The usual thresholds
A minimum of 21 is the most common baseline, with 23 or 25 applied to larger, faster or more expensive vehicles. A few suppliers rent from 19 on the smallest classes.
Some companies also apply an upper limit, or ask for additional confirmation above a certain age. This is less common but does exist, so it is worth reading the terms rather than assuming.
Why the age matters to the supplier
Insurance pricing
Insurers price younger drivers higher. Suppliers pass that through as a young-driver surcharge rather than raising the headline rate for everyone.
Car class risk
Premium, sports and large SUV classes carry a higher repair cost, so their age floor is usually set above the economy classes.
The young-driver surcharge
Where a driver is under the supplier's standard threshold but above the absolute minimum, a daily surcharge normally applies. It is charged per day, so it grows with the rental length.
Check whether the surcharge is included in the quoted price or added at the desk — this is a frequent source of disagreement at handover.
Age applies to every driver
The age rule is not limited to the person who paid. Every named driver has to meet it, including an additional driver added later.
If a second driver falls below the threshold, they cannot legally drive the car, and the insurance would not respond if they did.
What to check before booking
The threshold for your class
Confirm the age floor for the exact class you are booking, not the supplier's general minimum.
The surcharge amount
Ask what the daily young-driver fee is and whether it is already in the total you can see.
Whether experience is also required
Age and licence-held period are separate conditions. Meeting one does not mean meeting the other.