Needle & Thread Size Selector
Match hand and machine needles to your thread — in mm, Tex or by stitch pitch.
Quick answer
Match your needle to your thread, not your leather. For hand saddle stitch, use a blunt harness needle sized so two strands of thread just pass through the hole — about a John James 002 for 0.6 mm thread. For machines, use a leather-point needle around Nm 110 (#18) for Tex 70 thread. Enter your thread size, Tex or stitch pitch below.
John James size 002
Needle follows thread
The needle exists to carry the thread through the hole, so you size it to the thread. For hand saddle stitch that means a blunt harness needle just big enough to pass two strands — sharp needles pierce and split the thread on the way back. Machine sewing uses a leather-point needle (LR/S) that cuts a small slit rather than punching a round hole, sized by the thread’s Tex number.
Needles & matching thread
For 0.6 mm thread.
-
Blunt Harness Stitching Needles (set)
- Size
- assorted sizes
- Level
- Beginner
Blunt tips slip between existing holes without splitting your thread on the return pass. Two per seam for saddle stitch.
-
John James Saddlers Harness Needles
- Size
- sizes 1-8
- Level
- Beginner
A quality blunt needle in graded sizes — pick the size that just passes two strands of your thread through the hole.
-
Waxed Polyester Thread 0.45 mm (Fine)
- Size
- 0.45 mm | ~180 m spool
- Pitch
- 2.7 mm
- Thread
- 0.45 mm
- Material
- Polyester
- Weight
- 2-4 oz
- Level
- Beginner
Braided, pre-waxed polyester in a fine diameter for tight pitches. Comparable to Meisi 0.45.
Reviewed 2026-06-30 -
Waxed Polyester Thread 0.55 mm (Fine-Medium)
- Size
- 0.55 mm | ~160 m spool
- Pitch
- 3.2 mm
- Thread
- 0.55 mm
- Material
- Polyester
- Weight
- 2-5 oz
- Level
- Beginner
Steps up from 0.45 mm for card holders and slim wallets stitched with 3.0–3.38 mm irons.
Reviewed 2026-06-30 -
Ritza 25 Tiger Thread 0.6 mm
- Size
- 0.6 mm | 25 m or 500 m
- Pitch
- 3.85 mm
- Thread
- 0.6 mm
- Material
- Polyester
- Weight
- 3-7 oz
- Level
- Beginner
The default beginner thread — flat, pre-waxed polyester that lies neat and rarely frays. Great for wallets and small bags.
Reviewed 2026-06-30
Thread → needle size chart
| Thread | Tex | Hand needle | Machine needle | Typical use |
|---|---|---|---|---|
| 0.45 mm | Tex 40 | John James size 004 (fine) | Nm 90 / #14 | Watch straps, fine small leather goods |
| 0.55 mm | Tex 60 | John James size 002 | Nm 100 / #16 | Card holders, slim wallets |
| 0.6 mm | Tex 70 | John James size 002 | Nm 110 / #18 | Wallets, small bags |
| 0.8 mm | Tex 90 | John James size 1 | Nm 120 / #19 | Bags, totes, straps |
| 1.0 mm | Tex 138 | John James size 0 | Nm 140 / #22 | Belts, heavy totes |
| 1.2 mm | Tex 207 | John James size 0 / big-eye | Nm 160 / #23 | Heavy-duty, harness work |
Tex and needle sizes are practical guidance; brands vary. Hand needles just need to pass two thread strands through the hole.
Frequently asked questions
What size needle for leather hand stitching?
Use a blunt harness needle sized so two strands of your thread pass through the hole — roughly a John James size 002 for 0.6 mm thread. Sharp needles split the thread on the return pass.
What machine needle for leather?
Match the needle to your thread weight and use a leather-point (LR or S) needle. For Tex 70 bonded thread, an Nm 110 (#18) leather point is a good start.
How do I convert thread mm to Tex?
They are two ways to describe thread thickness. As a rough guide, 0.6 mm ≈ Tex 70, 0.8 mm ≈ Tex 90, 1.0 mm ≈ Tex 138. Use the chart above to convert.
What thread and needle for 3.85 mm irons?
0.6 mm thread (about Tex 70) with a John James 002 blunt needle suits 3.85 mm pitch. See the stitch pitch converter to confirm.