CraftM8 › QuiltM8 › Calculators › Backing
How much backing?
Panels, seam direction and yardage for a quilt back — including what the other seam direction would cost, and what changes on 108″ wide backing. Overhang is per side, the way longarmers ask for it.
Backing width: 68" · Backing height: 80" · Seams: 1 seam · The other way: Horizontal seam · Panels the other way: 3 panels · Fabric used: 160" · Batting width: 68" · Batting height: 80"
Show the maths
| 1 | Backing size — 60" + 2 × 4" by 72" + 2 × 4" | 68" × 80" |
| 2 | Panels — 68" across, joined panels of 40" less 1/2" seams | 2 |
| 3 | Fabric used — 2 × 80" | 160" |
| 4 | Fabric to buy — 160" → round up to the next 1/8 yd | 4 1/2 yd |
| 5 | The other direction — seams the other way (3 panels) | 5 3/4 yd |
Backing includes the overhang all round. Allow for shrinkage if the fabric has not been prewashed.
Where the formula comes from
The backing must cover the quilt plus overhang on every side. Panels come from the usable width of fabric; the tool prices both seam directions and reports the better one, because the difference is frequently more than a yard.
- Pieced backing panels. Panels joined edge to edge lose two seam allowances per seam, so n panels span n × usable width − (n − 1) × 2 × seam allowance.
- Longarm overhang. Longarm quilters commonly require 4" of backing beyond the quilt top on every side; 2" is the domestic-machine minimum.
This is the app's own arithmetic running in your browser, put through the same worked examples every time this site is built.
A worked example
The worked example is the how-to quilt after its borders: 66″ × 78″ with 4″ overhang. Change the fabric width to 108″ and the same quilt needs one panel and 2 1/8 yd.
| 1 | Backing size — 66" + 2 × 4" by 78" + 2 × 4" | 74" × 86" |
| 2 | Panels — 74" across, joined panels of 40" less 1/2" seams | 2 |
| 3 | Fabric used — 2 × 86" | 172" |
| 4 | Fabric to buy — 172" → round up to the next 1/8 yd | 4 7/8 yd |
| 5 | The other direction — seams the other way (3 panels) | 6 1/4 yd |
Works with
- How much binding? — Same finished size, next question.
- How wide do I cut the borders? — Borders change the size the backing must cover.
In the app, this answer joins a quilt
Save it to a project, add the other tools' answers, and the shopping list totals every fabric with one rounding — then prints a cut sheet for the table. Offline, no account, one payment, yours forever.
In development A closed test on Google Play is the next step.