nPower prices?

That's 11.55%, because 2.695/2.416 = 1.1155.

That's 9.96%.

This last one looks highly suspect, at 188%. Might you mean from 16.6p to 19.0p? That would be 14.46%.

50 units over 100 days is only half a unit per day, that's pretty unrealistic. Might you mean 50 units per day? If so, it doesn't matter over how many days you take it. Also most people would use many more gas units than electricity units per day.

Anyway, it's clear that the gas is up by somewhere between 9.96% and

11.55%. To find out exactly where, just work out the daily costs, then compare those:

At 50 units per day your daily cost for gas would have risen from

35.1p + 50*2.416p (which is 155.9p) per day to 38.6p + 50*2.695p (which is 173.35p) so the increase is 11.19% because 173.35/155.9 is 1.1119.

Doing it for electricity, or for both together, is left as an exercise.

Makes more sense! E-On have just raised mine by 6.6% for the primary units (first xxx units consumed), but cynically they have raised the secondary units by 12.5%, thus making winter electricity relatively more expensive. :-(

It appears that we are in a round of fuel price increases, it will be time for me to look round when it settles...

Have you tried buying a legal version?

I don't think I have ever had Excel crash in about the last five years. Sometimes prior to that it would freeze if an enormous spreadsheet.

See the thread on Energy Supplier Transfer in uk.legal.moderated regarding timescales.

Yep, paid about £20 courtesy of my employers HUP - 2010 version as well.

Alas no, 6.60p to 19p is sadly correct!