The usual summary of the GS-1320 chemist requirements is “30 hours of chemistry,” a shorthand that is not OPM’s wording. OPM’s text asks for three things, not one: 30 semester hours of chemistry, mathematics through differential and integral calculus, and at least 6 semester hours of physics. Most short summaries drop the last two. This guide sets out what OPM prints, then shows where PrereqCourses can help and where it cannot. The catalog covers only part of this requirement, and no course here completes a qualification. OPM pages were read on October 25, 2026.
Please read first: This page explains published OPM standards. OPM and the hiring agency’s HR office decide whether coursework qualifies. Upper Iowa University issues the credit. PrereqCourses does not issue credit, and nothing here promises acceptance, a job offer, or credit transfer.
Table of contents
GS-1320 chemist requirements: what OPM prints
GS-1320 is the Chemistry Series. Here is the first route on OPM’s Chemistry Series 1320 page (retrieved October 25, 2026):
“Degree: physical sciences, life sciences, or engineering that included 30 semester hours in chemistry, supplemented by course work in mathematics through differential and integral calculus, and at least 6 semester hours of physics.”
The second route starts with the words “Combination of education and experience” and then continues with this text from the same page:
“course work equivalent to a major as shown in A above, including at least 30 semester hours in chemistry, supplemented by mathematics through differential and integral calculus, and at least 6 semester hours of physics, plus appropriate experience or additional education.”
Every time the 30 hours come up, three parts come with them:
- 30 semester hours in chemistry. OPM prints the count.
- Mathematics through differential and integral calculus. OPM prints no hour count for the math, only the level.
- At least 6 semester hours of physics. OPM prints only “at least 6 semester hours of physics.” It does not say whether calculus is required or whether the physics must be at a major level.
The hours sit inside a degree, or inside course work equivalent to a major plus experience or more education. They are not a stand-alone route. A person with 30 chemistry hours and nothing else in the picture does not meet the text, and a person with a degree in a listed field still has to show all three parts.
Notice the field list in the first route. OPM names physical sciences, life sciences and engineering. It does not name chemistry as the degree field, and it does not say which of those degrees HR should prefer. The 30 hours are the content OPM wants included, whatever the major is called. That is why a biology, environmental science or engineering graduate can read the same page as a chemistry graduate and still need to count carefully.
OPM also says the series uses its Group Coverage Qualification Standard for Professional and Scientific Positions alongside the page above. The GS-1320 chemist requirements are therefore the series page plus that group standard, read by the hiring agency’s HR office.
Why the 24-hour fallback does not apply here
You may have seen “24 semester hours” in federal job talk, especially for the biologist series. That number comes from the group standard, and it only applies when a series page prints no count. The sentence reads, from the group standard (retrieved October 25, 2026): “Where specific course requirements are not indicated in paragraph A, the number of semester hours required to constitute a major field of study is the amount specified by the college or university attended. If this number cannot be obtained, 24 semester hours will be considered as equivalent to a major field of study.”
GS-1320 does print specific course requirements, starting with 30 hours of chemistry. The fallback is not needed, so do not confuse this series with GS-0401. Our guide to GS-0401 requirements covers that one separately.
What PrereqCourses can cover and what it cannot
This page is plain about it: the PrereqCourses catalog covers part of the requirement and not all of it. The table lines up each part of the GS-1320 chemist requirements with the live catalog. Prices were read from each live product page on October 25, 2026. Textbooks and lab materials are purchased separately.
