There are many ways people measure frames. It's important to measure correctly to ensure your art work will fit.
The most important factor of measuring is to ensure you are measuring the glass size, and not the physical frame size. Different frame mouldings result in different physical sizes, this affects how big the frame will look on your wall, but does not change what size art work can fit.
As you can see above, both frames are made to fit a 5" x 4" photo, but the one on the left has a much smaller frame moulding.
If you already have frames you want to match, you must measure the glass size, and not the physical width of the frame.
Turn the frame over so you have the back and measure the opening size of the frame. The size of the backing card or the glass is the size of the photo the frame will fit.
Frame moulding width
Sometimes our frame mouldings are available in various thicknesses. This changes the overall size of the frame but not the size of the glass size. If you already have a style of frame and wish to purchase another one to fit, but there are multiple thicknesses. Then you can easily measure your current frame to see the thickness you have. We list the frames as separate listings with the thickness of the moulding in the title clearly. For example: 20mm Solid Wood Light Oak Veneer with Glass
Simply measure the width of the frame thats visible from the front.
The example below shows the 3 different widths Light Oak Veneer is available in and how to measure.
You can see below 3 different widths of the same moulding.