Quilt Backing Calculator
Plan pieced backing panels and compare two fabric orientations with explicit margins and seam allowance.
YOUR CALCULATION
Result
—
Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Add the backing extension to both sides of each quilt dimension. Count panels allowing two seam allowances at each join. Multiply panels by their required cut length. Compare the two allowed orientations and entered price.
Covered width=n×fabric width−2×seam allowance×(n−1)
Worked example
A 60 by 80 inch quilt, 4 inch extensions, 42 inch fabric and half-inch seams needs two 88 inch panels in the lengthwise orientation.
Assumptions and input details
Straight seams, usable width and no shrinkage are assumed. Rotation is allowed only when selected. Print matching, directional motifs, grain restrictions, washing loss and extra trimming are not inferred.
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Choose from 23 length definitions, including explicitly labelled regional measures. Area conversions square the length factor; geometric volumes cube it.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
Plan full-width straight-grain binding strips with a stated 45-degree join loss and an entered closing allowance.
Plan identical rectangular fabric pieces with seam allowances, shrinkage, selvages and optional 90-degree rotation.
Convert gsm and ounces per square yard while keeping areal mass separate from linear-yard weight.
Reserved advertising space.