Hi, folks This may be FAQ but anyway, Has anyone made macro for MS-excel which calculates Micheaelis-Menten kinetics by Levenberg-Marquardt- curve fitting procedure? This would be very handy for the application I'm planning just now. So if you have the macro ready and you feel that you can share that work with others I would be very pleased. Ari-Pekka.Kvist at oulu.fi