Many cars these days have a miles to empty calculation. They all assume you will continue to drive exactly like you were for some preset distance/time previously, and then look at the amount of energy (whether that's fuel in an ICE or SOC in an EV) to establish the estimate. My ICE might show 200 miles to empty with 2/3rds of a tank left, or, closer to 330 or more if I'd been driving long-distance down the interstate versus running around town in stop and go traffic.
If you want a more accurate estimate of how much range the vehicle has, activate a route in the nav system. Then, it knows the terrain and speed limits. Otherwise, all it can use is your previous history...it doesn't have a clue whether the driving will be stop and go at an average of 20mph, or 65mph with lots of hills.
Once you've owned the car for awhile, you'll get a better feel for what it can do. One thing on the REx is that there's a fairly significant hit on range if you crank the heat up. The BEV has a heat pump, the REx does not. On an ICE, it uses waste heat from the engine, that is not possible on the REx in its current configuration as the REx just doesn't run all that often, and the plumbing to make use of that isn't that easy to accomplish without adding a lot of weight and complexity.
To give a a couple of examples:
- My i3 was in the relatively warm garage. I moved it outside to swap places with my ICE. The i3 sat overnight in really cold temperatures. Just the change in temperature dropped the indicated range to empty by nearly 10-miles.
- On more than one occasion, I've gotten into my BEV, driven over 10-miles, and the range to empty INCREASED...different weather and driving conditions than the previous use.
Those calculations are an estimate...you have to evaluate how it will relate to your next driving versus your previous use. Using the nav eliminates some of that uncertainty if you set a destination.