Ultimate Guide: How To Fix Tension On A Sewing Machine

Sewing machine tension is like a delicate dance between the top thread and the bobbin thread. When this dance is off, stitches look messy, fabric puckers, or stitches might even fall out. If you’re asking how to fix tension on a sewing machine, the answer is usually to check your threading first, then look at your tension dials and possibly the bobbin area. Learning to adjust sewing machine tension is a key skill for anyone who sews, helping you solve many sewing machine tension problems quickly.

How To Fix Tension On A Sewing Machine
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What is Sewing Machine Tension?

Think of sewing machine tension as the pull on your thread. Your machine has two threads working together to make a stitch: the top thread and the bottom thread (from the bobbin).

When you sew, the top thread goes down through the fabric, makes a loop, and the bobbin thread goes through that loop. Then the machine pulls the threads tight. A good stitch happens when the top and bottom threads pull equally. They lock together neatly in the middle of the fabric layers.

If the tension is wrong, the threads won’t lock in the middle.

Signs Your Tension is Off

Bad tension shows up in a few ways. Here are the most common signs:

Looping Stitches on Top: If you see loops of thread on the top side of your fabric, your bobbin tension might be too loose, or more commonly, your top tension is too tight.
Looping Stitches Underneath Fabric: This is a very common problem. You sew along, and the top looks fine, but when you turn the fabric over, you see loose loops on the bottom. This usually means your top thread tension is too loose, or something is wrong with your top threading path.
Fabric Puckering: If the fabric is gathering or wrinkling along the stitch line, the tension (usually the top tension) is probably too tight.
Stitches Breaking: If the thread keeps snapping, the tension might be too tight.
Skipped Stitches: Sometimes, tension issues can even cause your machine to skip stitches.

Why Tension Goes Wrong

Tension problems don’t just happen out of nowhere. There’s usually a simple reason. Most sewing machine tension problems are not actually caused by the tension dial itself! Here are common culprits:

Threading Mistakes: This is the number one reason. If the top thread isn’t in the tension discs correctly, or if the bobbin isn’t put in right, tension goes haywire.
Dirt and Lint: Fluff and thread bits can get stuck in the tension discs or in the bobbin case area. This stops the thread from moving freely. Clean sewing machine tension discs regularly.
Wrong Needle or Thread: Using a needle that’s too big or too small for the thread or fabric can mess up tension. Using poor quality thread that isn’t smooth can also cause issues.
Bobbin Problems: The bobbin might be wound unevenly, it might be the wrong size for your machine, or the bobbin case itself might have lint or damage.
Machine Needs Cleaning/Oiling: A machine that isn’t cared for won’t work right. Tension parts need to be clean and sometimes oiled.
Incorrect Tension Settings: While less common as the initial cause, having the tension dial set completely wrong for your fabric and thread will cause problems.

Basic Checks Before Adjusting Tension

Before you even think about touching that tension dial, do these important checks. Many times, these steps will fix your tension problems right away without any need to adjust sewing machine tension. These are crucial steps to troubleshoot sewing machine stitches.

H4: Check Your Thread and Needle

Is the thread good quality? Cheap or old thread can be weak, break easily, or have slubs that get caught.
Is the needle new? A bent or dull needle causes all sorts of stitch problems, including tension ones.
Is the needle the right size for the thread and fabric? Thicker threads need bigger needles. Delicate fabrics need finer needles. Check your machine manual or thread spool for suggestions.
Is the needle put in correctly? Needles have a flat side that usually faces the back on most machines. Make sure it’s pushed all the way up.

H4: Check the Bobbin

Is the bobbin wound evenly? It should look smooth, not lumpy or loose in spots. If it’s uneven, re-wind it.
Is the bobbin put in the bobbin case or machine correctly? Check your manual. There’s a specific direction it needs to spin and a specific way the thread needs to come out.
Is it the right bobbin for your machine? Bobbins look similar but can be different sizes or shapes. Using the wrong one will cause major problems.
Is the bobbin area clean? Take out the bobbin and bobbin case. Use a brush to remove all lint and thread bits. This is part of clean sewing machine tension discs but applies to the lower part too.

H4: Re-thread the Machine Completely

This is the MOST important step. A simple mistake in threading is the most common cause of tension problems.

