Every embroidery design is built from a handful of stitch types. The two you'll run into constantly are satin stitch and fill stitch. Most of the time the choice between them isn't a matter of taste — it's decided by how wide the shape is, and getting it wrong is the single most common reason a design looks rough once it comes out of the hoop.
In this guide
Quick comparison
| Stitch type | How it works | Best for | Typical size range |
|---|---|---|---|
| Satin stitch | Tight zig-zag stitches spanning the full width of a shape | Borders, outlines, text, and narrow shapes | 2.5mm to ~12mm wide |
| Fill stitch | Rows of short stitches packed together to cover an area | Large solid areas, backgrounds, and broad shapes | Anything wider than ~10mm |
| Run stitch | A simple single line of stitches | Fine outlines, detail lines, and lightweight accents | Shapes too thin for satin (under ~2.5mm) |
Satin stitch: how it actually works
A satin column is defined by two rails — the two long edges of the shape — and the machine lays a stitch across the gap between them, back and forth, like the rungs of a very tight ladder. Because every stitch spans the full width in one unbroken pass, the thread lies flat and parallel, and that's what produces satin's characteristic sheen. Nothing else in embroidery looks quite like it.
That same property is also its limitation. A single stitch is a single straight span of thread with nothing holding down its middle. Make the span too long and there is simply nothing keeping it against the fabric.
The width rule (2.5mm to about 12mm)
Satin has a floor and a ceiling, and both are physical rather than stylistic.
The floor is around 2.5mm. Below that, the two rails are so close together that the needle penetrations on either side start landing in nearly the same holes. The result is a perforated line in the fabric and a column that looks like a thin cord rather than a stitched shape. click-stitch enforces this directly: a shape narrower than 2.5mm gets converted to a run stitch instead of a satin column, because a single clean line reads better than a satin that was never wide enough to be one.
The ceiling is around 10–12mm. Past that, each stitch is a long unsupported float of thread. It snags on fingers, zips, and washing machines; it sags; and it lets the fabric show through when the piece flexes. If you need a solid area wider than about 12mm, that's fill stitch's job — or split the shape into two narrower satin columns.
Fill stitch: coverage, spacing and angle
Fill stitch solves the float problem by giving up the single long span. Instead it lays down rows of short stitches, each one anchored at both ends, packed closely enough that the rows read as a solid block of colour. It's flatter and less glossy than satin, but it's stable at any size.
Two settings govern how a fill looks:
- Row spacing (density) — how far apart consecutive rows sit. Too far apart and the fabric grins through between rows. Too close and you're forcing an excessive amount of thread into a fixed area, which stiffens the design into a patch of cardboard and can pucker or even tear lightweight fabric.
- Stitch angle — the direction the rows run. This matters more than people expect. Thread reflects light along its length, so two adjacent shapes filled at different angles will read as visibly different shades of the same colour. Digitizers use this deliberately to separate overlapping shapes without a colour change — and get bitten by it accidentally when a single logical area gets split into pieces filled at different angles.
Fill is also where the needle penetrations end up doing structural work. A large fill area pulls the fabric inward from all sides as it stitches, which is what makes stabiliser and underlay non-negotiable on anything bigger than a coin.
Underlay: the part most guides skip
Underlay is a layer of stitching sewn underneath the visible top stitching. You never see it in the finished piece, and it is the difference between a design that looks professional and one that looks homemade. It does three jobs: it anchors the fabric to the stabiliser so the fabric can't shift mid-design, it flattens the pile on textured fabrics like fleece and terry so the top stitches don't sink into it, and it gives the top layer something to sit on so it stands slightly proud.
There are three common patterns, and the right one depends on what's going on top:
- Center-walk — a single line of running stitch straight down the middle of a satin column. The lightest option; used on narrow columns where anything more would show through at the edges.
- Contour — running stitch that traces just inside both rails of the column. Holds the edges crisp, which is what you want on lettering and patch borders.
- Zigzag — a loose, wide-spaced zig-zag under the full width of the column. The heaviest option, for wide satins and for knits or pile fabrics that need real stabilising.
