•   Sewing Machine
  • - Tape Measure
  • - Needles
  • - Pins
  • - Scissors
  • - Set Square
  • - Straight Edge
  •   Pencil
  • - Vanishing Marker
  • - Clamps
  • Step 2: Calculate the Curtain Dimensions


    For a pair of curtains the Finished Curtain Width for each curtain is half the pole length plus 5cm for ease.


    To calculate the Finished Curtain Length :

    • Decide where you will be attaching the curtain hooks on the curtain heading tape (there are usually 3 positions on pencil pleat tape).
    • Choose the position that will give you a Hook to Top distance nearest your measurement in Step 1, taking into account the curtain protrudes 0.5cm above the top of the heading tape.
    • Attach a hook to your heading tape and measure from the top of the attached hook to the top of the tape.

    The calculation for the finished curtain length is then.


    When deciding how full we want our curtains to be we talk in terms of Fullness Ratio. Fullness Ratio is the ratio of the width of the curtain before pleating to its finished width when pleated or gathered. The higher the fullness ratio the more gathered and heavier the curtains will be.

    We recommend a Fullness Ratio of 2.4 to 2.5 for a pencil pleat curtain. Note that some heading tapes come with a recommended fullness ratio suggested by the tape manufacturer.

    Questions & Comments


    Hi Cindy,

    I'm planning a pair of tweed floor length pencil pleat curtains to sit behind a box pelmet. They will be 235cm tall (pelmet 183cm wide, measured at max 44cm high to order fabric, but I may make it a bit shorter).

    You only mention 3" heading tape. My tape will be concealed behind the pelmet as I don't like the look of the tight gathers at the top.

    Is the use of 3" tape standard for all lengths and weights of curtain? If I was using buckram I'd go for a deeper one (say 5"), and I was wondering whether there's any advantage to using a 6" pencil pleat tape or whether this will be too much?

    Also, the tapes specify 2.5x fullness. I'm assuming if I only want 2.25x fullness I just don't pull the gathers up as much?

    Thanks for your help.



    Hi Emma

    Thank you for your question. There are many depths of gathering tape available but 3 inch is the most common for pencil pleat header and hence why we used it in the tutorial. There is no right or wrong with which one to use, it boils down to personal choice and design decision.

    As your gathers will be hidden, then I do not see an issue with either 3 inch or 5 inch tape, the pleats will look the same regardless. A deeper tape isn’t necessarily needed for heavier curtains - I have made long, heavy interlined with 1 inch tape to achieve a ruffle header.

    For a tape header curtain to have optimum fullness and look it’s best, I recommend 2 x fullness. If you choose less then your curtain will not look as full so you will have less fabric to gather in order to achieve the correct width. As you say, you don’t gather it up as much.

    If you decide to hand pleat, you could go with a 2.2 - 2.4 x fullness double pleat. A hand pleated curtain will always give a tidier stack back and pleat arrangement. You will not see your pleats but the curtain will look top notch!

    Good luck with your project. Cindy


    i'm making sill length pencil pleat curtains for a customer and they are asking for interlining. Do you think it will be too bulky? would you use DB1 lining for these?


    When I make sill length curtains with interlining, I use a light sarille. I always inform the customer that they may splay out slightly at the bottom when pushed tightly back but if allowed to hang naturally and with “training”, they will look good. One factor to consider, however, is the bulk of the face fabric. Linens and cottons shouldn’t be a problem but bulky weaves may make the curtains chunkier.

    Ultimately, this is a personal decision by your customer and your role to offer advice and explain any limitations. Cindy


    Me again!

    With regards to the scenario given in my post below in a recent message, the fabric I am using has a vertical stripe, that repeats ever 34.5 cm. . IF it is better to have a narrower-than-half a width section on the outside edge of each curtain so fullness does not exceed 2.5, (see post below) then I think I must have to match the stripes on each outside strip; this would mean one strip would end up having 2 raw edges. Does that matter?


    You always join selvedge to selvedge, (join the width then cut down after joining - as you don't know how much width you will lose on the joins). Great questions we will update the tutorial accordingly.


    Hello. Thanks for this website. I have followed you instructions for my 2 small windows.

    One needs window needs 2.7 widths; the other 1.7 widths.

    When you round this up to three widths and two widths, the fullness ratio ratio exceeds you max of 2.5. As they are smallish windows I want them to pull back well so they are not too bulky at the sides but I don't want them to look skimpy either when they are pulled.

    Your instructions only seem to mention cutting half widths and sewing those so they are on the outside of the as you look at the window. However, if this will make the fullness too great should I cut two smaller slices off the extra drop, for example if I need 2.7 widths, could I cut off seven-tenths of a width (@96cm, half that and sew a 48-50cm width to the outside edge to give optimum fullness or will this be fraught with difficulty and not the done thing?

    I have decided not to do any move beyond the cutting the drop stage until I can get my head around this.

    Thank you in advance for any advice you can offer.


    Yes cut them down to the correct width, so the fullness ratio doesn't exceed 2.5.


    Hi there,

    Thank you for the brilliant tutorials!

    I’ve made a pair of curtains following your instructions and they look lovely. However when I hang the curtains they were 1.5cm shorter than my desired length (220.5cm). During the measuring and making the fabric and lining panels everything looked ok. I didn’t use iron during the making.

    I’ve double checked my hook drop and hook to top measurements and they are correct.

    Do you have any idea why this happened?

    Is there a possibility when the curtain panels are made from a heavy fabric and are hanged on pole/track, the fabric to stretch and drop a few cm more than the finished curtain length?

    Thank you in advance!


    A measurement when making the curtain or measuring the window must be wrong.



