Tesla HW3 vs HW4 on a Used Car: How to Tell, and What It Means for FSD

Personal opinion, not affiliated with any dealership.

"Is it HW3 or HW4?" might be the most common question I get about a used Tesla now. It's the self-driving computer and camera set the car was built with, and it decides how well Full Self-Driving (FSD) runs and what it will be able to do down the road. You can't see it on the window sticker, and the model year alone doesn't always tell you.

Here's how I check it, what each one actually does as of October 2026, and how I'd decide between them.

The short version

HW3 (Tesla now also calls it AI3) went into most Teslas from 2019 until 2023. It runs FSD (Supervised) today, but in April 2026 Tesla's CEO said HW3 won't get unsupervised FSD. [1]
HW4 (AI4) brought a faster computer and sharper cameras, starting with the Model S and X in early 2023. It gets the newest FSD builds first, and it's the hardware Tesla is aiming its unsupervised plans at. [2][15]
The check takes ten seconds on the car's screen: Controls > Software > Additional Vehicle Information. [4]
If FSD is the main reason you want the car, I'd stretch for HW4. If it isn't, a well-kept HW3 car is still a great buy.

How to tell which one a used Tesla has

1. The screen (the only check I fully trust)

Sit in the car, tap Controls > Software, then tap Additional Vehicle Information. Look for the Autopilot computer line. [4][2] On the cars I've looked at, it reads something like "Full Self-Driving Computer 3" or "Full Self-Driving Computer 4." Older cars may show 2.5.

Model 3 Software screen with the Autopilot Computer line and Additional Vehicle Information link (vehicle ID blurred) — This is the line to read: Autopilot Computer, then tap Additional Vehicle Information.

If it shows 2.5, that car needs a computer upgrade before it can run FSD at all. I cover that in my Model 3 by-year guide. Short version: Tesla does it free if the car has purchased FSD; if you only want to subscribe, Tesla lists the upgrade at $1,000 plus tax, installed. [4]

2. Build date (a good first filter from the listing)

Model	HW4 starts (approx.)	Notes
Model S and X	Early 2023 builds	First HW4 cars delivered around March 2023 [2][5]
Model Y	US builds from about late May 2023	Many 2023 Ys are still HW3, so check [2][6]
Model 3	The refreshed 2024 car ("Highland")	2017 to 2023 Model 3s are HW3 (or 2.5 on early cars) [2]
Cybertruck	Every one	HW4 from the start [7]

Model S Plaid interior with the yoke steering wheel in highway traffic — The Plaid's yoke. S and X built from early 2023 use HW4; confirm on the screen.

Stainless Cybertruck parked in the sun — Cybertruck: HW4 from the start.

The Model Y is where people get caught. The changeover happened partway through 2023, so a 2023 Y can be either one. My Model Y by-year guide walks through the eras. People often ask if the title or the car's ID number tells you. In general it doesn't spell out the computer, so treat the build date as a rough hint, and the car's own Software screen as the answer.

3. The cameras (when you can't get inside)

HW4 cameras have a reddish tint to the lens. Look at the windshield camera housing behind the mirror: HW4 cars show two red-tinted lenses plus a dummy one, while HW3 cars have three working cameras. The side repeater cameras on the front fenders also look different on HW4, with the same tint and a narrower turn signal strip. [2]

That's handy when you're walking a lot, but confirm it on the screen before you buy.

What's actually different

The computer. HW4 has much more processing power and memory. Tesla's CEO said HW3 has only one-eighth of HW4's memory bandwidth, and that's the main reason he gave for HW3 not getting unsupervised FSD. [1]

The cameras. HW4's front cameras have a much higher resolution than HW3's, and the tint is meant to help in low light. [2]

The software. Tesla now ships FSD as two branches. HW4 cars run the full version 14 builds. HW3 Model 3s and Model Ys got a slimmed-down "v14 Lite" starting in July 2026. [8][9] Tesla's own release notes say it was distilled from the HW4 version and that it added parking, unparking and reversing, plus arrival options for where the car should park. [9] As of this week, HW4 cars are getting v14.3.13 while HW3 cars get v14.3 Lite in the same update. [10]

The pattern I've seen for years still holds: features show up on HW4 first and come to HW3 later, if they come at all, and they don't always run as smoothly. [3]

How they drive: my take

This is my opinion, and it's the honest answer I give anyone who asks.

If FSD is the main reason you're buying a Tesla, seriously consider a HW4 car. I think HW4 drives better than most people do. It feels confident.

