The Tesla Model X electric crossover will achieve a maximum 257 miles of range in production-ready form.

Official U.S. Environmental Protection Agency range and efficiency ratings for the Model X were posted today, ahead of the first deliveries.

The first handful of Model X crossovers are expected to be handed over to customers tonight at Tesla's factory in Fremont, California.

DON'T MISS: Tesla Model X Configurator Now Live; Signature Series Starts At $132,000 (UPDATED)

So far, ratings for only two Model X variants are listed, although more models may be added at a later date.

The 257-mile range rating applies to the Model X 90D, which features all-wheel drive and the 90-kilowatt-hour battery pack unveiled for the Model S back in July.

This model is also rated at 92 MPGe combined (90 MPGe city, 94 MPGe highway).

Tesla will also offer a Model X P90D performance model at launch, with slight decreases in efficiency.

The P90D is rated at 250 miles of range--confirming Tesla's previous estimate--and 89 MPGe combined (89 MPGe city, 90 MPGe highway).

Perhaps not surprisingly, the larger and heavier Model X has lower range and efficiency ratings than a comparable Model S.

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The Model S 90D is rated at 270 miles of range and 100 MPGe combined (95 MPGe city, 106 MPGe highway), while the Model S P90D is rated at 253 miles and 93 MPGe combined (89 MPGe city, 98 MPGe highway).

That difference will likely be maintained in terms of performance as well.

A leaked online configurator for the Model X P90D shows a claimed 0 to 60 mph time of 3.2 seconds with the optional "Ludicrous" mode.

Tesla Model X prototype photographed on test, California, Feb 2015. Photo by Simerjit Dhaliwal.

Tesla Model X prototype photographed on test, California, Feb 2015. Photo by Simerjit Dhaliwal.

A Model S P90D so equipped will do 0 to 60 mph in 2.8 seconds.

The first production Model X crossovers made available to customers will all be fully-loaded P90D Signature Series models.

Base price was previously listed as $132,000, before any Federal, state, or local incentives.

MORE: Tesla Delivery Goal Fell Due To Slower Model X Production Ramp: Sources

Beyond that, Tesla CEO Elon Musk has said that a Model X will generally cost $5,000 more than a comparably-equipped Model S.

Tesla plans to unveil the Model X in production-ready form tonight, and deliver the first examples to their owners.

However, it may still take some time for Tesla to fully ramp-up production, and for the Model X to become more widely available.

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