I have made a program which creates a centred navigation bar similar to the one on this site, with equally sized and spaced buttons. Choose the web page width, your desired bar width, and the number of buttons you would like and their widths. The relevant HTML/CSS code will then be produced.
Often, it will not be possible to have a certain button width, due to the navigation bar not being able to be perfectly centred. In this case you will automatically be given a slightly higher button width, so that the navigation bar can be exactly in the centre. Also, the bar width has to be an even number, along with the web page width.