Lift the presser foot: This opens the tension discs on the top. If the foot is down, the discs are closed, and you can’t seat the thread correctly.
Pull out both the top and bobbin threads.
Thread the top thread again slowly. Follow the numbers or diagrams on your machine. Make sure the thread pops into the tension discs firmly. Don’t let the thread get snagged on anything.
Insert the bobbin again. Make sure the thread goes through any guides on the bobbin case or machine correctly.
Pull the bobbin thread up. Hold the top thread end lightly, turn the handwheel towards you one full stitch cycle. The top thread should catch the bobbin thread and pull a loop up through the needle plate hole. Pull both threads under the presser foot and towards the back.

H4: Clean Under the Needle Plate

Unscrew or unclip the needle plate.
Remove the bobbin and bobbin case.
Use a small brush (the one that came with your machine is best) to brush away all the lint, dust, and thread snippets. Pay special attention to the area around the feed dogs and where the bobbin sits.
You can also use a small vacuum attachment or canned air (use carefully, as it can blow dust into the machine).
Put everything back together correctly.

H4: Test on Scrap Fabric

Use two layers of the same fabric you plan to sew. Use the same thread. Sew a few lines of straight stitches. Look at the stitches on both the top and bottom. This helps you see if the problem is fixed or if you need to adjust further.

Adjusting Upper Thread Tension

Okay, you’ve done all the basic checks, but your stitches still look wrong. Now you can think about the tension dials.

Most sewing machines have one main dial for the upper thread tension. It usually has numbers on it. A medium number (like 3, 4, or 5) is the standard setting for average fabrics.

H5: Finding the Upper Tension Dial

The upper tension dial is usually a round knob on the front or top of your machine. It will have numbers around it.

H5: How Upper Tension Works

When the upper thread goes through the machine, it passes between two metal discs (the tension discs). The tension dial controls how tightly these discs press together.

Higher numbers: Make the discs press tighter. This adds more tension to the top thread.
Lower numbers: Make the discs press looser. This adds less tension to the top thread.

H5: When to Adjust Upper Tension

If you have looping stitches underneath fabric (top thread too loose), you need to increase the upper tension. Turn the dial to a slightly higher number.
If your fabric is puckering or the stitches look too tight on the top, you need to decrease the upper tension. Turn the dial to a slightly lower number.

H5: How to Adjust Upper Tension

Make Small Changes: Don’t jump from 4 to 8! Move the dial just one number at a time.
Test After Each Change: Get your scrap fabric. Sew another line of stitches. Check how they look.
Keep Testing: Keep adjusting by small amounts and testing until the stitches look balanced.

Remember to always re-thread with the presser foot UP before testing your tension settings.

Adjusting Bobbin Tension

Bobbin tension is controlled by a small screw on the bobbin case (for machines with removable bobbin cases) or is factory set on drop-in bobbin systems.

Important Rule: You almost never need to adjust bobbin tension. It is set at the factory and rarely changes unless the bobbin case is dirty, damaged, or you are doing special techniques like free motion embroidery or using very thick thread in the bobbin. Bobbin tension adjustment should be your last resort after trying everything else.

H5: Adjusting Bobbin Tension on a Removable Bobbin Case

Take the bobbin case out of the machine.
Find the small screw on the side of the case. There are usually two screws, but one is smaller and controls tension. Do NOT touch the larger screw.
To increase bobbin tension (if you have loops on the top of the fabric), turn the small screw a tiny bit clockwise (right).
To decrease bobbin tension (if the bottom thread looks too tight), turn the small screw a tiny bit counter-clockwise (left).
A tiny turn is like the size of a minute mark on a clock face. Small adjustments are key.
Test the bobbin tension using the “drop test” or “finger test”: Put the bobbin in the case. Hold the thread coming from the case. The case should hang freely. If you give it a gentle tug or slight flick of your wrist, it should drop just an inch or two and stop. If it drops freely, it’s too loose. If it doesn’t drop at all, it’s too tight.
Put the bobbin case back in the machine and test stitch on scrap fabric.

H5: Adjusting Bobbin Tension on a Drop-in Bobbin

Most drop-in bobbin systems do not have an easy way for the user to adjust the tension. If you suspect the bobbin tension is the problem here, make absolutely sure you have done all the basic checks first (especially cleaning the bobbin area very well). If problems continue, it might be a job for a repair person.

Achieving Balance Sewing Machine Tension

The goal is to have the top and bottom threads pull evenly so they meet and lock in the center of the fabric layers. On the top of the fabric, you should see nice, even stitches. On the bottom, you should see the same nice, even stitches. The threads should not show on the opposite side.

H5: What Balanced Tension Looks Like

On a piece of scrap fabric (using a contrasting color bobbin thread helps), sew a straight line.

