Quick Summary:
- Check the fuel door or manual, most rentals specify Regular 87.
- US pumps show AKI numbers, lower than UK RON equivalents.
- In Florida, choose Regular 87 unless the car states Premium required.
- Avoid diesel by mistake, and keep the receipt for return queries.
If you are used to UK petrol labels, filling up a US rental car in Florida can feel unfamiliar. The good news is that it is usually simpler than it looks. Most mainstream rental vehicles are designed to run happily on the lowest unleaded grade, and the pump labels give you the key information once you know what you are looking at.
This guide explains how US octane numbers work compared with UK RON, how petrol is labelled at Florida filling stations, and what to put in the tank for typical car hire categories.
US octane numbers vs UK RON: why the numbers look lower
In the UK, petrol is commonly labelled by RON, Research Octane Number, such as 95 RON (regular unleaded) and 97 to 99 RON (super unleaded). In the US, pumps usually display AKI, Anti Knock Index. AKI is calculated as an average of RON and MON (Motor Octane Number), shown as (R+M)/2 on many pumps.
Because AKI is an average and MON is lower than RON, the US number looks lower for an equivalent fuel. As a rough rule of thumb, US 87 AKI is broadly comparable to about 91 to 92 RON, US 89 AKI to about 93 to 94 RON, and US 91 to 93 AKI to about 96 to 98 RON. You do not need to memorise conversions, you just need to follow what the car specifies in the US system.
So if you are thinking, “UK regular is 95, why does the US pump say 87?”, it is usually not poorer fuel. It is just a different measurement method.
How petrol is labelled on pumps in Florida
At most Florida filling stations you will see three common unleaded choices:
Regular, typically 87 AKI. This is the default for many everyday cars and a lot of car hire fleets.
Midgrade, typically 89 AKI. Some vehicles recommend it, but relatively few require it.
Premium, commonly 91 or 93 AKI depending on station and brand. This is for vehicles that specifically require higher octane, often certain performance engines or some turbocharged models.
You may also see E10 (up to 10 percent ethanol) as the standard blend. Many stations sell E15 (labelled “Unleaded 88”) and E85 for flex fuel vehicles. Unless your rental specifically states it is a flex fuel vehicle and permits E85, stick with the standard unleaded grades (87, 89, 91 or 93). Diesel is usually on a separate nozzle and clearly labelled, but it is still worth double checking before you lift the handle.
What most US rental cars recommend for car hire in Florida
For typical car hire in Florida, most compact, intermediate, full size, and standard saloon models are designed for Regular 87. Many crossovers and family SUVs in rental fleets also specify 87. That is why “Regular” is the safe first assumption, but you should still confirm on the car itself.
The most reliable places to check are:
The fuel filler door, often a sticker stating “Unleaded gasoline only” and sometimes the minimum octane, for example “87 octane minimum”.
The owner information in the glovebox or the vehicle infotainment manual section.
The rental agreement or vehicle information sheet, which sometimes notes the required fuel type.
If the label says “87 minimum”, that means 87 is fine, 89 or 93 will not typically harm the engine, but you are paying extra for little benefit in a standard engine. If the label says “91 required” or “Premium fuel only”, then you should use Premium to avoid knocking, reduced performance, or warning lights.
If you are picking up near Central Florida, the guidance is the same whether you are collecting from car hire at Orlando Airport locations or driving straight out onto the motorways. The fuel grade is about the vehicle specification, not the region.
Common scenarios: which grade should you choose?
Economy, compact, intermediate, standard cars: almost always Regular 87. This covers a large portion of car hire fleets.
Minivans and family SUVs: usually Regular 87, occasionally Midgrade recommended. Check the filler door.
Premium or luxury models: often Premium 91 or 93 required. If you are in a higher tier vehicle, treat Premium as likely until you confirm.
Performance models: Premium required. Some vehicles will run on 87 but with reduced power, but “recommended” vs “required” matters. Follow the wording on the car.
Hybrid rentals: generally Regular 87. Again, verify on the fuel door because models differ.
If you are collecting in South Florida, such as via Enterprise car rental at Miami or travelling around the Miami area, you will find plenty of pumps offering 87, 89 and 93. Availability is rarely an issue, even late at night on main routes.
Reading the label: “minimum”, “recommended”, and “required”
US vehicle stickers may use slightly different language than UK drivers expect:
Minimum or 87 minimum means do not go below that number. Using higher is usually acceptable.
Recommended means the engine can use lower without damage, but may not deliver the quoted performance. For an ordinary holiday itinerary, many drivers still use Regular if it is allowed, but it is your choice.
Required means you should use Premium. Repeated use of lower octane can cause knocking, reduced efficiency, and in some vehicles it may trigger a check engine light.
For straightforward car hire, choosing the minimum stated on the car is the sensible and cost aware approach.
How to avoid common refuelling mistakes in Florida
Do not assume “Premium” means “better for the car”. If the car is designed for 87, Premium usually provides no everyday advantage.
Do not confuse “Unleaded 88” with a higher quality petrol. It is often E15, and not all vehicles are approved for it. Stick to 87, 89, 91 or 93 unless the car explicitly allows E15.
Watch for diesel green handles. Many stations use green for diesel, but colour is not universal. Read the label and nozzle.
Keep the receipt. If there is any question at return, a receipt showing unleaded and gallons can be helpful.
Know how US pumps work. Many Florida pumps are pay at pump with chip and PIN, but some UK cards may ask for a ZIP code. If that happens, pay inside with the cashier instead.
Does fuel choice affect costs on a Florida road trip?
Yes, but mainly through grade pricing. Premium can be noticeably more expensive per gallon than Regular, so using it unnecessarily can add up on a longer drive. If your rental only needs 87, Regular is typically the best value. If the car requires 91 or 93, budgeting for Premium is simply part of operating that model.
Also remember that US fuel is sold by the gallon, not the litre. Your receipt will show gallons pumped and price per gallon. If you are comparing prices mentally to the UK, it helps to remember one US gallon is about 3.785 litres.
What about returning the car: should you fill up near the airport?
Many renters prefer to refuel shortly before drop off. Around busy hubs you will often see higher prices right next to terminals, so a station a little further out can be cheaper. If your plans include returning near Orlando, the same octane rules apply whether you used Orlando MCO car rental services or another pickup point. Use the grade stated on the vehicle, then keep the receipt until the return is complete.
If you are returning around Miami, the advice is similar for city locations such as Thrifty car rental in Downtown Miami. Choose the correct octane, avoid E85 unless clearly permitted, and allow enough time to refuel without stress.
FAQ
Q: If I normally use 95 RON in the UK, what should I choose in Florida?
A: Follow the label on the rental car. Most will specify Regular 87 AKI, which is normal in the US and not “lower quality”, it is measured differently from UK RON.
Q: Is “Regular” unleaded the same as “Unleaded” in the UK?
A: Regular in Florida is usually 87 AKI. It is unleaded petrol suitable for many US engines, but the octane number is shown in AKI rather than UK RON.
Q: What happens if I accidentally put Premium in a car that only needs Regular?
A: Usually nothing other than paying more. Higher octane does not typically improve performance or economy in engines designed for 87.
Q: How do I know if my rental car needs Premium?
A: Check the fuel door sticker or manual. If it says “Premium required” or gives a minimum of 91 or 93, you should use Premium.
Q: Are ethanol blends common at Florida stations, and should I use them?
A: E10 is common and generally fine. Avoid E15 “Unleaded 88” and E85 unless the car clearly states it is approved for those fuels.
