Tesla HW3 vs HW4 (AI4)
Two used Teslas can look identical and still have very different self-driving hardware. Here's how to tell which computer a car has, and why it now matters in Europe.
A buyer's guide from Tesla Inventory Europe · Updated October 2026
Every Tesla has an Autopilot computer and a set of cameras. Cars built until 2023–2024 use Hardware 3 (HW3), also called FSD Computer 3. Newer cars use Hardware 4, which Tesla now calls AI4, with a faster computer and higher-resolution cameras. For everyday driving and Basic Autopilot there is little difference. For Tesla's more advanced driver assistance, there is a big one.
Why it matters now
In April 2026 the Dutch regulator approved FSD (Supervised), the first approval in Europe, and several other European countries have followed since. The approved build runs on AI4. Tesla has acknowledged that HW3 cannot reach unsupervised self-driving, and its plans for HW3 owners — a reduced "Lite" version, trade-in discounts, a paid retrofit with limited availability — remain vague. If you want FSD now or later, an AI4 car is the safe choice. If you only need Basic Autopilot, a HW3 car is fine and usually cheaper.
Which models and years have which
| Model | HW3 | AI4 (HW4) |
|---|---|---|
| Model 3 | Legacy Model 3 built from about April 2019 (earlier cars have HW2.5 unless upgraded) | All Highland cars (from late 2023) |
| Model Y | Legacy cars built until early 2024 | Legacy cars from about February 2024 (Shanghai) or May 2024 (Berlin), and every Juniper Model Y |
| Model S / Model X | Cars built from about spring 2019 until early 2023 (older cars have HW2/2.5, or HW1 before late 2016) | Cars built from about March 2023 |
Approximate switch-over dates by factory. Cars made around these dates can have either computer, and registration can be weeks or months after production — always check the car itself.
How many used Teslas have each, right now
| Model | Used cars on sale | AI4 (HW4) | HW3 | Check in the car |
|---|---|---|---|---|
| Model Y | 1,199 | 13% | 81% | 6% |
| Model 3 | 529 | 21% | 78% | 0% |
| Model S | 9 | 22% | 44% | 33% |
| Model X | 7 | 43% | 0% | 57% |
Estimate as of 2026-10-31 for used cars on sale in Tesla's European inventory, based on each car's generation and first registration date. "Check in the car" means it was registered around a switch-over (including older cars that may have HW2/2.5). Updated daily.
How to check a specific car
- In the car: Controls (Settings) › Software › Additional Vehicle Information. The "Autopilot computer" line shows FSD Computer 3 or AI4. Ask the seller for a photo of this screen if you can't see the car.
- Front camera: on AI4 cars the camera housing behind the windscreen shows two red-tinted lenses and one black dummy lens; HW3 has three dark lenses.
- Side repeaters: the cameras in the front wing indicators have a red tint on AI4 cars.
- Generation: a Highland Model 3 or a Juniper Model Y is always AI4. On Tesla Inventory Europe the generation filter shows only those cars.
What it means for price
AI4 cars are mostly newer, so they cost more anyway. The comparison that matters is between legacy Model Y cars registered in 2024: two cars of the same age and mileage can have different computers, and the AI4 one is the better buy if self-driving features matter to you. Remember that FSD is now sold in Europe as a monthly subscription, which does not stay with the car, while FSD or Enhanced Autopilot bought outright by a previous owner does. Our guide on how to read a Tesla listing explains the Autopilot packages.
Browse AI4 Model Y (Juniper) →
Frequently Asked Questions
How do I check if a Tesla has HW3 or HW4?
In the car, open Controls (called Settings in newer software) › Software › Additional Vehicle Information and look at the "Autopilot computer" line: it shows FSD Computer 3 (HW3) or AI4 (HW4). From the outside, AI4 cars have red-tinted lenses on the front camera housing and on the side repeater cameras.
Does FSD (Supervised) work on HW3 cars in Europe?
The FSD (Supervised) build approved in Europe from April 2026 runs on the AI4 computer. Tesla has released a cut-down "Lite" version for HW3 elsewhere, but has not set out a firm plan for HW3 cars in Europe, so if FSD matters to you, buy an AI4 car.
Can HW3 be upgraded to HW4?
Not as a simple swap: AI4 also uses different cameras and wiring. Tesla had promised to upgrade cars whose owners bought FSD, but in 2026 it moved to trade-in discounts towards an AI4 car and, in some cases, a paid replacement of the computer and cameras, with limited availability and no firm Europe-wide plan. Don't pay extra for a HW3 car on the promise of an upgrade.
Do all new Teslas have HW4?
Yes. Every Model 3 Highland, every new Model Y (Juniper) and all Model S and Model X built since about spring 2023 use the AI4 computer. Only older cars on the used market still have HW3.
Guide by Tesla Inventory Europe (teslainventory.app), an independent site not affiliated with Tesla, Inc. Specifications, warranty terms and prices vary by market and change over time; always confirm current details with Tesla before buying.