Perfect Tension: The stitches look the same on the top and the bottom. You can’t see the bobbin thread loops on the top, and you can’t see the top thread loops on the bottom. The threads meet inside the fabric.

H5: Testing for Balance

Sew a stitch line and examine it closely.

If you see dots of the bobbin thread showing on the top side, the top tension is too tight or bobbin tension is too loose.
If you see dots of the top thread showing on the bottom side, the top tension is too loose or bobbin tension is too tight.
If there are loops on the bottom, top tension is too loose.
If there are loops on the top, bobbin tension is too loose (or top tension is too tight).

Your aim is to find the correct sewing machine tension settings for your specific fabric, thread, and stitch type. This setting might be different for different projects.

Step-by-Step Guide to Fixing Tension

Here’s a plan to follow when you have sewing machine tension problems:

Stop Sewing: Don’t keep sewing with bad tension; it won’t fix itself.
Identify the Problem: Look at your stitches. Are the loops on top or bottom? Is the fabric puckering? This helps you know where to start. (e.g., looping stitches underneath fabric usually means top tension is too loose).
Do ALL Basic Checks:
- Check the needle (right size, inserted correctly, not bent).
- Check the thread (good quality, right type for fabric/needle).
- Check the bobbin (wound evenly, right type, inserted correctly).
- Re-thread the entire machine (top and bobbin, presser foot UP). This fixes most problems.
- Clean under the needle plate and around the bobbin area. Clean sewing machine tension discs by threading with the presser foot up and then pulling a piece of thread through firmly while holding the discs lightly, or use a brush.
Test Stitch: Sew on two layers of scrap fabric.
Look at the Test Stitch: Is the problem gone? Great! If not, move to step 6.
Adjust Upper Tension:
- If loops are on the bottom (top thread too loose), turn the upper tension dial to a slightly higher number (e.g., from 4 to 5).
- If loops are on the top (bobbin thread too loose OR top thread too tight) OR fabric is puckering (top thread too tight), turn the upper tension dial to a slightly lower number (e.g., from 4 to 3).
Test Stitch Again: Sew another line on your scrap fabric.
Repeat: Keep making small adjustments (one number at a time) to the upper tension and testing until the stitch looks good on both sides. Most tension problems are fixed by adjusting the upper tension dial.
Consider Bobbin Tension ONLY IF: You have adjusted the upper tension significantly in both directions (very loose, very tight) and still cannot get a balanced stitch, AND you have a removable bobbin case, AND you have ruled out ALL other causes (threading, cleaning, needle, thread).
- If you decide to adjust bobbin tension (with caution!):
  - Take out the bobbin case.
  - Turn the small screw a tiny amount (like a minute mark).
  - Test with the “drop test”.
  - Put back in machine and test stitch.
  - Repeat small adjustments and testing until the bobbin tension seems right, then go back and fine-tune the upper tension.
Document Settings: Once you find the right settings for a specific fabric/thread combination, make a note of it. Your machine’s standard setting is a good starting point for most projects.

By following these steps, you can effectively balance sewing machine tension and resolve most stitch issues.

Common Tension Problems and How to Fix Them

Let’s look at specific problems and the typical fixes. This helps you correct sewing machine tension settings.

Problem	What it Looks Like	Most Likely Cause(s)	How to Fix (In Order)
Loops on Bottom	Loops of top thread visible on underside. Top looks okay.	Upper tension too loose; Top thread threaded wrong; Lint in tension discs.	1. Re-thread top. 2. Clean top tension discs. 3. Increase upper tension (higher number).
Loops on Top	Loops of bobbin thread visible on topside. Bottom looks okay.	Bobbin tension too loose; Bobbin wound wrong; Bobbin case issue; Upper tension too tight.	1. Check bobbin winding/insertion. 2. Clean bobbin area. 3. Decrease upper tension (lower number). 4. Very carefully slightly tighten bobbin tension (if removable case).
Fabric Puckering	Fabric gathers or wrinkles along the stitch line.	Tension too tight (usually upper); Wrong stitch length/type for fabric; Incorrect stabilizer.	1. Decrease upper tension (lower number). 2. Check stitch length (should not be too short). 3. Use stabilizer for delicate fabric.
Thread Breaking (Top)	Top thread keeps snapping.	Tension too tight; Poor quality thread; Needle bent/wrong size; Rough spot on machine.	1. Decrease upper tension. 2. Change thread. 3. Change needle. 4. Check machine for snags.
Thread Breaking (Bobbin)	Bobbin thread keeps snapping.	Bobbin tension too tight; Bobbin wound wrong/too full; Lint in bobbin case; Poor quality thread.	1. Check bobbin winding/insertion. 2. Clean bobbin area. 3. Very carefully slightly loosen bobbin tension (if removable case). 4. Change thread.
Skipped Stitches	Machine misses forming loops.	Wrong needle size/type; Needle bent/inserted wrong; Threading issue; Tension slightly off.	1. Change needle (most common fix for skips). 2. Check needle insertion. 3. Re-thread. 4. Adjust tension slightly.

