In many countries, a certificate is a qualification attained in secondary education. For instance, students in the Republic of Ireland sit the Junior Certificate and follow it with the Leaving Certificate. Similarly, other countries have awards, for instance, in Australia the Higher School Certificate (HSC) in New South Wales, the Victorian Certificate of Education (VCE) in Victoria, etc., is the examination taken on completion of secondary education.
In many other countries, certificates are qualifications in higher education. For example, in the Republic of Ireland, the National Certificate, which is soon to be replaced by the "Higher Certificate". These have the titles Certificate (at an undergraduate level), Graduate Certificate (at an undergraduate level, but requiring the completion of a prior undergraduate degree for admission) and Postgraduate Certificate (at a postgraduate level). In Hong Kong, students take the Hong Kong Certificate of Education Examination. Certificate is below the standard of the associate degree and higher diploma, which are below the bachelor's degree. Postgraduate certificates are taken after the bachelor's degree and are sometimes more vocationally oriented than master's degrees.
In Australia, a certificate is a qualification offered by a university or other higher education provider which is shorter than a degree or diploma. Certificates are generally provided by TAFE colleges or non-academic Registered Training Organizations (often workplaces). There are four ranks of Certificate in Australia, indicated by Roman Numeral, e.g., Cert. IV in Horticulture. The time spent varies, but in general a Certificate I will be granted after a course of only a few weeks, while a Cert. IV may take up to six months. A Diploma directly follows Cert. IV and may rightly be considered equivalent to a hypothetical Certificate V.
In the United Kingdom, a Certificate of Higher Education (CertHE) requires successful completion of 120 CATS points at Level One. This is equivalent to one year of full-time university education, at first year level. Each credit point takes about 10 hours to achieve, and as such the CertHE is 1, 200 hours of study. This compares with 360 credit points for an undergraduate degree, and 240 credits for a Diploma of Higher Education.
In the United States, a certificate may be offered by an institute of higher education. These certificates usually signify that a student has reached a standard of knowledge about a certain vocational or professional subject. Certificate programs can be completed more quickly than associate's degrees and often do not have general education requirements.
In the State of Maryland, a Certificate of Merit was, until recently, issued to graduating high-school seniors who met certain academic requirements (such as completion of advanced courses and a cumulative GPA of 3.00); the statewide certificate has since been replaced by "endorsements" defined by each local school system.
It also may be awarded as a necessary certification to validate that a student is considered competent in a certain specific networking skill area in information technology. Thus a computer engineer or computer science graduation most likely will have to obtain additional certificates on and pertaining to the specific technologies or equipment used by the hiring corporation; if not, such employer may suffer unwanted penalties like foregoing (voiding the contract) the protections of a certain level of customer service or warranties.
Higher level academic certificates 
It is becoming more common for higher education institutions to award certificates to continuing education students. These certificates vary, usually involve rigorous courses, and can be affiliated with many associations. Examples would include CMA or CGA. University certificates are also becoming more common ways for people to engage in areas of interest while working full-time. They can be completed with a minimum grade in a series of university courses, and are sometimes taken as a way to further one's professional career (either by requirement or choice). They are gaining credence and ground in both the academic world and the working world.
See also 
- "Maryland State Department of Education High School Graduation Question and Answers" (PDF). Montgomery County Public Schools.