An 18-year-old can be added as an additional driver on a rental car only in a narrow set of circumstances: at rental locations in New York or Michigan, or when the driver is traveling on official U.S. government or military orders. Everywhere else, the major rental companies will not add an 18-year-old to the agreement at any price, because additional drivers have to meet the same minimum age as the primary renter and that floor sits at 20 or 21 in most states.
The General Rule
Every major rental brand sets a minimum age for both primary renters and additional drivers, and none of the big companies allow 18-year-olds in most of the country. Hertz’s floor is 20 in the majority of states.1Hertz. Age Restrictions and Exceptions2Enterprise Rent-A-Car. What Are Your Age Requirements for Renting?3Budget Car Rental. Requirements for Renting FAQs Avis requires additional drivers to be at least 25 in most locations.4Avis Rent a Car. Can Your Rental Car Have an Additional Driver?
The additional driver rule tracks the primary renter rule. If the location’s minimum age is 21, an 18-year-old cannot be listed on the agreement in any capacity, no matter who is paying.
Where an 18-Year-Old Actually Qualifies
A handful of states have laws that force rental companies to lower their age minimums. New York and Michigan are the two where every major brand rents to 18-year-olds, and an 18-year-old can be added as an additional driver at those locations as well.1Hertz. Age Restrictions and Exceptions2Enterprise Rent-A-Car. What Are Your Age Requirements for Renting?
If your trip starts anywhere else, this is where the search usually ends. Willingness to pay a surcharge does not change the answer, because the age floor is a rental-eligibility rule, not a fee waiver.
Government and Military Travelers
Active federal employees and service members traveling on official orders can rent at 18 in any state, bypassing the normal state-based minimums. The renter needs travel authorization, a government ID, or a Government Travel Charge Card at the counter.5Defense Travel Management Office. Rental Car Program Enterprise’s government program sets 18 as the minimum age and accepts a military ID in place of a standard driver’s license.6Enterprise Rent-A-Car. Government Rate – Section: Official Government Travel
Government renters aged 18 to 20 may still see a young driver fee, but the Defense Travel Management Office confirms the fee is reimbursable. Drivers 21 and older on government orders pay no age-related fees at all.5Defense Travel Management Office. Rental Car Program
What It Costs to Add an 18-Year-Old
In the states where it is allowed, two separate charges stack on top of the base rental rate: a young driver surcharge tied to the driver’s age, and an additional driver fee for listing anyone besides the primary renter.
Young Driver Surcharge
Every company charges a daily surcharge for drivers under 25, and the amount typically jumps for the 18-to-20 bracket. Avis publishes some of the most detailed pricing: $84 per day for renters aged 18 to 20 in New York, $41 per day in Michigan, and $35 or $28 per day for 21-to-24-year-olds in the same states.7Avis. Minimum Age to Rent a Car Hertz charges a flat $19 per day for all renters under 25.8Hertz. Young Renters
The gap between brands is large. On a five-day rental, an 18-year-old’s surcharge alone runs about $95 at Hertz and up to $420 at Avis in New York, before the base rate or any other fees. Price-shopping across companies genuinely pays off for this age group.
Additional Driver Fee
On top of the young driver surcharge, most companies charge a separate daily fee to add any extra driver to the contract. Enterprise charges $15 per day per additional driver.9Enterprise Rent-A-Car. Can I Add an Additional Driver to My Rental? Some companies waive this fee for a spouse or domestic partner of the primary renter, but Avis requires the spouse to be at least 25 for the waiver to apply, which rules out an 18-year-old spouse.4Avis Rent a Car. Can Your Rental Car Have an Additional Driver?
Depending on brand and state, an 18-year-old added as an additional driver can realistically face $34 to $99 per day in combined surcharges. Ask for the full daily total before signing.
Vehicle Restrictions
Even where an 18-year-old is allowed to drive, the choice of car shrinks. Avis bars anyone under 25 from renting full-size SUVs, luxury vehicles, minivans, passenger vans, premium SUVs, and specialty cars. The available classes top out at full-size sedans, standard SUVs, convertibles, and premium cars.7Avis. Minimum Age to Rent a Car Other major companies impose similar limits with different specifics. If a group trip needs a large vehicle, a young additional driver can be a deal-breaker.
How to Add Them at the Counter
Both the primary renter and the 18-year-old usually need to be physically present at pickup. Adding a driver remotely or after pickup is either impossible or requires returning to the rental office.
The 18-year-old brings a valid, unexpired driver’s license. If the license is in a non-Roman alphabet, an international driving permit or an official translation is required alongside the original. The primary renter brings their own valid license plus a major credit card in their name. Some Enterprise and Hertz locations accept debit cards, but this varies by location and may trigger a credit check.2Enterprise Rent-A-Car. What Are Your Age Requirements for Renting?10Hertz. Renting a Car Under 25? We’ve Got You Covered
The 18-year-old signs the rental agreement, and their name and license details are formally added to the contract. Keep the paperwork. After any accident, the first question anyone asks is whether the driver was listed on the agreement.
Never Let an Unlisted 18-Year-Old Drive
Skipping the additional driver fee to save $15 a day can become a five-figure mistake. If a person who is not on the rental agreement gets into an accident, the rental contract and every insurance product attached to it can be voided. The loss damage waiver, the supplemental liability coverage, personal accident insurance, all of it disappears as if it had never been purchased. The primary renter becomes personally responsible for the full cost of vehicle damage, third-party injuries, and any related penalties.
The unauthorized driver’s own personal auto insurance may also deny the claim on the grounds that the driver had no legal right to operate the vehicle. That can leave both the primary renter and the young driver exposed to the full cost of an accident with no coverage from any source. No surcharge is expensive enough to justify that risk.
Insurance for a Young Additional Driver
If the primary renter carries personal auto insurance, liability coverage typically extends to a rental car and may cover authorized additional drivers. Collision coverage, however, often applies only to the primary renter, leaving a gap if the 18-year-old damages the vehicle. Policies handle this differently, so a call to the insurer before the trip is the single most useful piece of prep you can do.
Rental companies sell optional products that fill the gaps in personal coverage:
- Loss Damage Waiver (LDW) covers damage to the rental vehicle so you do not owe the company for repairs or replacement.
- Supplemental Liability Insurance (SLI) adds coverage for injuries or property damage you cause to others beyond what a personal policy provides.
- Personal Accident Insurance (PAI) covers medical expenses for the renter and passengers.
- Personal Effects Coverage (PEC) covers belongings stolen from or damaged in the car.
If the 18-year-old is not on the primary renter’s personal policy, buying at least LDW and SLI through the rental company is worth serious consideration. The daily cost is a fraction of what a minor collision would cost out of pocket.