One hour

That's right, I have solved the modern Greek formula for estimating time.

It is: X + 1 hour

You can apply it to just about anything. For example:

Someone says, "See you tomorrow at 3pm for lunch!" (You should show up at 4pm)

You get a text msg at 12:12pm "Meet me at the downtown square in half an hour" (You should show up at 1:42pm.)

Someone says, "That will take 5 minutes" (Correct estimate: 65 minutes).

This is pretty universal and you can use it anywhere. It's something I've got to start doing because I am the type of person that says they will be somewhere at a specific time & I usually come walking up 5 minutes early. The key is to have an iPod and a laptop with you at all times - I think that this will help me hedge as I adapt.

Other great formulas I have uncovered back in the USA:
Z x 1.1 = Woman's actual weight [whereas Z is stated weight]
(Y x .85) rounded down to nearest ten = Men's actual IQ [whereas Y is stated IQ]
S x 2 = Actual amount of women men have slept with [whereas S is stated amount]