Tesla CEO Elon Musk said it would happen months ago, and now the EPA has finally rated the Model S at over 400 miles of range.

Although the agency's website hasn't been updated with the new figures, Tesla said Monday that its Model S Long Range Plus has an EPA range rating of 402 miles. It's the first time an EV has cracked the 400-mile mark.

The particular variant of the Model S is already available to order on Tesla's website, with its starting price coming in at $74,990.

While it doesn't offer the insane 0-60 mph time of 2.3 seconds that the latest Model S Performance offers, the Model S Long Range Plus is hardly slow with its 0-60 time coming in at 3.7 seconds. The top speed is 155 mph and the car also benefits from the added traction of all-wheel drive.

2020 Tesla Model S

2020 Tesla Model S

Tesla has continued to refine its Model S since the battery-electric sedan first arrived in 2012. Back then the car had a range of 265 miles, which was leading edge at the time. To achieve the latest range gains, Tesla engineers made numerous tweaks to the Model S sedan's hardware and software.

Some key measures included reduced weight, more aerodynamic wheels, tires with reduced rolling resistance, and a more efficient rear motor. The motor's mechanical oil pump was swapped out with an electric oil pump that's able to provide ideal lubrication regardless of vehicle speed.

Tweaks were also made to the transmission in the front motor, as well as to the regenerative braking system. The latter is now able to kick in at lower speeds and deceleration rates, meaning more energy can be recovered and sent to the battery back.

Tesla's updates to the Model S are far from over. The automaker has promised a new performance option called Plaid that's due later this year and will offer feature a new tri-motor setup.