What is comma?

A small device. A different way to share the drive.

comma four runs openpilot, software that helps steer a supported car and, on some cars, controls speed too. You stay the driver.

Three names, made simple

The company. The device. The software.

The company that makes comma hardware and develops openpilot.

The device mounted near your rearview mirror. It connects to a supported car through the correct harness.

The driver-assistance software running on the device. Your car determines which controls it can use.

What it does

openpilot helps keep a supported car centered in its lane while engaged.

Depending on the car, openpilot or the factory adaptive cruise controls gas and brakes.

A driver-facing camera checks that you are watching the road.

The part to understand first

You must watch the road and be ready to steer or brake immediately. It cannot handle every road, obstacle, or driving situation.

Do not use a video of someone else’s car as a promise of what yours will do.

The exact model, year, and required equipment matter more than the badge on the hood.

Start with your car, before the checkout.

Find its listed configuration. Then read the steering limits, gas and brake control, required package, and harness.

Is comma the same as openpilot?

No. comma.ai is the company, comma four is a device, and openpilot is the software it runs.

Does comma work with every car?

No. Support is specific to a model, year, and equipment package. Check the exact listing and current official requirements before buying.

Do I need Chestnut?

No. comma four can run standard openpilot without Chestnut. Chestnut is an optional compute upgrade for a larger driving model.

Car checked? Ready to choose?

Check the exact car requirements first. Then see the current comma four offer and the correct harness at comma.ai.

Referral disclosure: eligible new customers get $50 off. CommaGuide gets $50 after a qualifying purchase. Terms apply.

Your next step

Was this guide helpful?