Dogtrousers
Kilometre nibbler
There are a number of sites on the web that do calculations based on hill gradient, rider weight, position etc. and provide wattage or times and so on.Is there a formula to calculate how much distance cycled on the flat equates to how many meters climbed. might end some arguments
You may be able to use these to cobble together a formula, but crucially you must ensure that it proves conclusively that your mate is a lazy wimp. It's of no use otherwise.