The main difference between diplomas and GEDs is the age at which they are given. A diploma is awarded for completion of secondary school, while a GED is awarded for completion of high school or any equivalent level of education.
Diplomas are awarded by public schools or private institutions that are accredited by the state Department of Education (DOE). According to DOE rules, diplomas must be earned from an accredited public school or out-of-state public school not licensed in your state. The DOE only accredits schools that provide a high quality education to students who complete their education with a grade point average (GPA) of 2.0 or higher. In addition to meeting these academic requirements, students must also pass high-stakes tests in English language arts (ELA), mathematics and science.
The General Educational Development (GED) test is administered on paper or online and tests basic academic skills in reading, writing, mathematics, science and social studies. The test can be taken after high school graduation or prior to it. It does not lead directly to college credit but does qualify students for more advanced courses at community colleges or other types of postsecondary education programs.
The GED test was originally developed in 1942. Two primary reasons for developing the test were the number of American men being sent overseas to fight in World War II before they could complete their high school education, and the number of people leaving school early to join the largely industrial work force.
The General Educational Development tests are a group of four subject tests which, when passed, provide certification that the test taker has United States or Canadian high school-level academic skills. The GED tests cover four subjects: math, science, reading, and writing. Students who pass the test must also take a fifth subject test on social studies.

