Cascading Roman Blind Calculator


Number of Rod Pockets and their positioning

Roman Blind Fold Calculator (Cascading Blind)



(all rounded to nearest 0.1cm)



How to Calculate your Folds

  • Enter the following values in cms.
    • Finished Blind Drop
    • Headrail Allowance*
    • Bottom flap depth
    • Cascade section depth
  • Select a number of cascade sections
  • Press "Enter" to calculate
  • Varying the number of Cascade sections and the cascade increment will change the length of the blind in the up position and the top pleat size.
  • The ROD POCKET LAYOUT section below will produce a diagram showing the rod pocket positions

* Please see our BLOG item Headrail allowance explained for more information on headrail allowances.

The bottom flap can be varied in length to your design requirements or made the same size as the cascade increment .

Rod Pocket Layout

Bottom of blind to rod pocket
diagram indicative only - not to scale or propotion

Making your own Blind?

This blind calculator is designed to compliment our free tutorial instructions.

Extra Help & Comments

I would like to have a blind made 116cms drop and 208cms wide material is 137cms wide how much material do I need thankyou
Sew Helpful
Hi June

We do not make calculations for people. There are tutorials on the website that explain fully how to calculate your fabric amounts in STEP 3. There is also a Roman Blind Fabric Quantity calculator on the website.

If you are having the blind made though, it would be best to ask the maker how much fabric they require in case they do not make the blind the same way we do.
Jean Bates
This is a fabulous calculator. It has made me change my mind from having my roman blinds made professionally to making them myself. Can't wait to get started.
Jill G
Wonderful website, saved me hours of calculations! Thanks
Where do you sew on the rings? Top edge or middle or bottom edge of rod pocket.
Sew Helpful
STEP 9 of the roman blind tutorials show you how and where to sew on the rings.

Brilliant website. I have made one blind already which looks great. I now am trying to work out if I can make three separate blinds for a bay window. The lengths are different 230 X 2 and 1 X 270. Is it possible to adjust measurements so that all three have the same length when pulled up. Hope that makes sense. I am using a blind kit with 5 rods
Sew Helpful
I'm afraid we havent the time to go through the iterations to try and match up cascading blinds of different lengths.

The easiest way (not cascading) but with normal folds is to make the pleat sections 20cm (as 40cm is the difference between your blinds). Using a 10cm headrail allowance try using our standard blind calculator. One blind with 11 seactions and the other with 13.  Note you will need 6 rods in the longer blind and the blind will be 30cm high when pulled up.
Nicola Blackwell
Thank you for this calculation and your fantastic website!

Presumably I need to take of the hem allowance of the face fabric when pinning/marking out the rod pockets on the lining? The measurements that you have given are from the bottom of the actual blind and not the bottom of the lining I think? Thank you
Sew Helpful
Yes the positions of the rod pockets calculated are from the bottom of the blind.

The linings are not the same on lined and interlined blinds with their bottom at different positions on the blind. So the calculator tells you rod pocket positions from the bottom of the blind.

The tutorials on the website tell you how to make the lining up for which ever type of blind you are making. 
Nicola Blackwell
Thank you for your reply. It was as I thought. I always make interlined blinds as per your great instructions!
Oh my word ... this is absolutely fantastic!!!!!! I have just spent hours trying to get my head round making a cascade blind and in desperation turned to my computer ... and found this. Thank you soooooooooooooo much!
This calculator is very good BUT you need to have a blind cord stopper by law on the bottom lath.This takes up 2cms when pulled up. Your calculator does not have the option to put this in if you wish to follow this law. Could you help Sewhelpful?
Sew Helpful
I'm sorry we're not familiar with that law (is it in the USA?). Can you not just adjust your headrail allowance to make sure there is at least a 2cm gap between the rods and the headrail when pulled up?
Your calculator doesn't seem to be working, any idea when it will be back up again?
Sew Helpful
It is working when we try are you sure you are putting reasonable figure in. If you enter figures that wont work it will come up with an error message.

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