| OPM part |
What the catalog has |
What it does not have |
| 30 semester hours in chemistry |
CHEM 151 and CHEM 152 General Chemistry I and II w/ Lab, 4 hours each, $695 each. CHEM 251 and CHEM 252 Organic Chemistry I and II w/ Lab, 4 hours each, $695 each. CHEM 330 and CHEM 331 Biochemistry I and II, 3 hours each, $675 each. That is 22 hours if HR counts both biochemistry courses as chemistry, and 16 hours if it does not. |
At least 8 hours short of 30, or 14 short if biochemistry is not counted. No analytical chemistry, physical chemistry, inorganic chemistry or instrumental analysis course. |
| Mathematics through differential and integral calculus |
MATH 120 Calculus I, 3 hours, $675. Its page says it is “the first of four courses” and “focuses on differentiation of all elementary and trigonometric functions, including parametric and polar functions.” |
No integral calculus course. No Calculus II or later. MATH 105 College Mathematics and MATH 107 College Algebra are not calculus courses. |
| At least 6 semester hours of physics |
PHY 115 and PHY 116 Introduction to Physics I and II w/ Lab, 4 hours each, $695 each. That is 8 hours in total. |
Our physics courses are trigonometry-based, not calculus-based. OPM prints only “at least 6 semester hours of physics” and does not say whether calculus is required. HR decides whether it meets OPM’s 6-hour physics requirement. |
The table is a map of the catalog, not a plan. Someone with a biology degree and two semesters of general chemistry would count those 8 hours first, then compare the other parts. Someone with a chemistry degree who is missing only integral calculus would see in the table that the catalog cannot help with that part at all. Reading the GS-1320 chemist requirements this way keeps the focus on gaps rather than on buying courses.
What PrereqCourses does not offer
PrereqCourses does not offer the integral calculus or the remaining chemistry hours. These courses cannot complete the GS-1320 requirement on their own. Our physics courses are trigonometry-based, not calculus-based. Even if HR counts both biochemistry courses, the chemistry is short by 8 hours (14 if HR does not), and the calculus part stays incomplete.
Biochemistry deserves a word. CHEM 330 and CHEM 331 are biochemistry courses taught under the CHEM prefix. OPM does not say whether biochemistry counts as chemistry for this series, so that is HR’s call. For course content, see our guides to a chemistry online course, organic chemistry online, a biochemistry online course, an online physics course and a calculus online course.
Here is one example of the arithmetic, not a recommendation. All six chemistry courses (22 hours and $4,130 if HR counts both biochemistry courses as chemistry, 16 hours and $2,780 if not), PHY 115 and PHY 116 (8 hours, $1,390) and MATH 120 (3 hours, $675) come to 33 semester hours and $6,195 with biochemistry counted, or 27 hours and $4,845 without it, at October 25, 2026 prices. Those are the hours the catalog can supply toward three of the parts. None of it closes the remaining gap, and none of it tells you what HR will count.
Courses are self-paced and fully online. They begin on the 1st of each month, and you have 6 months to finish, with the first assignment due within 2 months. Each has one final exam.
Upper Iowa University (UIU) is accredited by the Higher Learning Commission (hlcommission.org), an institutional accreditor recognized by the U.S. Department of Education. OPM asks that education come from an institution accredited by an accrediting body recognized by the U.S. Department of Education, and OPM and the hiring agency’s HR office decide whether coursework qualifies, so confirm with the announcement.
Reading your own transcript against the three parts
Before reading any announcement closely, check your own record against the GS-1320 chemist requirements. A short self-check tells you more than any summary. Open your transcript and make three lists.
- Chemistry hours. Count general, organic, analytical, physical, inorganic and biochemistry courses separately. Keep a running total, and keep the biochemistry hours in their own line, since HR may treat them differently.
- Calculus courses by level. Write down each course that includes differentiation and each that includes integration. OPM’s phrase is “differential and integral calculus,” so both halves matter.
- Physics courses. Write down each course and its credit hours. Check the hours, not just the titles.
Two more points help. First, the group standard quoted above says the hours for a major are “the amount specified by the college or university attended” when a series page gives no specific requirements. GS-1320 does give specific requirements, so that sentence is not the test here. Still, your school’s own chemistry major list shows how that school sorts courses, and it can help when you talk to HR.
Second, OPM’s qualification policies (retrieved October 25, 2026) say: “Additional credit cannot be given for duplicate course work.” If two courses cover the same material, you will not get credit twice, so do not stack overlapping classes to reach 30.
Questions to put to HR
Questions work better than assumptions here. Put these questions about the GS-1320 chemist requirements to the contact listed on the announcement before you spend money on anything.
