tracking distance without equipment tip

Options
I am not one for heavy duty cardio but on days that I am not doing my regular thing I try to get a walk in or a bike ride...my only issue has been without a HRM trying to figure out the calories based on speed etc.

I have pretty standard routes in the town I live in and today I walked one of them and it took 40mins but I wasn't sure of my speed (I guesstimated at first it was 2.5mph) well then I was going to drive the route to find out how far it was but then I realized...

GOOGLE MAPS

I plugged in my route and it gave me the distance...figuring out my speed after that was easy...it was 3.5mph btw...so for those who aren't hardcore into cardio like me this might be an option.