I use Ride with GPS for routing my rides. In my opinion it is the best software out there particularly for audax (randonneur) and touring.
At the end of a ride my Wahoo ELEMNT syncs with RWGPS and shows a plethora of metrics. One of these is ‘average watts’. As I don’t ride with a power meter and I have only entered my FTP and weight into my profile: How do they calculate my watts? I assume as I ride with a HRM, this may contribute.
It’s an estimate using gradient and speed and your weight. They usually suck… unless you’re on a serious hillclimb. Then it’s a bit more accurate (still nothing on a powermeter)
I’ve just been informed by Ridewithgps that what shows as “Average Watts” on your rides in Ridewithgps is actually “NP” (Normalized Power) and NOT Average Watts. This is why the value is so high. I’ve no idea why they would show NP and state it as Avg Power.