# Quilt Calculator

Calculate fabric yardage for quilt blocks, sashing, borders, and backing. Enter quilt size and block dimensions to get a complete cutting plan.

## What this calculates

Planning a quilt? Enter your finished quilt size, block dimensions, sashing, and border widths to see exactly how many blocks you need and how much fabric to buy for every part of the quilt top and backing.

## Inputs

- **Finished Quilt Width** (inches) — min 10, max 200
- **Finished Quilt Length** (inches) — min 10, max 200
- **Finished Block Size** (inches) — min 1, max 36 — Size of each quilt block after sewing
- **Seam Allowance** (inches) — min 0, max 1 — Standard quilting seam allowance is 1/4 inch
- **Sashing Width** (inches) — min 0, max 6 — Strips between blocks. Enter 0 for no sashing.
- **Border Width** (inches) — min 0, max 12 — Width of the border around the quilt
- **Fabric Bolt Width** — options: 42 inches (usable from 44-45" bolt), 54 inches, 60 inches — 42 inches usable is standard for quilting cotton (44-45 inch bolt minus selvages)

## Outputs

- **Blocks Across**
- **Blocks Down**
- **Total Blocks**
- **Block Fabric Needed**
- **Sashing Fabric Needed**
- **Border Fabric Needed**
- **Backing Fabric Needed** — Based on quilt size plus 4-inch overhang
- **Total Top Fabric**

## Details

How the calculation works:

  - Blocks: The calculator figures out how many blocks fit across and down after subtracting the border. Seam allowances are added to each block for cutting.

  - Sashing: If you add sashing (strips between blocks), the calculator accounts for horizontal and vertical strips and calculates fabric separately.

  - Border: Four strips cut to the quilt's finished dimensions, with seam allowances.

  - Backing: The quilt's dimensions plus 4 inches of overhang per side for quilting. If the quilt is wider than the fabric bolt, multiple panels are calculated.

Standard quilt sizes:

  - Baby: 36" x 52"

  - Throw: 50" x 65"

  - Twin: 68" x 90"

  - Full/Double: 80" x 90"

  - Queen: 88" x 96"

  - King: 104" x 96"

Fabric tips:

  - Always buy 10-15% extra to account for cutting mistakes and shrinkage

  - Pre-wash quilting cotton before cutting -- it typically shrinks 3-5%

  - Standard quilting cotton bolts are 44-45 inches, but you only get about 42 inches of usable width after removing selvages

## Frequently Asked Questions

**Q: Why does the calculator use 42 inches instead of 45?**

A: Quilting cotton bolts are typically 44-45 inches wide, but the woven edges (selvages) are unusable. After removing selvages and accounting for slight variation, 42 inches of usable width is the standard quilting estimate.

**Q: How much extra fabric should I buy?**

A: Buy 10-15% more than the calculator shows. This covers cutting errors, fabric shrinkage, and slight pattern matching needs. If you are a beginner, 20% extra gives you a comfortable margin. It is always better to have leftover fabric than to run short mid-project.

**Q: What size blocks should I use?**

A: 12-inch finished blocks are the most common and have the widest selection of free patterns. 10-inch and 6-inch blocks are also popular. Smaller blocks create more intricate designs but require more piecing. Larger blocks go together faster but offer fewer layout options.

**Q: Do I need sashing between my blocks?**

A: Sashing is optional. It adds visual separation between blocks and can make complex blocks easier to see. It also makes the quilt slightly larger without adding more blocks. Typical sashing is 1.5 to 3 inches wide.

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Source: https://vastcalc.com/calculators/everyday/quilt
Category: Everyday Life
Last updated: 2026-04-08