    These tutorials have made it possible to have a go at making my first ever curtains! (though I wish I hadn't chosen pattern fabric which happened to have a half drop:)

    My pole is 137cm wide and the fabric is said to be 137 cm width , although it is actually 142 including the selvedges of 1.5cm each side. At what point do i need to trim the width or can I just leave it until later in the making?

    Many thanks.


    We wouldn't trim the width for a selvedge that size. It is only when you get exceptionally wide blank selvedges that we consider trimming them down.


    Thank you for your help. It's going very well.

    Regards Anne



    Thank you for your tutorials. They are brilliant.

    I'm planning to make a pair of sill length pencil pleat curtains.

    Do you recommend leaving the curtains a certain measurement above the sill to avoid touching?

    Also if the rail to sill measurement is not completely even across the width, how would you deal with this error?



    Hi this is covered in the video in the previous STEP (it's at the end of the video).  We go down to the sill and if there is a discrepancy across the width go for the longer length so there is no gap. The other option is to take the curtain below the sill ( about 15cm usually)


    I have a curtain pole Severn foot long, could you please advise me what width of curtains I would need for pencil pleat curtains to fit my pole?

    I've just moved to a new house and I'm not sure how to measure for these as I previously had blinds.

    Thank you for any help you can offer, I'll be most grateful.


    We do not make calculations for people but will answer questions on the written instructions.

    The way to calculate the width of curtains is written above. For a pair of curtains each curtain when made will be half the pole length plus 5cm wide. The number of widths of fabric you will need to make each curtain is covered in the next step of the tutorial STEP 3.


    I have been asked to take up some pencil pleat curtains that were too long so have removed the heading tape. The curtains were hung from the third channel on the tape and the drop measurement from the eye of the ring for the pole is 217 cm , do I then add the measurement from the top of the third channel and add that and 0.5cm to get my finished drop ? I have asked so many people and have come up with lots of answers none of which are the same and am now getting worried as want to do so a nice job !!!



    In our method you measure the hook drop (the drop measurement from the eye of the ring). Then put a hook in the row you are going to use on your heading tape and measure up to the top of the tape. Add these 2 figures together then add 0.5cm to take in to account the fabric that will be above the tape. That will give you your finished curtain length.


    Would you recommend using more than 2.5 ratio for pencil pleat curtains? I have enough fabric for around 2.7 ratio and wondered if it was worth using the extra fabric. The fabric is a slightly stiff cotton polyester mix so I wouldn't use the extra for cushions. Btw I love your tutorials! I've made 7 professional looking Roman blinds now, both lined and interlined. And although I've made plenty of curtains before, the last set I made following your instructions were the best. Best tip was not to iron the fabric which has saved me many a wobbly, stretched edge as I often use linen.


    We would stick with 2.5 in the workshop as there is only so much you can pull the tape.


    I'm looking to make pencil pleat curtains with 5cm stand up/ frill top.

    For this am I right in thinking I take my hook drop and add 0.5cm for the tape and then the 5 cm on top



    To calculate the finished curtain length, you need to hook drop plus measurement from hook to top of tape plus 5cm (rather than the 0.5cm)

    For your fabric quantity calculation you will need an extra 5cm length per drop as the fabric folds over at the top and comes back down to join behind the tape. 

    Helen Johnstone

    Thank you for the reply!

    So if my hook drop is 235cm and I'm using the middle pocket of a 3" pencil tape then the measurement from the middle where my hook will be to the top of the tape is 3.5cm.

    So... 235+3.5cm+5cm = finished drop

    Adding extra for cut drop for hems etc as you mentioned


    Ok much of this is covered in the next STEP.


    FINISHED CURTAIN LENGTH = hook drop (235cm) + hook to top of tape (3.5cm) + 5cm above tape.


    PLAIN FABRIC CUT DROP = FINSHED CURTAIN LENGTH + Hem allowance (16 or 20cm) + Heading allowance ( 5cm normal allowance + 5cm extra for fabric down back in this case)


    PLAIN FABRIC CUT DROP = 243.5 + 20 + 10 


    I am wanting to make curtains out of heavy wool tweed. Would it still be a 2.25 ratio for pencil pleat curtains?



    Sarah Brown

    I have some left over fabric and am going to make some curtains. I have a drop of 150cm and have cut 3 lengths of 174cm. The 4th length is 163cm only. I really would like to use 4 lengths. What would you suggest my turnovers should be?


    You could probably get away with 3cm at the top if you tack it down first, that would leave 10cm for your hem ( a double 5cm) or a smaller first turn followed by a longer second (but you would have to work out the position of the weights).

    Barbara Cole

    My dining room window is 244cm wide and my fabric is 136cm wide. If I use 2.5 widths in each curtain it gives me 2.7 fullness and 2 widths in each curtain gives me 2.1 fullness.

    Also another window in the same room is 142cm wide. In this window 1.5 widths in each curtain gives 2.8 fullness and 1 width in each curtain gives 1.8 fullness.

    Would you please advise me how many widths I should opt for. I am thinking that I could cut the half widths down a little so that I keep within the 2.5 fullness ratio.


    2.1 fullness ratio will not be quite enough.

    Yes we would cut down the outer panels to make a Fullnness ratio of 2.5 of both curtains. 

    Jane Wells


    Curtain track 215

    Sight size/ cut size per drop 211

    Fabric patterned with 64 cm half drop

    Fabric width 142

    Pinch pleat heading .

    Just wondered how much fabric I will require with the half drop please.

    Jane Wells


    I'm afraid we don't make calculations for people. There is an article on the site explaining Half drop pattern repeats and how to calculate fabric quantities for them. The next STEP of the tutorial also deals with calculating fabric quantities.

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