It is very simple to do and usually does not require removal of the hinge from the window at all. Just follow the simple steps below to measure and identify which type of hinge you need. Step 1. Check the hanging of your window.
If the handle is on the SIDE of the window, you need SIDE Hung Window hinges.
If the handle is at the BOTTOM of the the window you need TOP HUNG hinges.
Top HUNG SIDE HUNG Step 2. Measure the length of the hinge.(A)
The length is the track part that you can see when you open your window. Your old hinge may be a 10" but if you can fit a larger hinge in then do that. Step 3. Measure the width of the hinge. (B)
Measure the width of the track that you have just measured, this could be either 15mm or 18mm.The most common one is the 18mm and is fitted on 90% of windows.