Curtain fabric calculator
How much fabric curtains need at a given fullness.
Fill in the fields and the result will appear here automatically.
Estimates fabric for vertical drops using the full roll width. Track width × fullness is the total flat fabric width before gathering, not the finished curtain width. Both the drop count and each drop length affect consumption: a taller curtain needs more fabric at the same width.
How it works
Formula and logic
Flat width = track × fullness. Drops = flat width / fabric width, rounded up to a whole count. Cut length = height + total allowance; metres = drops × cut length / 100. Drop rounding uses decimal dimensions and preserves a real positive remainder.
Example
140 cm × 2 = 280 cm before gathering. A 280 cm roll needs one drop of 250 + 20 = 270 cm, or 2.7 m. A required flat width of 300 cm on that roll needs two drops.
Fields and units
- Track width — cm
- Fullness ratio — 1
- Fabric width — cm
- Finished height — cm
- Top and bottom allowance — cm
How to use
- — Enter the track width and your chosen fullness; the heading and project determine it, with no universal ratio.
- — Enter the usable fabric width for this cutting plan. Side hems and seams are not deducted separately.
- — Enter the finished height and the combined top-plus-bottom allowance in centimetres; zero allowance is allowed.
- — Check pattern matching, shrinkage and railroading separately; the model does not add them automatically.
Method and limitations
- Calculation method
- Formula and logic
- Limitation
- A full-width vertical-drop estimate, not a finished cutting layout. Side seams, pattern repeats, shrinkage and supplier restrictions need separate checks.
FAQ
Which fullness should I choose?
Choose fullness for the fabric and heading. A ratio of 2 means twice the track width in flat fabric; it is not a universal pleat rule. Whole drop counts make fabric consumption increase in steps.
Why round drops up?
This model takes each drop at the full fabric width. A remaining partial width requires another cut; seaming and alternative layouts are possible but are not optimised here.
Should I allow for the pattern repeat?
There is no separate repeat field. Work out the added length from the actual pattern and matching plan; half a metre is not a universal maximum.
Which fabric width is more economical?
Compare the drop count, cut length and price per running metre. Railroading changes the plan and is not suitable for every fabric; this formula uses vertical drops.