Start at factory default
Your machine has factory tension settings. Start there for new thread types and fabrics. Adjust only if test stitches show problems.
StitchPilot.aiReference · Thread tension
Embroidery Thread Tension Reference
Thread tension is the single most influential adjustment on an embroidery machine — it affects stitch appearance, durability, thread breaks, and fabric distortion. This guide covers how to test tension, adjust correctly, and recognize the symptoms of wrong tension.
Set and verify tension
Stitch a test piece
Stitch a small test piece on scrap fabric similar to your project. Look at the BACK of the stitches — that's where tension shows up clearly.
Look at the back: ⅓ top vs ⅔ bobbin
Right tension: back shows about ⅓ top thread, ⅔ bobbin thread. More top thread visible = top too tight. More bobbin visible = top too loose.
Adjust top tension first, then bobbin
Top tension is easily adjustable (dial). Bobbin tension is set at factory but can drift. Adjust ¼ turn at a time, retest.
Tension symptoms
Reading wrong tension
Match the symptom to the tension issue:
- Loops on the back: top tension too loose — tighten ¼ turn
- Top thread breaking: top tension too tight — loosen ¼ turn
- Bobbin showing through to front: top tension way too tight
- Puckered fabric: overall tension too tight, or wrong stabilizer
- Weak / floppy stitches: top tension too loose
When to re-test
Tension changes situations
Retest tension whenever:
- You switch thread brand (Madeira vs Isacord behave differently)
- You switch thread weight (40wt vs 60wt need different tension)
- You switch from polyester to rayon or metallic
- You change to a very different fabric (silk vs canvas)
- You replaced bobbin case or did machine service
Embroidery thread tension — common questions
How do I know if my embroidery thread tension is right?
Look at the back of a test stitch. ⅓ top thread visible and ⅔ bobbin thread = perfect. More top thread = top too tight. More bobbin = top too loose.
Should I adjust top or bobbin tension first?
Top tension. It's easily adjustable via the dial. Bobbin tension is set at factory and only needs occasional fine-tuning.
How often should I check embroidery tension?
Every time you switch thread brand, thread weight, or fabric type. Tension that works on cotton polo may be wrong for terry towels. A quick test stitch saves hours.
What causes embroidery thread to break frequently?
Top tension too tight is the second most common cause (after dull needle). Loosen ¼ turn and retest. See /guides/embroidery-thread-breaking for full diagnostic flow.
Can I damage my machine by adjusting tension wrong?
Top tension dial: no, just produces bad stitches until you readjust. Bobbin tension screw: yes, you can lose the screw or strip the threads. Adjust bobbin tension in small increments.
Confirm the design
Open the file in StitchPilot.ai first
If the design looks fine in the viewer, your tension/needle/stabilizer is the issue — much easier to diagnose.
Verify design before tension change →