Cushions and pillows are the most satisfying sewing projects for beginners — they're finished in an afternoon, they make an instant visual impact in a room, and they use relatively little fabric. But the yardage varies dramatically by style. A simple 16" knife-edge throw pillow uses half a yard. A box cushion with a zipper and welting can use two full yards. Here's exactly how much you need for each type.
1. Knife-Edge Throw Pillows: Two Squares, One Seam
A knife-edge pillow is the simplest style — two identical squares or rectangles sewn together around the edge with a sharp (un-welted) seam. No boxing strip, no gusset, just front and back.
The formula: Cut two pieces at (pillow form size + 1") for a 1/2" seam allowance all around. So a 16" pillow form needs two 17" squares.
| Pillow Form Size | Cut Size (Each Square) | Fabric Needed | Fits on 45" Fabric? |
|---|---|---|---|
| 16" x 16" | 17" x 17" | 0.5 yard | Yes — two across |
| 18" x 18" | 19" x 19" | 0.6 yard | Yes — two across |
| 20" x 20" | 21" x 21" | 0.7 yard | Yes — two across |
| 22" x 22" | 23" x 23" | 0.8 yard | Yes on 54" fabric; tight on 45" |
| 24" x 24" | 25" x 25" | 1.0 yard | Needs 54" fabric for two across |
| 12" x 20" (lumbar) | 13" x 21" | 0.5 yard | Yes — two across |
Pro tip: Add an invisible zipper along the bottom seam for a removable cover. The yardage doesn't change — you're still cutting two squares — but you'll need a zipper that's 2" shorter than the pillow width.
2. Box Cushion With Zipper: The Complete Formula
A box cushion has five fabric pieces: top panel, bottom panel, boxing strip (the sidewall that wraps around the perimeter), and a zipper panel in the back section of the boxing strip. These are the cushions you find on dining chairs, window seats, and patio furniture.
The formula (all dimensions include 1/2" seam allowance; add 1" to each foam dimension):
Bottom panel: (width + 1") x (depth + 1") — same as top
Boxing strip: (2 x width + 2 x depth + 4") long, (thickness + 1") wide — the extra 4" in length gives you seam allowance at the ends where the strip meets itself
Zipper: Install along the back half of the boxing strip — length = depth + 2"
Example — 22" x 22" x 3" chair cushion:
- Top and bottom: 23" x 23" each (two pieces)
- Boxing strip: (44" + 44" + 4") = 92" long by 4" wide
- Zipper: 22" + 2" = 24" long, installed in the back boxing section
- Total fabric: approximately 1.5 yards on 54" fabric (top and bottom fit two across at 23", boxing strip runs along the length)
For thicker foam (4" or 5"), the boxing strip gets wider and you may need to piece it together from multiple strips. For cushions deeper than 30", you'll likely need to seam the boxing strip from multiple widths. For exact calculations on your specific dimensions, use our Cushion Fabric Yardage Calculator.
3. Bolster Pillow: Cylinder Body + Two Circles
A bolster pillow is a cylinder — a rectangular body piece plus two circular ends. It's the geometry that trips people up, but the yardage is straightforward once you break it down.
The formula:
- Body rectangle: (circumference + 1") long x (length + 1") wide. Circumference = diameter x 3.14 (pi). So a 6" diameter x 18" long bolster needs a body piece of (6 x 3.14 + 1) = 19.8" by 19" — about 20" x 19".
- Two circle ends: diameter + 1" each. For a 6" bolster, cut two 7" circles.
- Total fabric: approximately 0.6 yards on 45" fabric for a standard 6" x 18" bolster — the body rectangle and both circles fit easily across the width.
Piping cord length for bolster: You need piping around both circle seams (2 x circumference = 2 x 18.8" = about 38" per bolster) plus the lengthwise seam if you want a piped body. Buy 1.5 yards of piping cord per standard bolster.
4. Floor Cushions: Big, Thick, and Worth the Fabric
Floor cushions are essentially oversized box cushions with thicker foam (4-6" is common). They're generous and comfortable but use proportionally more fabric because of the deep boxing strip.
For a 30" x 30" x 5" floor cushion:
- Top and bottom panels: 31" x 31" each
- Boxing strip: (120" + 4") = 124" long by 6" wide — that's over 3 yards of strip alone
- Total fabric: approximately 2.0-2.5 yards on 54" fabric
For an extra-large 36" floor cushion, budget 2.5-3.0 yards. Floor cushions are a great project for bold, large-scale prints — the big panels show off the pattern beautifully without the matching complexity that curtains bring.
5. Piping and Welting: How Much Extra Fabric?
Self-piping (welting made from the same fabric as the cushion) adds both a polished look and extra yardage. Here's how to calculate it:
Rule of thumb: Add 3/4 yard per cushion for self-piping if the cushion has piping on all edges. For a single throw pillow with piping on the perimeter only, add 1/4 yard.
For a box cushion piped on both top and bottom edges, the total piping length is: 2 x (2 x width + 2 x depth) = 4 x (width + depth). A 22" x 22" cushion needs 4 x 44" = 176" of piping — which fits within that 3/4 yard budget.
If you're sourcing piping cord separately, it's sold by the yard and costs $0.30–$1.00 per yard. The cord goes inside the bias fabric strip, so you need the same length of cord as your total piping length.