When Measuring For Steel Tab-Clip Straps, Measure From One Outside Edge Of The Frame, To The Other Outside Edge Of The Frame, Then Minus 1 Inch. (This Will Be Your Test Strap Measurement). [This Will Also Be Your Measurement For Calculating A Strap Order] After Trying One Strap You Can Decide To Add Or Subtract Length. Not All Frames Are A Constant Width, Some Will Flare Out At The Top Or Bottom. You May Need Straps Of Different Lengths On The Same Piece Of Furniture.