This table summarizes common sewing machine tension problems and helps you figure out where to start to correct sewing machine tension settings.

Keeping Your Machine Happy: Maintenance Prevents Tension Issues

Regular cleaning and care are the best ways to prevent most sewing machine tension problems.

Clean Often: After every project or every few hours of sewing, clean out the bobbin area and under the needle plate. Use a small brush.
Clean Tension Discs: While not always easy to access for deep cleaning, regularly re-threading with the presser foot up and gently pulling thread through helps remove light dust. Some machines have a small brush you can use near the discs. Clean sewing machine tension discs as part of your routine.
Use Good Quality Thread: Quality thread is smoother and creates less lint.
Change Your Needle: Change your needle for every new project, or after about 8-10 hours of sewing. Needles get dull or slightly bent, which affects stitch quality and tension.
Oil Your Machine: Follow your machine’s manual for oiling points and how often to oil. A well-oiled machine runs smoother, reducing stress on threads and tension parts.
Use the Right Settings: Get used to the standard tension setting for your machine. Only change it when needed for different fabrics or threads.

When to Get Professional Help

You’ve tried everything: re-threading, cleaning every reachable part, changing needle and thread, adjusting upper tension, and maybe even slightly adjusting bobbin tension (if you could). But the tension is still wrong.

This might be a sign of a problem you can’t fix yourself. The tension discs could be damaged, there might be something stuck deep inside the machine, or the bobbin case might be damaged.

If you’ve gone through all the troubleshooting steps and your machine still won’t sew a balanced stitch, it’s time to take it to a sewing machine repair shop. They have the tools and knowledge to fix internal issues and reset tension to factory settings.

Frequently Asked Questions (FAQ)

H5: What is the best tension setting for a sewing machine?

There is no single “best” setting. It depends on the fabric and thread you are using. A medium setting (like 3, 4, or 5) is a good starting point for average cotton fabric and polyester thread. Always test on scrap fabric.

H5: Why are my stitches looping on the bottom?

This is almost always because the top thread tension is too loose or the top thread is not correctly threaded through the tension discs. Re-thread the machine completely with the presser foot UP. If it still happens, increase your upper tension setting one number at a time and test.

H5: Why are my stitches looping on the top?

This usually means the bobbin tension is too loose, or the upper tension is too tight. First, decrease the upper tension slightly. If that doesn’t fix it, check that your bobbin is wound evenly and inserted correctly. If you have a removable bobbin case, you might need to tighten the small screw on it very slightly.

H5: Should I ever touch the screw on the bobbin case?

Ideally, no. Bobbin tension is set at the factory and should not need adjusting unless you have a specific reason (like free motion quilting with a different thread) or suspect the bobbin tension is truly off after trying all other fixes. If you do adjust it, make very small turns.

H5: Does thread quality affect tension?

Yes, absolutely. Cheap or old thread can have slubs, uneven thickness, or be weak. This prevents the thread from flowing smoothly through the machine and tension discs, leading to problems. Use good quality thread from a reputable brand.

H5: How often should I clean my sewing machine?

Clean the bobbin area and under the needle plate after every few hours of sewing or after finishing a project. A deeper cleaning and oiling schedule should follow your machine’s manual, often every few months depending on use. Regular cleaning prevents lint build-up that causes tension issues.

H5: My machine was working fine, but now the tension is bad. What happened?

Most likely, something simple changed. Check your threading first – this is the most common reason. Then check the needle (it might be bent or dull) and the bobbin. Lint build-up is also a frequent culprit. Go through the basic troubleshooting steps first before adjusting tension dials.

Learning to troubleshoot sewing machine stitches and fix tension issues takes a little practice, but it’s a skill that will save you a lot of frustration. By following these steps, you can solve most common sewing machine tension problems and get back to enjoying sewing with beautiful, balanced stitches.