized for tighter mesh. Best performance requires matched pulley sets. |
For a full explanation of every profile family and how they differ, see our Timing Belt Tooth Profiles Explained guide.
How to Measure Timing Belt Pitch
If you have a belt with no readable markings, you can measure the pitch directly:
- Method 1 (most accurate): Count 10 consecutive teeth. Measure the distance from the center of the first tooth to the center of the 11th tooth (this spans 10 pitches). Divide the total distance by 10. This averages out measurement error.
- Method 2 (quick check): Measure from the center of one tooth to the center of the adjacent tooth using calipers. This gives you the pitch directly, but is less accurate on worn belts.
- Important: Measure along the pitch line (the neutral plane where the tensile cord sits, near the base of the teeth), not along the outer or inner surface of the belt.
Once you have the pitch measurement, match it to the closest value in the master chart above. If the measurement falls between two standard pitches, the belt is likely the nearer standard pitch and the discrepancy is due to wear or measurement technique. For help identifying a belt from measurements, call Texas Belting at 888-203-2358.
Frequently Asked Questions
Pitch is the distance from the center of one tooth to the center of the next tooth, measured along the belt's pitch line. The pitch line sits at the tensile cord (near the base of the teeth), not at the outer or inner surface. Pitch determines tooth size and spacing, and it must match the pulley groove spacing exactly.
No. Although both have a 5 mm pitch, the 5M is an HTD curvilinear profile and the T5 is a metric trapezoidal profile. Their tooth shapes are different, their pulleys are different, and they are not interchangeable. Using a T5 belt on a 5M pulley (or vice versa) will cause rapid failure. Always confirm the full profile designation, not just the pitch number.
Count 10 consecutive teeth and measure the distance from the first tooth center to the 11th tooth center. Divide by 10 to get the pitch. Then examine the tooth shape: straight-sided tapered teeth indicate trapezoidal, rounded teeth indicate curvilinear (HTD or GT). Match the pitch and tooth shape to the charts above to identify the profile. You can also call Texas Belting at 888-203-2358 with your measurements and we will identify the belt for you.
For curvilinear belts, 8M (8 mm HTD) is the most widely used pitch in general industrial applications, followed by 5M. For imperial trapezoidal belts, L (3/8 inch) and XL (1/5 inch) are the most common. The 2 mm GT2 pitch dominates the 3D printing and small automation market.
No. The belt pitch must match the pulley groove pitch exactly. A belt with a different pitch will not mesh correctly and will fail immediately or cause rapid tooth wear. If you need to change the belt pitch (for example, upgrading from trapezoidal to curvilinear for better performance), you must also replace the pulleys.
Pitch length is the total length measured along the belt's pitch line (at the tensile cord, near the base of the teeth). This is the specification used in part numbers and for ordering. The outside circumference and inside circumference are both different from the pitch length. Always order timing belts by pitch length, not by measuring the outside with a tape measure.
Yes. Send us a photo of the belt (showing the teeth and any visible markings) along with your pitch measurement and belt width, and we can identify the profile and recommend the correct replacement. Call 888-203-2358 or submit through our contact form.
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Can't Identify Your Timing Belt?
Send us your part number, measurements, or a photo and Texas Belting will identify the correct profile, pitch, and replacement belt. We cross-reference Gates, Continental, Bando, Megadyne, Diesel Belting, and OEM part numbers.
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