Quick Summary:
- Check the fuel door label for the minimum octane before filling.
- Florida Regular is usually 87 AKI, roughly similar to UK 91 RON.
- If your hire paperwork says Regular, choose 87 AKI unless told otherwise.
- Avoid diesel unless the car and fuel cap clearly say diesel.
If you are visiting Florida from the UK, the petrol labels at US pumps can look unfamiliar. Instead of “95” or “98”, you will see “Regular”, “Midgrade”, and “Premium”, with a small number like 87, 89, or 93. The good news is that choosing the right fuel for your car hire is usually straightforward once you know what those numbers mean, and where to check what the vehicle actually needs.
The key difference is the octane rating system. In the UK, we talk about RON (Research Octane Number), commonly 95 RON (unleaded) and 98 RON (super unleaded). In the US, pumps typically show AKI (Anti Knock Index), sometimes written as (R+M)/2, which averages RON and MON (Motor Octane Number). Because of that, the US number is lower even when the fuel quality is comparable. That is why UK drivers often worry that “87” looks too low, when in reality it is often similar to the regular petrol you are used to at home.
What “Regular, Midgrade, Premium” mean in Florida
In Florida, most petrol stations offer three grades for petrol (gasoline).
Regular is usually 87 AKI. This is the most common fuel for everyday cars, and it is what many rental fleets are set up for. If your car hire agreement states “Regular unleaded”, this is typically the correct choice unless the car itself specifies otherwise.
Midgrade is usually 89 AKI. It is a middle option that some drivers choose if a vehicle “recommends” premium but does not strictly require it.
Premium is often 91 or 93 AKI, with 93 being common in many parts of Florida. If the fuel door says “Premium required” (or “91 AKI minimum”), then you should buy Premium.
US AKI to UK RON, a practical translation
There is no perfect one-number conversion, but a practical rule of thumb helps. Roughly speaking, UK RON is about 4 to 5 points higher than US AKI for the same fuel.
87 AKI (Regular) is roughly comparable to about 91 to 92 RON.
89 AKI (Midgrade) is roughly comparable to about 94 to 95 RON.
91 AKI (Premium in some places) is roughly comparable to about 96 to 97 RON.
93 AKI (Premium in many Florida stations) is roughly comparable to about 98 to 99 RON.
How to match the fuel to your car hire agreement
Start by separating two things: what the agreement expects you to return (fuel level and type), and what the engine requires (octane and fuel type). Your agreement commonly focuses on fuel level, such as “return full”, but some paperwork and vehicle stickers also mention the recommended grade.
1) Check the fuel door label. Most cars have a sticker inside the fuel flap stating the minimum octane, for example “Unleaded gasoline only, 87 AKI minimum” or “Premium unleaded 91 AKI minimum”. Follow this first, because it is specific to that vehicle.
2) Look at the dash and rental key tag notes. Some fleets put reminders such as “REG ONLY” or “PREMIUM” on the key tag. Use it as a clue, but if it conflicts with the fuel door label, trust the fuel door.
3) Match the pump label to the required AKI. If it says 87 minimum, choose Regular 87. If it says 91 minimum and the station sells 93 Premium, choose that Premium grade.
4) Keep the receipt. If there is ever a dispute about what you put in, the receipt shows the grade and the gallons.
If you are collecting a vehicle near major hubs, the same logic applies whether you are picking up around Orlando or Miami. For example, travellers arranging car hire at Orlando Airport for Disney often drive longer motorway distances where the correct grade supports smooth running. In South Florida, if you are comparing options like Payless car hire in Florida, the agreement will still expect the correct fuel type, even though the brand and depot processes may vary.
What about E10, ethanol, and “unleaded” wording?
Most petrol sold in Florida is E10, meaning up to 10 percent ethanol. That is normal, and most modern cars are designed to use it. You might also see E15 or “Flex Fuel” (E85) options at some stations. Unless your rental car is clearly marked as flex-fuel and you know it accepts E85, avoid E85.
At the pump you will also see the term “Unleaded”. That simply means petrol without lead additives and is standard for modern cars. If the fuel door says “Unleaded gasoline only”, that is the normal petrol pump, not diesel.
Diesel vs petrol, a common UK visitor mistake
In the UK, diesel is common in family cars, but in US rental fleets petrol is more typical. Only choose diesel if the rental vehicle clearly states “Diesel fuel only” and the fuel cap or fuel door is labelled accordingly.
Putting diesel into a petrol car (or petrol into a diesel car) can cause severe damage. If you are unsure, check the fuel door label before you lift the nozzle.
Choosing the right grade for popular Florida rental types
Many compact, midsize, and full-size saloons supplied for everyday use will specify 87 AKI. Larger people carriers and vans may also run on Regular, even if they feel “big”. Those picking up a people carrier through minivan rental in Brickell might assume it needs Premium, but most minivans are tuned for Regular.
SUVs can be mixed. Some turbocharged SUVs specify Premium, many do not. If you are selecting something like SUV rental in Miami Beach, check the fuel door on day one so you are not making decisions on the forecourt later.
If your rental is collected from a business district depot such as car rental in Doral, you will likely be near many stations with all three grades, making it easier to follow the exact requirement.
How to avoid fuel charges at return
Most visitors prefer a full-to-full arrangement, where you return the car with a full tank. The easiest way to reduce stress is to refuel close to the return location, keep the receipt, and avoid topping up too early in case you get stuck in traffic and burn more fuel than expected.
Finally, remember that “Regular” in Florida is not the same number as “regular” in the UK, but it is often the correct choice for a standard car hire vehicle. Check the label, match the AKI, keep the receipt, and you will be aligned with both the engine requirement and your hire agreement.
FAQ
Q: If I normally buy 95 RON in the UK, what should I buy in Florida?
A: 95 RON is roughly similar to about 89 AKI, but many US cars are designed for 87 AKI. Follow the fuel door label, which commonly permits Regular 87.
Q: Is 87 “Regular” too low for a rental car?
A: Not usually. 87 AKI is a normal minimum specification for many US-market engines, including plenty of rental fleet vehicles in Florida.
Q: My rental says “Premium recommended”. Do I have to buy Premium?
A: No. “Recommended” means the car can run on Regular, though it may perform slightly better on Premium. “Required” is the wording that means you must use higher octane.
Q: How do I confirm whether the car needs petrol or diesel?
A: Check inside the fuel flap and on the cap for “Unleaded gasoline only” or “Diesel fuel only”. Do not rely on assumptions based on what you drive in the UK.
Q: Can I use E15 or E85 ethanol blends in a Florida hire car?
A: Use the standard unleaded grades (typically E10) unless the vehicle is clearly marked as flex-fuel and the manual confirms it can take E85.
