(Cascading Blind)



(all rounded to nearest 0.1cm)
Rod Pocket Layout
Bottom of blind to rod pocket
diagram indicative only - not to scale or propotion



How use this Calculator

  • 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 .

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.
If it’s a check turn it side ways no join !
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.
How do I calculate the amount of cord I will need..
Thank you in advance
Sew Helpful
Look at STEP 11 of our Roman blind tutorial and you will see where the cords travel. 
Hi, can I use this calculator if I only want one a casading at the base so to show contrasting base of blind? Thank you in advance
Sew Helpful
If you mean something like this where all the folds of the blind will line up, but the bottom flap will hang down lower when the blind is pullled up.

roman blind with bottom flap

Then Yes. 

You can do that if you put a value of 0 for the "Cascade Increment" and enter what ever you want the bottom flap to be longer as the "Bottom Flap Depth" value. 

hi there - this is really great! I have also purchased your video tutorials.
Quick question - when I use the calculator what is the allowance for rode pockets I do I need to add this myself? Also I am assuming that the the measurement is from the bottom of the blind and I do not need to deduct the 2cm hem allowance as per the video?
Many thanks
Sew Helpful
Hi Kate

This Calculator JUST calculates the position of the rod pockets relative to the bottom of the blind. It does not calculate lining quantities or how to mark the lining as this varies depending on whether  the blind is lined or interlined. The construction and making of the blind is covered in the tutorials.
Mary F-S
A great tool. It would be very helpful if there was some way of printing out the measurements and diagramwhen calculated so that they were to hand when making up the blind.
Elizabeth Parry
Pls do I add allowance to rod pockets? Or it's all built in calculations?
Sew Helpful
This calculator shows you the position of the pockets, it does not include any fabric allowance to make pockets as you may be using tape and the amount of fabric needed to form a rod pocket from the lining will vary depending on the thickness of your rods. See our tutorials on how to make the blind.
Penny E
I have made a cascading blind (157x100cms)using lining with bonded interlining and have followed your instructions/ video that have been great. It looks almost perfect but the lowest pleat interval seems bigger than it should. All the measurements appear to be correct. I used double stitch rod pockets and wondered if you had experience of them being less flexible in the lifting? or my batten depth is only an inch. Could this be interfering with an even lift. I have 2 more blinds to make so would like to sort this before I start. Thanks
Sew Helpful
Have you used enough headrail allowance. It sounds like your rings are hitting the batten before the blindis fully up.

See this blog item about headrail allowance. HEADRAIL ALLOWANCE EXPLAINED 
Penny E
Thank you for getting back to me. Yes, I used a 10 cm head-rail allowance. I didn't use rings, but threaded the cord through the ready made loops in the rod pockets (which I chose because I thought it would look neater from the rear and the lining fabric would be too bulky to make integral pockets). When I refer to them being less flexible, I suppose I mean less adaptable.When I checked behind (with the curtain lifted) it seemed to improve with some manual help.
Sew Helpful
I can't really say without looking at it (we dont use tape). Are the loops on the tape when you pull up, stretching out up away from the rod. If so this may account for the blind being a bit lower than expected. 
Would be great if I could print off the rod pocket layout with dimensions once Ive entered the details into the calculator, so I dont need to keep referring to the screen.
Sew Helpful
We'll look into that (wil require coding).

In the mean time the results and calculator fit nicely on to a smartphone. 
Shirley Williams
I ordered 3 cascade blinds for my bay window.the center line doesn't line up with my side windows ..
Sew Helpful
I'm afraid we dont comment on products made by companies.
Amanda Larsson
Hello, please could you help me, I've been playing around with the calculator but I still can't seem to get what I need.
I have a 180cm drop, I need the pulled up blind length to be near 30cm and it's is a cascade blind, I can't get the bottom flap to be in the cascade as well!?!?!
Hope I make sense! Thanking you in advance !
Sew Helpful
Set the bottom flap size to the same as the cascade size .
How do you make a false cascade roman blind?

Thank you
Sew Helpful
We haven’t got a tutorial for that yet.
Eleanor king
I am trying to make a cascade blind don’t understand your diagram my blind is 75” finished lenght and one inch for Velcro and three inches for wood to go in I don’t know the measurements for cascade don’t know what measurements to put in problem 5 or 6 rods to go in blind
amy jo
Hi I have made a cascading roman blind using your tutorials. However now that it is finished the length when in the 'up' position is too long I now realise - blocking out too much light. Is there a way I can alter this, by moving or adding the rods??
Sew Helpful
You will need to calculate new rod pocket positions so the blind is the desired length when pulled up, remake the lining on the back with the rod pockets in the correct positions and reattach the new lining to the blind. Quite alot of work.

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