- Does biochemistry count as chemistry for this announcement?
- Does an introductory physics sequence meet the 6 hours, or does the announcement want something more advanced?
- How do you read “mathematics through differential and integral calculus,” and is there a level or course list you apply?
- Does a partial set of courses help my application, or does it only matter when it completes a path?
Those are questions, not answers. OPM and the hiring agency’s HR office decide whether coursework qualifies, and the answer can differ by agency and by announcement.
Accreditation, online credit and transcripts
OPM’s policy page says: “Correspondence or distance learning course work is also acceptable if the applicable school within the institution or applicable curriculum is accredited by an accrediting body that is recognized by the Secretary of the U.S. Department of Education. The distance learning courses should indicate the credit hours for each course and be indicated on the degree transcript together with traditional course work and credits.”
The second sentence is about how credit appears on a transcript. If your degree is from another school, ask HR how they treat credit that appears on a separate UIU transcript.
OPM also says: “It is the applicant’s responsibility to provide documentation or proof that he or she has met the applicable educational provisions described in this subsection.” An official UIU transcript costs $10 per copy, per our FAQ. You can read more on our page about Upper Iowa University. Courses are taught and credited by Upper Iowa University, accredited by the Higher Learning Commission.
Quarter hours. OPM prints that “30 semester hours or 45 quarter hours is comparable to 1 year of undergraduate education.” Worked out from those two figures, a quarter hour is about two thirds of a semester hour. OPM does not print that conversion, so treat it as arithmetic and ask HR how they convert.
Steps before you apply
- Read the education section of the announcement, not a summary of it. Note whether it repeats all three parts.
- Match your transcript to the three parts. Use the lists above and mark where you are short.
- Ask HR the questions in the section above.
- Fill gaps last, and only if the answer shows one. A course helps only if HR counts it.
PrereqCourses offers a free advisory session for planning prerequisite coursework. It is not an OPM or HR service, and it does not decide whether coursework qualifies.
For the same rules across nine federal series, see OPM semester hour requirements by series. For other series, see our guides to consumer safety officer requirements and correctional treatment specialist requirements. If you are comparing courses by subject, start with our online chemistry courses, physics courses and math courses pages.
Frequently asked questions
How many semester hours of chemistry does a GS-1320 chemist need?
For the GS-1320 chemist requirements, OPM prints 30 semester hours in chemistry. That figure comes with mathematics through differential and integral calculus and at least 6 semester hours of physics, inside a degree or an equivalent combination.
Does biochemistry count toward the GS-1320 chemist requirements?
OPM does not say. Biochemistry courses at PrereqCourses are taught under the CHEM prefix, but HR decides whether they count toward the 30 hours.
Can I meet the GS-1320 chemist requirements with hours alone?
No. The hours sit inside a degree in a listed field, or inside course work equivalent to a major plus experience or additional education.
Do online courses count toward the GS-1320 chemist requirements?
OPM says distance learning course work is acceptable if the school or curriculum is accredited by a body recognized by the U.S. Department of Education, and that credit hours should appear on the degree transcript with traditional course work. OPM and the hiring agency’s HR office decide whether coursework qualifies.
Where this leaves you
The GS-1320 chemist requirements are three parts, not a single number: 30 semester hours of chemistry, mathematics through differential and integral calculus, and at least 6 semester hours of physics. The PrereqCourses catalog has up to 22 chemistry hours (16 if HR does not count biochemistry), Calculus I and two physics courses. It has no integral calculus and not enough chemistry, so it covers part of the requirement and cannot complete it. Count your own hours, ask HR how they read the three parts, and then decide whether a course fills a real gap.
If it does, browse our online chemistry courses or our guide to accredited online prerequisite courses. For the same rules across other series, see OPM semester hour requirements by series.
This page explains published OPM standards, retrieved October 25, 2026. OPM and the hiring agency’s HR office decide whether coursework qualifies. Upper Iowa University issues the credit. PrereqCourses does not issue credit, and nothing here promises acceptance, a job offer, or credit transfer.
