• - Fabric
  • - Lining
  • - Thread
  • - Heading Tape
  • - Weights
  • - Curtain Hooks
  • Tools
  • - Sewing Machine
  • - Needles
  • - Pins
  • - Clamps
  • - Scissors
  • - Set Square
  • - Straight Edge
  • - Invisible Marker
  • - Tape Measure
  • Step 2: Calculate the Curtain Dimensions
    Printable Worksheet
    Printable Worksheet


    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.

    Your Questions & Comments



    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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