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7 Tips for Accurate Measurements

The measuring tape is arguably the most dangerous tool in your bag. You can hurt yourself with it and not even know it – until later when you start to bleed – green not red.

I’ve been “the blinds guy” since about 1980 – guess that makes me “the old blinds guy” by now. I have formed some rather strong opinions about the right and wrong ways for doing things.

Here is my list of best practices for measuring for window blinds…

  • Measure Every Window

If you want a professional installation, you must start by measuring like a professional. Dimensions can vary by several inches from window to window even though they may all appear to be the same size. Always measure every window!

  • Use the Right Measuring Tool

A tape with a wide blade (1″ or more) is easy to work with because it is rigid enough to span the window without bending or kinking and it can stand up on it’s own for an easy vertical measurement. If you have trouble reading the divisions on a tape, watch this video – just remember – he’s a carpenter and measures everything to the nearest 1/16″. When you are measuring for blinds you don’t need to be that precise. In the window covering industry, the standard is to measure to the nearest 1/8″. Most fabricators won’t accept measurements that contain 16ths or 32nds of an inch.


If you are still having trouble, you might want to consider a laser measuring tool with a digital readout. I’m pretty old-school and I still use my metal tape most of the time. But, under certain circumstances, my laser measurer allows me to easily do things that I wouldn’t be able to do with a metal tape, at least not without a helper. A laser measure is easy to work with and very accurate.

  • Choose Your Window Treatment Before You Measure

Each type of window covering has it’s own unique set of measuring requirements. None of it is rocket science, but you can’t know what to do or what to look out for if you haven’t decided which type of blind or shade you want to buy. Select the type of product that you want before you measure.

  • Check Each Dimension in (at least) 3 Places

Window opening dimensions often vary from side to side and top to bottom within the same window. As the installer, it is your job to identify the largest and smallest dimension in each direction. Depending upon your choice of blind or shade you will need this information to make an informed decision about which dimensions you should use when ordering.

  • Be Consistent When You Write Down Your Measurements – (part 1)

It is the standard in the industry to record window covering dimensions as w x h (width by height). If you are such a rebel that you just can’t conform to this standard, be sure to label your dimensions so you’ll remember which is which when it comes time to place your order (if you reverse the dimensions you will end up with a blind that fits just fine as long as you mount it sideways – don’t laugh, it happens all the time).

  • Be Consistent When You Write Down Your Measurements – (part 2)

If you are measuring for more than one or two blinds, use a measurement worksheet and label each window. When measuring a room with more than one window, go around the room in a clockwise direction (or do whatever works for you, the main thing is to be consistent). Label each window as you go around the room. For example, in the dining room you might label them as “diningRm1”, “diningRm2”, etc. Keep your worksheet where you can find it so you can use it as a reference to lay out the job for installation.

  • Do a Reality Check

Be sure to scan the completed worksheet for dimensions that seem out of place. For instance, if all of the windows in the breakfast nook measure out at approximately 36″ x 48″ except for one oddball at 36″ x 45″, you would probably want to check your work again.