UK vs US Military Entry Requirements: Age, Nationality, Education and Medical Compared

The British Armed Forces take recruits from 16 and the US services from 17, and the upper age limit runs from 28 (US Marine Corps) to 54 (RAF) depending on the service and role. Both countries then add checks on nationality, education, health and criminal record. This guide sets out the published entry rules for each service, side by side, as listed on the official recruiting sites in October 2026.

Age limits compared

Age is the first filter. The UK sets limits per service and per role. The US sets one range per branch for active duty.

Both countries require parental consent for applicants under 18. The US figure is 17 with parental consent and 18 without, according to the Today's Military eligibility page. The Army, Navy and RAF pages each state that under-18s need parental consent. USA.gov adds that in some cases applicants can be older than the limits above, so ask a recruiter before ruling yourself out.

Reserves

The British Army Reserve accepts applications from 17 years 9 months. Most reserve soldier roles stay open until 47 years 6 months, and applicants must join by their 48th birthday. Reserve officers must apply by 48 years 9 months. Some specialist reserve roles have higher limits. US reserve and National Guard age ranges differ by branch, so check the branch recruiter page for your chosen component.

Nationality and residency

The Army sets out the detail on its nationality page. At the time of writing, the Commonwealth application window is closed except for musician roles, and applications from the 2024 window without a Recruit Bounty Scheme sponsor will be rejected. Commonwealth recruits receive exempt immigration control status while serving. The Army lists a minimum income requirement of £23,496 for family visas (as of 11 April 2024), so confirm the current figure with a recruiter or the Home Office before you plan around it.

The Royal Navy accepts UK or Irish nationals, and Commonwealth citizens who apply from their own country (age 18) or as UK residents (age 16) with a valid passport. Some roles carry stricter security requirements.

Education and qualifications

The Army also offers a fully funded BSc or MSc in Leadership and Strategic Studies to officers through the Army Higher Education Pathway, developed with Henley Business School. Details are on the Army qualifications page.

Medical, fitness and appearance

Both countries run a medical examination as part of enlistment, and both test fitness. The UK publishes more numeric detail per service than the US recruiting pages do.

• Royal Navy height: a minimum of 145 cm, 151.5 cm for aviators and 157 cm for submariners.
• Royal Navy body mass index: over 28 or under 18 may delay or bar entry. Exceptions may apply if your waist measures under 94 cm.
• Royal Navy asthma and medication: asthma within the last four years may delay or bar entry, as can any condition needing regular prescription medication or GP review.
• Royal Navy tattoos and piercings: most tattoos do not prevent entry if they are not offensive or obscene. Tattoos on hands, neck and throat are acceptable if they follow the guidelines. Flesh tunnels are a barrier to entry.
• RAF: a medical test, a family-origin questionnaire that screens for sickle cell trait (the RAF says the trait is unlikely to prevent you joining), and role-specific fitness standards. Some roles need a swimming test or a driving licence.
• US services: a medical exam and a physical fitness test, with standards that vary by branch. Ask a recruiter for the branch tests.

Criminal record

A conviction does not automatically stop an application on either side. The Army tells applicants to disclose their history at the first chat with a recruiter. Spent convictions are forgotten after a rehabilitation period, unspent convictions must be disclosed, and for some roles spent convictions must be declared as well. Hiding a conviction can lead to prosecution later. Pending charges must be reported and can delay an application.

The US picture varies by branch, according to Today's Military. Felons and people with multiple convictions are generally ineligible, though waivers exist. The Army considers waivers case by case. The Marine Corps requires a clear background check and no felony convictions. The Navy disqualifies applicants with a felony involving violence, domestic violence, illegal drugs or sexual misconduct. The Coast Guard Recruiting Command can authorise case-by-case waivers.

What the comparison shows

The US age bands cluster tightly (17 to 28 at the narrowest, 17 to 42 at the widest). The UK gives wider ranges at the top, including 54 for the RAF and 47 years 6 months for most Army reserve soldier roles. The US requires the ASVAB for every enlistee, while the UK pages describe selection at an assessment centre that varies by role. Anyone who left one country's forces and is weighing a move to the other should read the transition support comparison and the veteran population data for the wider context.