HW3 is still great. But the way I describe it, HW3 drives like a teenager who's had a license for about a year. It gets the job done most of the time, but it can be buggy, and it struggles in parking lots and tight spots, where it can get overwhelmed and hesitate. HW4 handles those same spots with a lot more confidence.

A few things I've noticed driving both:

Reaction time. HW4 reacts quicker, and in my experience it nags you less.
Parking. HW4 will find a spot and park itself, including backing in. The v14 Lite update added parking to HW3, but on my HW3 car it's still hit or miss, and I wouldn't count on it yet. It has a hard time in lots with faded lines that are due for repainting. In a big mall parking lot where everything is laid out straight and clearly marked, it parks itself pretty reliably.
On the open highway, the gap is smaller than people think. It shows up in the hard stuff: busy lots, tight streets, odd intersections.

View over the dash on a rainy street with the driving visualization on screen — Rainy-day driving with the visualization up.

Model X interior on a highway with Autopilot visualization on the instrument cluster — Highway driving in a Model X with the visualization in the cluster.

What HW3 does well

I don't want to undersell HW3. On my own HW3 car, FSD handles winding roads through the woods, residential streets and night highway driving with real confidence. That's what my driving clips show.

HW3 FSD (Supervised) on a winding road through the woods, the kind of drive it handles confidently.

More of the same wooded road on HW3.

HW3 on a residential street.

Neighborhood streets are an HW3 strength.

HW3 FSD on a Northwest forest road.

Night highway driving on HW3, as the car sees it.

HW3 FSD at night.

Its weak spot is parking and tight maneuvering, not everyday driving.

If FSD isn't a priority for you, a well-kept HW3 car is still a great buy, and that's often where the value is. You still get the same basic car, the same Supercharging and the same over-the-air updates. Just go in knowing what it is.

FSD on a used car today

FSD is subscription-only now. Tesla stopped selling it outright, and it lists one monthly subscription price, with no separate HW3 rate. Check Tesla's site for the current price. [11][12] That changes the math on a used car in two ways.

Subscribing on HW3. You pay the same monthly price for a version that trails HW4. The upside is you can cancel anytime, so it's a low-risk way to see if you even like FSD. [12]

A car that already has purchased FSD. Tesla's support page says that if the previous owner bought FSD outright and didn't transfer it to another car, it stays with the vehicle. Tesla's transfer program ended March 31, 2026. [11] On a HW4 car, that saves you the monthly fee. On a HW3 car it's still worth something, but it only gets what HW3 can run.

Before you pay extra for "FSD included," check Controls > Software for Full Self-Driving Capability in the included package, and see my pre-purchase checklist for how to confirm it survives the account transfer. [11]

The HW3 upgrade promise: where it stands

This is where a lot of buyers get bad information, so here's where things actually stand as of October 22, 2026.

April 2026: Tesla's CEO said HW3 can't do unsupervised FSD. For owners who bought FSD, he described two options: a discounted trade-in toward a HW4 car, or a retrofit that replaces both the computer and the cameras, done at small dedicated facilities in major metro areas rather than service centers. [1][13]
July 2026: on the next earnings call, there was still no cost, timeline or process. [14]
October 2026: HW3 retrofits didn't come up at all on the Q3 call. [15]

So no price, no dates, and no published rule on who qualifies. Tesla also hasn't said whether a second owner of a car with purchased FSD counts. Tesla said in 2024 that it didn't plan to retrofit HW4 into older cars at all, and that changed. [2][1] Plans can keep changing, so I wouldn't pay a premium for a HW3 car because of a hoped-for upgrade. Price it as the car it is today.

Listing mistakes I see all the time

"FSD hardware" or "FSD capable" in an ad. Every HW3 and HW4 car is technically capable of running FSD. That phrase tells you nothing about which computer it has or whether FSD is actually on the car.
Autopilot sold as FSD. Plenty of sellers mix up basic Autopilot, Enhanced Autopilot and FSD. Only the software screen settles it.
"It's a 2023, so it's HW4." Not for a Model 3, and only maybe for a Model Y.
A subscription mistaken for ownership. If the last owner subscribed, it leaves with them, and you'd start your own subscription. [11]

Don't wait forever for the next one

Tesla has also talked about newer computers coming after HW4. [13][15] There will always be a next one. If you need a car now and FSD matters to you, HW4 is the current hardware, and it's what Tesla's self-driving work is built around. [3] If you buy HW3, buy it for the price and the car, not for promises.

