What a dart is and why you need it
A dart is a tapered seam that removes fabric from a garment to create shape and fit. Instead of loose fabric bunching at the bust, waist, or hip, a dart takes in that excess and angles it to a point, so the garment follows your body contours. Darts are what make a dress sit smoothly instead of hanging like a sack.
You will see darts marked on almost every fitted pattern — usually as a diamond or double-pointed line on the fabric. The wider end (called the base) sits on the edge of the garment; the point tapers inward. When you sew a dart, you fold the fabric so the two legs of the diamond meet, then stitch from the base to the point.
Darts appear most often at the bust, waist, and hip on dresses and blouses. Some patterns also use them at the shoulder or elbow for shaping. Learning to sew them cleanly is one of the fastest ways to move from loose-fitting garments to pieces that actually fit your shape.
Key Takeaways
- Mark both legs of the dart with tailor's chalk or a fabric pencil before you fold, so you have a clear line to follow when stitching.
- Fold the dart so the two marked lines meet exactly, then pin along the fold to hold it in place while you sew.
- Stitch from the wide base toward the point, tapering your stitches so the last few are right on the fold line for a sharp finish.
- Press the dart flat first, then to one side (usually toward the center of the garment), to set the seam and reduce bulk.
- Trim the seam allowance inside the dart to about one-quarter inch and finish the raw edges if your fabric frays.
Mark the dart before you fold
Start with your pattern piece pinned to the fabric. You will see the dart marked as two lines forming a diamond or triangle, with the point toward the center of the garment and the base on the edge. Using tailor's chalk or a fabric pencil, trace both legs of the dart directly onto the wrong side of the fabric. Mark the point as well — a small dot or cross is enough.
Marking both lines is the step most people skip, and it is the reason their darts come out crooked. If you only mark one line, you have to guess where the second line is when you fold, and your stitches will wander. With both lines marked, you have a clear target on both sides of the fold.
If your fabric is dark or the marks do not show well, use a tracing wheel and dressmaker's carbon paper instead. Lay the carbon paper (waxy side down) under the pattern, roll the wheel along the dart lines, and the marks will transfer to the fabric. This method works especially well on velvet, corduroy, and other napped fabrics where chalk can disappear.
Fold and pin the dart
Fold the fabric so the two marked lines lie exactly on top of each other. The fold will run from the base of the dart (on the edge of the garment) toward the point (in the center). Pin along the fold every inch or so, starting at the base and working toward the point. Make sure the marked lines stay aligned as you pin — if they slip, the dart will be lopsided.
Press the fold lightly with your fingers or a cool iron to crease it. This crease acts as a guide and keeps the layers from shifting while you sew. Do not use a hot iron yet; you will press the finished dart later.
Check that the base of the dart (the wide end on the edge of the garment) is square and even. This is where the dart starts, and if it is crooked, the whole dart will be off. The point should be sharp and the fold should taper smoothly from base to point with no bumps or wrinkles.
Stitch from base to point with a taper
Set your machine to a regular stitch length (about 2.5 mm) and thread it with thread that matches your fabric. Place the folded dart under the presser foot so the marked line on top is visible. Lower the presser foot and begin stitching at the base of the dart, right along the marked line.
Sew straight along the marked line for the first half to two-thirds of the dart. Then begin to taper your stitches inward, moving closer to the fold line with each stitch. By the time you reach the point, your stitches should be right on the fold itself — this creates the sharp point and prevents a bump at the tip. Sew the last two or three stitches right along the fold, then stitch off the edge of the fabric.
Do not backstitch at the point. Backstitching creates a knot of thread that can show or create a lump. Instead, leave thread tails about 4 inches long, remove the dart from the machine, and tie the tails together with a knot close to the fabric. Trim the tails to about one-quarter inch.
If your dart is very long or your fabric is thick, you can use a shorter stitch length (2 mm) for extra strength, but this is not necessary for most garments. A regular stitch is fine and is easier to remove if you need to fix it.
