The size of a blind for 34 inch window will depend on the mounting place, i.e., it will be different for inside and outside mounts.
Blind Size for Inside Mount
For a 34 inch window, you need to look for blinds that are slightly narrower than the width of the window for an inside mount. Deductions will allow the blinds to fit properly and cover the window opening without obstructing any part of the window frame.
You can find window blinds online at AffordableBlinds.com in 1/2 inch increments, so you should consider a 33 1/2 inch or a 33 inch blind for your 34 inch window. It is also a good idea to carefully measure your window frame at three places – the top, middle, and bottom – to ensure that you get the right size blind for your needs.
Note: You should provide the dealer with exact measurements of the window frame and ask them to make the deductions themselves.
Blind Size for Outside Mount
For an outside mount, the size of the blinds will be greater than the width and length of the window frame. In other words, you need to add a few inches to the length and width. This addition will improve the functional potential of your window treatment.