- Type of surface (gravel or paved roads)
- Presence of Zero Cadence (Yamaha)
- Lights being on permanently (EU requirements)
- Ambient temperature
- Tire pressures
- Rider Fitness
- Overall weight
- Pedalling Cadence
You should state what kind of e-bike you plan to buy (mountain bike, city bike, speed pedelec, etc.) and what type of environment you intend to use it in. Also, is it a Bosch or a Yamaha drive? If so, what kind? All this information will allow people to give you a response that's as close as possible to your own scenario.
I presume you're interested in a haibike, since you're asking in that sub-forum! Everything Jayvee pointed out is true. I'm a bigger guy than you (Much), and have an Sduro Haibike 400wh battery. On a relatively flat ride and low winds I would expect 40-45 miles of range in the 2nd highest motor setting (based on a couple of 20 mile rides before I hurt my back last year). If it is very windy that would drop for me to around 3o-35 miles. On a very hilly ride that was also windy I'd expect mid-20s. If you end up with a 500wh bike, at 25% to those numbers.
At your weight, I would guess you'd get at least 25% better distances that I am able to at my weight. For reference, I pedal hard and contribute a lot to the ride, typically average speed around 15mph in urban bike path riding, and usually cruise at 18-19mph just under the limiter.
I plan on buying a Haibike Sduro HardNine 5.5, 500 watt, Yamaha drive. I am going to use it for my daily commute to and from work, mixed terrain, 15 mile round trip. Maybe some light offroad during the weekends.