The practical toolbox
Curtain width & panel calculator
Calculate how many curtain panels and packs you need from your pole or track width. Compare flat and gathered curtains, balanced pairs and your chosen fullness.
Save this version with its URL. Bookmark this page or copy its link to reopen your inputs later. Save a new link after making changes. Anyone with the link can read your inputs. Results are recalculated on reopening; print a copy if you need a fixed record.
Create a saved link with AI
Give your AI assistant your measurements or figures and the instructions below. It can create a ready-to-open link for this curtain panel width calculator. Open the link, check the inputs, then bookmark it or copy the URL to reuse it later.
Copy this prompt and add your information:
Read https://www.lejnel.com/curtain-width-url-guide.txt and generate a clickable saved-plan URL for my curtain panel width calculator. Convert my units to the guide’s required units. Ask for missing inputs instead of guessing, and explain any assumptions. Return the link and a summary of the inputs used.
Read the URL format and examples · AI instructions for all tools
The URL contains your inputs. Anyone with the link can read them. Future calculator updates may change results; retain a printed copy when you need a fixed record.
What to buy
How many curtain panels do I need?
To estimate curtain panels, multiply the width you want to cover by your chosen fullness, then divide by the flat width of one finished curtain panel. Round up to whole panels. For curtains on both sides, round up each half separately to keep the two sides equal.
How to measure curtain width
- Measure the pole or track span your closed curtains need to cover. Window glass width alone may leave out the area beside the window.
- Find the finished flat width of one panel on its label. Check whether a listed width refers to one curtain or the whole pair.
- Choose the fullness specified for your curtain heading. For example, 2× means twice as much flat fabric as covered width; it is not a universal recommendation.
- Choose one group or equal groups on both sides, then enter the number of panels supplied per pack.
- Review the panel count, packs to buy and resulting fullness. Use the flat and folded views to compare the fabric width with the covered span.
Curtain width formula
Multiply the covered track width by your chosen fullness. Divide by one panel’s usable flat width and round up. For a balanced pair, calculate each half separately so both sides contain the same number of panels. Round that count up again to whole retail packs.
Curtain panel examples
These examples all use a 2,000 mm covered width and an illustrative target fullness of 2×. Pack sizes and panel widths are examples, not product specifications.
| Flat panel width | Arrangement | Panels to hang | Packs of 2 | Actual fullness |
|---|---|---|---|---|
| 1,400 mm | One group | 3 | 2 | 2.1× |
| 1,400 mm | Both sides | 4 (2 per side) | 2 | 2.8× |
| 2,000 mm | Both sides | 2 (1 per side) | 1 | 2× |
Worked example
A 2,000 mm track at an illustrative fullness of 2 needs 4,000 mm of flat fabric. With 1,400 mm panels, a single group needs three panels. A balanced pair needs two panels on each side: four total. Packs of two therefore require two packs. These figures explain the arithmetic, not a recommended fullness.
Why can a pair need more panels?
Each side must meet half the target width with a whole number of panels. Three panels cannot be divided into equal whole-panel groups.
Does a pack of two mean two panels per side?
No. A two-panel pack contains two panels total. Check the listing and enter its actual pack count.
Is curtain width the same as window width?
Not necessarily. Use the span your curtains must cover along the pole or track. This calculator does not add an automatic extension beyond the window: measure your actual setup and follow its instructions.
What is curtain fullness?
Fullness is flat fabric width divided by covered width. At 1×, the fabric lies flat; a higher value leaves more fabric for folds. The resulting fullness may exceed your target because the calculator rounds up to whole panels.
Can I enter feet or inches?
Yes. Select Imperial above the calculator to enter inches. Metric uses millimetres. Switching units preserves the physical measurements, and saved links store dimensions in millimetres.
Can I save my curtain measurements?
Use Copy estimate link or bookmark the complete saved URL to reopen the inputs. Print the estimate for a fixed record, including your measurements, quantities and diagrams.
Does this calculate fabric to sew?
No. Use finished usable panel widths. Raw fabric, seams, hems, pattern repeats and cutting losses need a separate sewing plan.
What about length and stacked curtains?
This tool does not calculate drop, floor clearance, stack-back, overlap, returns, hardware loads or installation positions. Include any additional coverage in your measured span only when the manufacturer’s instructions require it. The drawing is schematic and does not show real pleats.
Assumptions and limitations
All panels have the same usable width and heading. Multiple panels on one side may remain separate; check whether your intended product can be used this way. Rounded-up panel widths can give more fullness than requested. Pack spares are excluded from the hanging arrangement. Check dimensions, appearance, compatibility and order quantities yourself before buying. This estimate is provided without a guarantee and is not an installation specification. Printed diagrams are not full-size templates.
Also planning the room? Try the gallery wall planner or paint calculator.