HomeReplacementWindows.net - what is the most accurate way to measure my windows , so I know what size to buy?

what is the most accurate way to measure my windows , so I know what size to buy?

I want to put vinyl replacement windows in my house, but not sure how to measure them. I want to make sure I buy the right size.

I've been told that you measure the inside frame size. I think the angle of the window frame is important too, but I'm not sure how to measure that.
Personally, in my opinion, it's worth it to have professionals measure and replace windows, especially if you don't know what you're doing. That's a mighty important feature and one doesn't want to mess it up. Sometimes companies don't honor warranties if they aren't installed by a professional.

If you can remov the inside trim you can get the rough opening size or figure that if you add 1 1/2 inches to the insie measurement that will work too.

LOWE'S has Pella replacement windows and a brochure on them.
You measure the inside of the opening left when you remove the sashes, so for the width, raise a window and measure the inside of the track side to side. then you measure the height from the bottom inside edge to the top inside the stop... it's not as hard as it sounds and unless your house was built by a wacko it will be a standard size like 32 x 54, count them up and multiply by $150.00 and order 'em up.. I'm getting ready to get mine.
The important thing is to get the sill seal tape and 1 tube of caulk per window, to make them weather tight, good luck!
With respect to professional installation, if your meticulous in your repair and follow the directions to the letter you will have a better installation of almost any project, the "pros" always use short cuts, the quote for our windows was over $11,000 more than twice the cost of windows alone and they are made to slip in standard size sashes, try one in back before you spend the extra money.