I use an online service to track my finances, and in this system I track the value of my high-value assets, including my vehicles. I typically use KBB's numbers for this, which I can look up online at KBB's website. However, I'm not seeing any option to look up values for the 2018 Prius, in any of its variations - they're simply not on the list. 2017 Prius cars are available, though. Anyone know what's up with this?
An accountant or financial planner can you tell you how to calculate the depreciation value of a new car, or you can google that question... KBB is for used cars not new cars. And the depreciation of a new car, is a pretty big tax deduction if you set it up correctly.
There probably haven’t been enough reported sales of 2018 Prius or Prius Prime cars as used cars to establish reliable values. If you need an estimate, just use the value of a 2017 car with similar equipment and mileage. As @PriusCamper kindly points out, if you’re using the car in a business, talk with your accountant or tax advisor, or see IRS Publication 946, How To Depreciate Property (PDF), but keep in mind that depreciation for accounting or tax purposes, generally computed using fixed formulas, is different than depreciation as the decrease in fair market value over time.