This may already be out there but since i couldn't find it.. I'm slapping this together.... I just started working on it so I'm not sure yet that the Bolt calculator is accurate.
Should be working by weeks end. In no way affiliated with Caswell. Use at your own risk. Let me know if it's off so I can fix it.
http://216.242.56.15/Plating/Plating1.cfm