Fill areas get their own underlay pass, usually a widely-spaced fill running at an angle to the top layer so the two don't sink into the same needle holes. click-stitch generates all of these automatically based on the stitch type and shape size — you don't set them by hand, but it's worth knowing they're there when you're wondering why a design has more stitches than you expected.
Pull compensation and why shapes come out thin
Thread under tension pulls the fabric inward as it stitches. The practical consequence: a satin column digitized at exactly 4mm wide sews out narrower than 4mm, and you get a hairline gap where it was supposed to meet the shape next to it. Pull compensation is the fix — the digitized shape is deliberately made slightly wider than the intended finished size so that it lands correctly after the fabric draws in.
How much compensation a design needs depends on the fabric. Stable woven fabrics barely move; knits, fleece and anything stretchy move a lot. This is the single most common reason a design that stitched perfectly on a cotton tote comes out with gaps on a polo shirt.
Choosing, shape by shape
Working through a design, the decision usually goes like this:
- Outlines and borders — satin, almost always. A stitched border is by definition a narrow shape, and satin's clean edge is exactly what a border is for. This is why nearly every patch has a satin edge; see the patch digitizing guide.
- Lettering — satin, until the letters get big. A letter stroke is a narrow shape, and satin is what keeps it legible at small sizes. Past roughly an inch of cap height the strokes get wide enough that fill becomes the better choice. See the monogram and font guide for how this interacts with font choice.
- Large solid shapes — fill. No judgement call needed.
- Long thin shapes — satin if they're at least 2.5mm wide, run stitch if they're thinner. Whiskers, stems, wire-frame details and single-line drawings all land here; outline mode is built specifically for designs made entirely of these.
- Shapes that vary in width — the awkward case. A teardrop or a brush-script letter is satin at one end and fill-width at the other. The usual answer is to split it, satin the narrow part and fill the wide part, and hide the seam where the shape changes direction.
Troubleshooting a bad sewout
| What you see | Usual cause | Fix |
|---|---|---|
| Loose, snaggy threads across a wide shape | Satin used past its width ceiling | Switch that shape to fill, or split it into two columns |
| A perforated line, fabric tearing along a thin shape | Satin used below ~2.5mm; needle hitting the same holes | Widen the shape, or let it fall back to run stitch |
| Fabric visible between rows of a solid area | Fill density too low, or no underlay on a pile fabric | Increase density slightly; check stabiliser |
| Design is stiff, board-like, or puckered | Fill density too high for the fabric | Reduce density; heavier fabric or lighter stabiliser |
| Hairline gaps between adjacent shapes | Pull compensation too low for a stretchy fabric | Expect this on knits; overlap adjacent shapes slightly |
| Two halves of one shape look like different colours | The shape was split and filled at two different angles | Match the fill angle across both halves |
How click-stitch chooses stitch type
Quick Convert makes the call for you: fill stitch on larger shapes, satin on borders and narrow areas, run stitch on anything below the satin floor. For most logos and simple designs that's the right answer without any input.
When you want to override it, the guided Wizard and Full Editor expose the choice per shape — you can force a shape to satin, force it to fill, adjust density, or wrap a satin border around the whole design. You can also check the result before you sew it: the stitch simulator opens a finished PES, DST or JEF in the browser and replays it stitch by stitch, which will show you a too-wide satin or a too-sparse fill far more reliably than a static preview.
Common questions
Is satin stitch stronger than fill stitch? No — the opposite, at width. Fill anchors every stitch at both ends, so it survives wear better across a large area. Satin is more durable than fill only in the narrow range it's designed for, where its unbroken spans resist fraying at an edge.
Does satin use more thread? Per unit of area, yes, noticeably. That's part of why an all-satin design takes longer to sew and costs more in thread than the same design filled.
Can I use satin for a large background? Not in one piece. You can get a satin-like appearance over a large area by splitting it into a series of narrow columns, but that's a deliberate decorative effect with a lot of colour-change and travel overhead, not a substitute for fill.
What about 3D puff? Puff embroidery is satin stitched over a foam layer, which is why puff designs are almost always bold block lettering — the technique only works within satin's width range, and needs higher density than flat satin to perforate the foam cleanly.
New to digitizing altogether? Start with embroidery digitizing for beginners for the full glossary of terms, then come back here when you're ready to control stitch types yourself.