Adults over 21 can earn a high school diploma or its equivalent through several paths, including adult education programs, online accredited high schools, and equivalency exams like the GED or HiSET. Your best option depends on how many credits you already have, how quickly you want to finish, and whether you prefer coursework or a single exam.
Your Main Options After 21
Once you’re past the typical age for public high school, you have three realistic paths to a credential that colleges and employers recognize. Each works differently and suits different situations.
An adult high school diploma involves completing actual coursework, either in person or online, and earning a traditional diploma. This is a good fit if you were close to graduating and only need a handful of credits, or if you prefer structured learning over a high-stakes test.
A high school equivalency credential (GED, HiSET, or TASC, depending on your state) lets you demonstrate high school-level knowledge by passing a set of exams rather than completing coursework. The GED, for example, is a four-subject test covering language arts, math, social studies, and science. The entire exam takes about seven hours. If you’re confident in your academic skills and want the fastest route, this is usually it.
A state-funded adult education program can help you prepare for either path, often at no cost. These programs are funded through the federal Workforce Innovation and Opportunity Act (WIOA), and they offer classes in reading, writing, and math alongside direct preparation for equivalency exams. Many states run these through community colleges, workforce development centers, or dedicated adult learning centers.
Free Adult Education Programs
Most states offer free adult education classes specifically designed for people who didn’t finish high school. These programs are federally supported through WIOA and typically include Adult Basic Education (ABE) to strengthen foundational skills, plus targeted prep for the GED or HiSET. Because they’re publicly funded, tuition is free for eligible residents.
To find your local program, search for “adult education” on your state’s department of education or workforce development website. You can also call 211, a national helpline that connects people with local services. Classes are usually offered at community colleges, public libraries, or standalone adult learning centers. Many programs now offer evening and weekend schedules to accommodate work.
Some states also run adult high schools that award an actual diploma rather than an equivalency credential. These schools let you enroll, take classes, and graduate just as you would have in a traditional setting. Availability varies widely by location, so check with your state or county education office.
Earning an Equivalency Credential
If you want the quickest path, an equivalency exam is hard to beat. The GED is the most widely recognized option and is accepted in all 50 states. The HiSET is an alternative offered in many states, and a few states use the TASC exam instead. All three test the same core subjects: math, language arts, science, and social studies.
You can schedule each subject separately, so you don’t have to pass all four in one sitting. If you fail a subject, you can retake it. Testing fees vary by state but generally run between $30 and $40 per subject, putting the total cost somewhere around $80 to $160 for all four. Some states cover testing fees entirely for residents in adult education programs.
Most colleges and employers treat a GED the same as a traditional high school diploma. The GED Testing Service notes that most colleges and employers view the two credentials equally, and earning a GED can lead to higher earnings compared to having no credential at all. If your goal is to qualify for college admissions or meet a job requirement, an equivalency credential will get you there.
Accredited Online High Schools
If you’d rather earn an actual diploma through coursework but can’t attend classes in person, accredited online high schools are a solid option. These programs let you work at your own pace, which is especially useful if you’re balancing a job or family responsibilities.
Penn Foster is one of the more established options. It holds national accreditation from both the Distance Education Accrediting Commission (DEAC) and Cognia, plus regional accreditation from the Middle States Association’s Commission on Secondary Schools. That layered accreditation matters because it signals to colleges and employers that the diploma meets recognized standards.
Costs for private online programs typically range from a few hundred dollars to around $1,500 for the full program, depending on how many credits you need. Some programs let you transfer credits you already earned, which can shorten your timeline and reduce costs. Completion time varies, but many students finish within one to two years. If you only need a few credits, you could be done in months.
How to Spot a Diploma Mill
Not every online program is legitimate. Diploma mills are operations that sell credentials with little or no actual coursework. A diploma from one of these outfits won’t be accepted by employers or colleges, and you’ll have wasted your money.
Before enrolling anywhere, check for accreditation from a recognized agency. Legitimate accreditors for high school programs include regional accrediting bodies (like the Middle States Association or the Western Association of Schools and Colleges), Cognia, and the Distance Education Accrediting Commission. You can verify an institution’s accreditation status through the U.S. Department of Education’s database.
Red flags include programs that promise a diploma in days or weeks with no coursework, charge a flat fee for an instant credential, or don’t appear in any recognized accreditation database. If a program doesn’t clearly list its accreditor on its website, that alone is reason to walk away.
Which Path Is Right for You
Your choice comes down to a few practical questions. How many credits did you finish before leaving high school? If you were a semester or two away from graduating, an adult diploma program that accepts transfer credits could be the most efficient route. If you left early or don’t have transcripts available, an equivalency exam lets you start fresh without worrying about past records.
How much can you spend? Free state-funded programs and equivalency exams keep costs minimal. Online diploma programs charge tuition but offer flexibility. If budget is tight, start by calling your local adult education center to see what’s available at no cost.
How fast do you need the credential? The GED can be completed in weeks if you’re ready for the material. A full diploma program takes longer but may feel more thorough. Either way, you’re looking at a credential that opens the same doors: college enrollment, better job prospects, and meeting the baseline requirement that most employers expect.