Press and trim the finished dart
Remove the pins and unfold the dart. Place it on your ironing board with the seam facing up. Press the seam flat to set the stitches and remove any wrinkles from folding. Use a medium heat setting and a pressing cloth if your fabric is delicate.
Fold the dart to one side — usually toward the center of the garment (so a bust dart folds down, a waist dart folds toward the side seam). Press again so the dart lies flat in its final position. This step is important because it shapes the dart and makes it less visible from the outside.
Trim the seam allowance inside the dart to about one-quarter inch. Use sharp scissors and cut close to the stitching line, being careful not to cut the stitches themselves. If your fabric frays (cotton, linen, or loosely woven fabrics), finish the raw edges with a zigzag stitch or a serger. If your fabric does not fray (knits, felt, or tightly woven fabrics), you can leave the edges as they are.
Common mistakes and how to fix them
The most common mistake is stitching a straight line instead of tapering to the point. This creates a bump or bubble at the tip of the dart. If this happens, you can carefully remove the stitches with a seam ripper, re-fold the dart, and stitch again with a proper taper. The second time, focus on moving your needle closer to the fold as you approach the point.
Another frequent problem is the two legs of the dart not meeting when you fold. This usually means the marked lines were not accurate or the fold was not creased sharply enough. Check your marks before you fold, and use pins to hold the lines together as you fold. If the lines still do not meet, unfold and re-mark using a ruler to make sure both legs are the same distance from the point.
If the dart looks crooked or off-center, the base was probably not square. The base should be perpendicular to the edge of the garment. If it is angled, the whole dart will angle with it. Check the pattern and re-mark if needed, making sure the base is at a right angle to the seam line.
Darts on different fabric types
On lightweight fabrics like cotton voile or linen, darts are straightforward and need no special handling. Stitch, press, trim, and you are done. On heavier fabrics like denim or canvas, use a shorter stitch length and consider using a topstitching needle (size 90 or 100) for extra strength. Trim the seam allowance a bit narrower to reduce bulk.
On stretchy fabrics like jersey or lycra, use a ballpoint needle and a slight zigzag stitch (width 0.5 to 1 mm) instead of a straight stitch. This allows the seam to stretch with the fabric and prevents it from breaking. Do not trim the seam allowance as close on knits; leave it at about half an inch to prevent the edges from curling.
On pile fabrics like velvet or corduroy, mark with a tracing wheel and carbon paper (chalk can disappear into the nap). Stitch with the pile running toward you so the presser foot does not push the nap backward. Press darts on these fabrics with a pressing cloth or a needle board to avoid flattening the pile.
Frequently Asked Questions
Can I sew a dart on the right side of the fabric instead of the wrong side?
No. Darts are always sewn on the wrong side so the seam is hidden inside the garment. If you sew on the right side, the stitching will be visible. The only exception is a decorative dart, which is intentionally stitched on the outside as a design detail, but that is a different technique.
What if my dart point goes past the marked line?
Stop stitching when you reach the marked point. Sew off the edge of the fabric at that spot, tie off the thread tails, and trim them. If you sew past the point, the dart will be too long and may create a pucker or distort the garment shape. Accuracy at the point is more important than at the base.
Do I have to press a dart, or can I skip that step?
Pressing is not optional if you want a professional finish. Pressing sets the stitches, removes wrinkles, and shapes the dart so it lies flat and looks smooth from the outside. A dart that is not pressed will look bumpy and unfinished, even if the stitching is perfect.
How many darts does a typical dress pattern have?
Most fitted dresses have four darts: two at the bust (one on each side) and two at the waist (one on each side). Some patterns add hip darts as well. Looser styles may have no darts or only one or two. Check your specific pattern for the number and placement.
What if I sew the dart in the wrong direction?
If you sew from the point toward the base instead of base to point, the dart will still work, but the taper will be backward and the point may not be as sharp. It is better to remove the stitches and sew it again in the correct direction (base to point) for a cleaner finish.