If you’ve ever rented a car, you might’ve noticed a short, four-letter code next to the vehicle description—something like “ECMR” or “IDAR.” These are known as SIPP codes, and they’re commonly used across the car rental industry to help you quickly compare vehicle types, regardless of brand or location.

Each code gives you an idea of what kind of car you’re booking. You’ll also see an example of a make and model listed (say, “Volkswagen Golf or similar”), but keep in mind that specific model might not always be available when you arrive to pick up your vehicle.

Here’s how the four-letter SIPP code breaks down:

🚘 1st letter – General car category (think economy vs. luxury)
🚙 2nd letter – Specific vehicle type (like SUV, convertible, or sedan)
⚙️ 3rd letter – Transmission and drive (manual, automatic, 4WD, etc.)
⛽ 4th letter – Fuel type and special features (such as air conditioning or hybrid fuel)

If you’re curious about the full breakdown of what each letter stands for, the ACRISS website has a handy reference list worth checking out.