Originally Posted by Land-of-Miles
All HH points are earned per US$ equivalent not £ it can thus be really random determining how many points will be accrued per stay. I am still in dispute with HH about one recent stay where the conversion rate was <£1 = $1.50 (the first and only time this has happened).
Fundamentally though HH seem quite content to make it up as they go and there is nothing which can effectively be done to stop them.
I've always assumed they took the 17.5% Value Added Tax (VAT) off the final invoice before converting to dollars, because they don't give points for taxes. This would take the conversion nearer to £1 = $1.76 rate. Still not as good as current exchange rate of about $1.83 to the pound, but similar to rates that banks give. In answer to the original question, HHonors appears to give about 6.6 HHonors points to the pound on the final invoice, but this will obviously vary with the exchange rate.