What type of window? What is the window made of? New Construction or Replacement? What brand window? All of these questions need to be answered before anyone can even think of answering your question, even then it may not be possible as I am not aware of a formula for this.

What does "nominal" mean? If you ordered the window to that size, not a window for that size of opening, you should be able to devise a formula for your particular window based on what material, and dimensions of it, the shop uses, and whether the panes are fixed or opening.

But I still wouldn't order a screen or curtain rod cut to size until I have the window in hand, especially if it's wood. Maybe other materials are more exact, but the exact placement of a saw blade can make a bit of a difference... which is why tolerances are factored in!

Karin L

So you usually talk about the "rough opening" dimensions that a window fits in. Or the "unobstructed glass" for the part that you get to look through. The actual dimensions of the window are somewhere in between :-) .

But it sounds like you are looking for the width from the outside of the interior trim? And the height from the bottom of the trim to the top?

I'm sorry - I obviously did not word my question precisely enough.

To give some background, we are putting a new window in an existing exterior wall for a back-to-studs kitchen remodel. We need to order custom-sized upper cabinets weeks in advance, and we don't want to live with no kitchen any longer than we have to, so the cabinet dimensions must be finalized before the window is installed. We will have some filler to play with on one side of the cabinet runs, and we will obviously not bring the cabinets flush to the edge of the window, but we need to be in the right ball park to within about 1/2".

dennisgli asked: "But it sounds like you are looking for the width from the outside of the interior trim? And the height from the bottom of the trim to the top?"

That's exactly what I want to know. I don't care about the glass area, or the opening when the window is open; all I want to know is the width inside the trim. In other words, if the windows is described as 48" wide and the trim is 1/2" thick is it as simple as 48" - (2 * 1/2") = 47", or are there other components that reduce the distance further?

karinl asked "What does "nominal" mean?"

Let me give you an example. I just measured a window elsewhere in the house. This particular window is trimmed with drywall (the drywall wraps around from the wall into the space where the window is, and butts directly onto the metal frame of the window). I measured the opening in the wall from one side to the other; the result was 46.25".

I'm sure that window was sold as a "4 feet wide window". I would use the term "nominal" to describe that because the overall width of the widow including the flange would have been more than four feet and the finished width of the opening in the wall is less than four feet.

The above example is what made me ask the question - the drywall is only 1/2" each side, the window is nominally 4' wide, so where did the other 3/4" go to?

Virtually every manufacturer's 60" window is going to be sized differently. Your first step is to determine the brand or manufacturer you want.If you are going to use the same manufacturer of the windows in your home, you have your answer: 58.25 or 1.75 under "nominal".

Sorry - I've never heard of anyone measuring windows the way you describe.

we are putting a new window in an existing exterior wall

So what are the spec's (dimensions) for the new window? What manufacturer/model? From there we should be able to start to answer your question.

Windows are always called out on blueprints in feet and inches so if it looks like it says 60 you should look very closely to verify because it could easily be 6' 0" OR 60"
The cost of these mistakes is usually really high in framing.
One GC I framed for made an unforgivable mistake (from my perspective) of putting the _unit size_ on the drawings instead of the R/O's. He expected me to know to look in the Andersen catalog and find the unit and then discern the R/O from the table. We had to reframe a whole house full of windows (at my own cost) because of that one.\
Casey

"nominal 60" wide window"

There is no such thing.

I was really asking, what does "nominal" mean to you, and I don't think you are going to get that answer from looking at your existing windows because you (probably) don't know what the ordered size was. When we order wood windows we give the shop the exact measurements we want the box to be. If it's any other material, if will be more complicated.

So again, key information is what the material is, and how the shop is going to implement that 60" dimension.

But for what it's worth, I would try not to do what you're doing - order cabinets with a 1/2" room for error in advance of installing the window. The reason is the little surprises that the house may have in terms of say, whether the opening is square, whether the framing studs are perfectly upright... and there may be other traps I haven't run into yet. This is a potential error that could cost you the entire cost of a replacement cabinet if you have no room to correct a 1/4 inch mistake. Can you order the upper cabs separately later, get the lowers in process already?

But if you are determined to do that, you should have a very detailed discussion with your window manufacturer so you understand how the window is to be constructed, measured, and installed. And invest in a good level, and hope your window is perfectly square too :-). Or ask your cabinet shop if they can leave the final length determination as late as possible.

Karin L

"So again, key information is what the material is, and how the shop is going to implement that 60" [inch] dimension. "

WHAT is the "60" dimension"?

Glass?
Finished opening?
Rough opening?
Space between the cabinets?
Is trim going to be used around the window?

Windows are built to fit the application.

Tell them what you what and they can tel you what they have that might match your needs.

They will ask you questions to find out what they need to know.

I said: "nominal 60" wide window"

Brickeyee said: "There is no such thing."

"Nominal" is an English word; I used it perfectly correctly as such. To give an example, 2 x 4 is a nominal size.

Anyhow, despite everyone's best efforts, I think I know what I need to know to move forward.

Brick was accurately stating that in the world of window nomenclature, your "nominal" term means nothing. Even the example you used about 2x4's is inaccurate.
A true statement about 2x4's using "nominal" would be: Nominal 2x4's actually measure 1.5" x 3.5"
Casey

Windoes fit with a tight size, and their measuemetns are built to an exact (within some tolerance) size.

If you have a 60 inch rough opening the window size would be 60 inches minus about 0.5 inches (varies with how well you KNOW the dimension, including ANY deviation from perfectly flat on the top, bottom, and sides). for a net window size of 55.5 inches wide.

You have NOT specified a height, but it is also reduced to make sure the window fits te opening and has room for shims.

Depending on the width of the window framing the glass IS going to be slightly smaller to much smaller.

We understand what nominal means, and are trying to tell you it is NOT used in sizing windows.
There are way to many variables to even consider the idea.

A bay window for a 60 inch wide opening is VERY different from a single hung, a double hung, a triple hung, a jalousie, a casement, a hopper, an awning, a fixed, a bay, a bow. a garden, a tilt-turn, etc.

The manufacture adjusts the window components to make a window that will fit a specified rough opening size.

I’m reading your question more than 10 years later. I understood it perfectly bc I have the same question . Buying a 60” triple casement , and need to order custom cabs soon. How much wall space does a 60 inch casement take up once the window is installed and trimmed with millwork ? I’m leaving 3 inches between window and edge of cabinet , so that’s my margin of error . I’m guessing 65” total .

P.s. The nitpicking over your use of the word ‘nominal’ gave me a chuckle .

I am removing a 200 sectors narrow line Andersen double hung window, which based