I have developed a script in MATLAB that can detect peaks from datas and that can find FWHM of detected peaks. Scripts gives reliable results but crystallites sizes are different a little from this online calculator. Link to my data: http://pastebin.com/Ut9YgKGs Generated physical properties from MATLAB: http://pastebin.com/K0uEZ6Mr I made all conversion, degree to rad. The problem is that I don't have enough crystallography background to interpret the data. So how can I be sure from the values? Check also this if you are interested in script.