Quick decision guide

FSD is the main reason you want a Tesla: shop HW4. That's an S or X built from early 2023, a Model Y from about mid-2023, a 2024 or newer Model 3, or any Cybertruck. Confirm it on the screen.
You'll use FSD sometimes: a HW3 car with a subscription when you want it can work fine. Try v14 Lite on the test drive if the car has it.
FSD doesn't matter to you: buy the best-kept car in your budget. HW3 is fine.
Any HW2.5 car: budget for the computer upgrade if you ever want FSD, and remember it lands you on HW3, not HW4. [4]
A 2026-order car without FSD: don't assume it has Autosteer. New Model 3s and Ys ordered from early 2026 come with Traffic-Aware Cruise Control only; lane centering needs the FSD subscription. [16]

What I check on every car

Controls > Software > Additional Vehicle Information: the Autopilot computer line. Make sure it matches the ad.
Controls > Software: whether Full Self-Driving Capability is listed in the included package. [11]
The software version, so you know which FSD branch it's on (Lite or full).
The windshield camera housing for cracks and haze, and all cameras for clean, clear images. Look at the camera view on the screen.
A test drive with FSD on, if it's active, through a parking lot and a tight street, not just the highway. That's where you'll feel the difference.

Then go through the rest of my checklist and the battery health guide.

Sources

The Verge, Elon Musk admits that millions of Tesla vehicles won't get unsupervised FSD (Apr 22, 2026): https://www.theverge.com/transportation/917167/elon-musk-tesla-hw3-fsd
Not a Tesla App, How to Check If Your Tesla Has Hardware 3 (HW3) or Hardware 4 (AI4) (Aug 8, 2024): https://www.notateslaapp.com/news/2173/how-to-check-if-your-tesla-has-hardware-4-ai4-or-hardware-3
Electrek, Tesla will build factories just to retrofit millions of HW3 cars (Apr 22, 2026): https://electrek.co/2026/04/22/tesla-will-build-factories-just-to-retrofit-hw3-cars-it-said-could-do-fsd-but-cant/
Tesla Support, AI Computer Installations (computer check and upgrade): https://www.tesla.com/support/ai-computer
Not a Tesla App, Tesla Delivers First Hardware 4.0 Vehicles (Mar 2023): https://www.notateslaapp.com/news/1246/tesla-delivers-first-hardware-4-0-vehicles-but-without-autopilot-and-tacc
Teslarati, Tesla begins shipping Model Y with Hardware 4 (May 25, 2023): https://www.teslarati.com/tesla-begins-shipping-model-y-hardware-4/
AutoPilot Review, Tesla Hardware 4 (AI4): https://www.autopilotreview.com/tesla-hardware-4-rolling-out-to-new-vehicles/
Not a Tesla App, Tesla FSD V14 Lite for HW3 Vehicles Begins Public Rollout (Jul 2026): https://www.notateslaapp.com/news/4468/tesla-fsd-v14-lite-starts-rolling-out-publicly
Not a Tesla App, Update 2026.20.6.10 (FSD 14 Lite) release notes: https://www.notateslaapp.com/software-updates/version/2026.20.6.10/release-notes
Teslascope, Software Updates (2026.38.5.10: HW3 v14.3 Lite, AI4 v14.3.13), checked Oct 22, 2026: https://teslascope.com/software
Tesla Support, Full Self-Driving (Supervised): https://www.tesla.com/support/fsd
Tesla Support, Full Self-Driving (Supervised) Subscriptions: https://www.tesla.com/support/full-self-driving-subscriptions
Not a Tesla App, Tesla Announces HW3 Upgrade Plan, Trade-In Discount and Confirms No Unsupervised FSD for HW3 (Apr 2026): https://www.notateslaapp.com/news/4034/tesla-announces-hw3-upgrade-plan-trade-in-discount-and-confirms-no-unsupervised-fsd-for-hw3
Electrek, Tesla still has no real plan for Hardware 3 owners promised FSD (Jul 22, 2026): https://electrek.co/2026/07/22/tesla-hardware-3-fsd-no-plan-musk-earnings-call/
Electrek, Tesla skipped the most important shareholder question on its earnings call (Oct 22, 2026): https://electrek.co/2026/10/22/tesla-skipped-hw3-shareholder-question-earnings-call/
InsideEVs, Tesla removes Autosteer from all Model 3 and Model Y trims (Jan 2026): https://insideevs.com/news/785225/tesla-removes-autopilot-base-models/