Fabric calculator
Enter the cut size of each piece, how many you need and the fabric width. The calculator fits as many pieces as possible across the width, tries them both ways round and gives the length to buy with an allowance for shrinkage and straightening.
Pieces
Fabric
About the fabric calculator
Enter the cut size of each piece, how many you need and the fabric width. The calculator fits as many pieces as possible across the width, tries them both ways round and gives the length to buy with an allowance for shrinkage and straightening.
Part of SmartCalcy’s crafts & sewing tools. It runs in your browser with no account, uses your own currency and units (change them at the top of the page), and gives estimates for information only, so check official guidance before you rely on a result.
How to use the fabric calculator
What it calculates and when to use it
Works out how much fabric to buy for a set of rectangular pieces, trying them both ways round to find the layout that uses the least length.
How to use it, step by step
- Enter the cut size of each piece, including seam allowances.
- Enter how many pieces you need.
- Enter the usable fabric width and an extra allowance.
- Read the length to buy and the layout.
What each input means
- Piece width and length – Starts at 45 × 60 cm.
- Number of pieces – Starts at 6.
- Pieces can be turned – Untick for nap or one-way prints.
- Usable width – Starts at 112 cm.
- Extra – Starts at 10% for shrinkage.
How to read the results
- Fabric to buy – Rounded up to the next 12.5 cm or ⅛ yard.
- Layouts compared – Pieces across, rows and length for each orientation.
The formula
Pieces across = floor(fabric width ÷ piece width). Rows = ceil(pieces ÷ across). Length = rows × piece length × (1 + extra).
A worked example
With the starting entries: 2 pieces of 45 cm fit across 112 cm, so 6 pieces need 3 rows × 60 cm = 180 cm; with 10% extra 198 cm, rounded up to 2 m.
Assumptions and limits
- Pieces are rectangles cut in straight rows.
- Pattern matching is not included.
Common mistakes
- Using finished sizes instead of cut sizes.
- Using the width on the bolt rather than the usable width between selvedges.
Frequently asked questions
How do I convert metres to yards?
Divide by 0.9144. Switch to US units to see yards directly.
Should I pre-wash fabric?
For washable items, yes. Allow extra length for shrinkage.
Related tools
Layouts compared
| Layout | Across | Rows | Length |
|---|---|---|---|
| As entered | 2 | 3 | 180 cm |
| Turned 90° | 1 | 6 | 270 cm |
- Length before extra
- 180 cm
- With extra
- 198 cm
- Rounded up to
- the next 12.5 cm