How to Calculate Curtain Fabric Quantity
- Enter your pole or track length
- Enter the finished length of your curtain.
- Enter the width of your fabric.
- Enter the vertical pattern repeat of your fabric, (enter 0 for a plain fabric - see info button regarding half drop pattern repeats)
- Select whether your curtains are to be just LINED or INTERLINED as well
- Select whether calculating for a SINGLE curtain or a PAIR.
- Select your curtain heading type, either pencil pleat, double (pinch) pleat, triple pleat, goblet pleat or cartridge pleat.
- Enter the depth of your buckram ( enter 0 for pencil pleat heading as you will be using tape)
- Enter a desired fullness ratio (see info button for recommendations and our tutorials STEP 3 for more info)
- Decide whether you want to round down the number of widths (see info button and see calculator assumptions note 3 - calculator automatically rounds up if not selected )
- If you have a patterned fabric decide if you want to inclue an extra pattern repeat to position the pattern on the curtain (see info button for more details and what to do with half drop pattern repeats)
- Press Calculate
Note if you change any entries press calculate again to re-calculate.
- Curtains 1.5m or shorter have a fabric double 8cm hem, lining double 6cm hem.
- Curtains over 1.5m in length have a fabric double 10cm hem, lining double 8cm hem.
- Calculator defaults to rounding the number of fabric widths UP to the nearest whole number. If the resultant Actual fullness ratio is too high select the option to round DOWN to the nearest whole number and re-calculate. Then check if this lower Actual fullness ratio is more suitable.
- 5cm trimming allowance on lining cut drops
- 10cm trimming allowance on interlining cut drops
- 5cm trimming allowance on plain fabric cut drops (note not included for pattern fabrics as adjusted cut drops are usually longer than required)
- Results are rounded up to nearest 10cm (0.1m)
- Lining and interlining is assumed to be a similar width to the fabric.
This curtain fabric calculator is based on making curtains using the heading and hem allowances in our online tutorials. Full written explainations of the calculations the calculator is based on are given in the tutorials on this website.NOTE: Our goal is to make the Fabric Calculator as accurate and helpful as possible, but please double-check all results thoroughly. (see terms).
Making your own curtains?
Find full FREE written instructions and your questions answered here in our online tutorials.
Extra Help & Comments
Whether you decide to cut the fabric down to the lining or add more lining will depend on how that will affect your fullness ratio, which will make it nearer the ideal and nearer your ideal pleat size and spacing.
What figures are you putting in to think it is adding an extra pattern repeat.
You are doing what we would do but you are not making the same calculation as the calculator which is making the strict calculation (it doesn't look at reducing allowances to save fabric). That is really for people who know how to make their own calculations and can make judgements to adjust allowances if there is a lot of fabric to be saved.
What the calculator is doing is
Cut drop = Curtain length + Heading allowance + Hem allowance + (no trimming allowance as pattern fabric)
= 272 + 15 +20 = 307cm
The adjusted cut drop is cut drop divided by pattern repeat, then that answer rounded up to the next whole pattern repeat.
= 307 / 34 = 9.02 (strictly rounding up = 10)
therefore adjusted cut drop = 10 x 34 = 340cm
Now in reality we would look at that and think another pattern repeat for the sake of 1cm is not worth the extra cost of all the fabric that would be needed as there are 7 drops. (7 x 34 = 2.38m of extra fabric) so we would say lets reduce the inner fold on the hem by 1cm and that will give us a cut drop of 306cm, that is exactly 9 pattern repeats so the adjusted cut drop is now
9 x 34 = 306cm
The information to make these judgements is there in the answers of the calculator, Eg Cut drop, Adjusted Cut Drop, Heading, Hem and Trimming Allowances. It is a judgement you as the maker have to make though and is what you have done in your calculation. So in summary the calculator is strictly right, but we would have done it the same way as you and gone for an ACD of 306cm instead of 340cm to save a lot of fabric.
Note you can get caught out doing this sometimes when the actual pattern repeat when you measure it on the fabric comes out a bit longer than that given by the manufacturer.