In physics and astronomy PhD programs, the department typically covers tuition and related expenses for its graduate students, or the university waives these expenses. Most students never see a bill—or if they do, it has a zero balance.
To cover the cost of living, graduate students typically earn a stipend—a fixed amount paid as a salary. The typical stipend is less than what you might earn in the workforce, but it offers some breathing room along the way to a PhD. Stipends can be paid by the university through teaching or research assistantships, or paid by the department or an external source through a fellowship.

Teaching assistants (TAs)

Universities fund TA positions to facilitate their undergraduate classes. TAs are usually assigned to work with an undergraduate course in their department. They may be responsible for leading discussion or problem sessions, teaching labs, holding office hours, grading homework, and proctoring exams, among other activities. It’s common to spend about 20 hours each week on TA duties.

In most physics PhD programs in the United States, first-year students receive teaching assistantships unless they’ve already lined up a research assistantship or fellowship, are not proficient in speaking English, or decline financial assistance.Students may continue to work as a TA in later years if they don’t have research funding or simply wish to continue teaching. Some astronomy PhD programs follow a similar model, while others have students begin research immediately and TA in later semesters.

Research assistants (RAs)

RAs get paid for doing research. RA positions are typically funded by individual labs and sometimes by the department. They enable students to focus on doing research toward their thesis. Money for RAs often comes from research grants, so the number of positions in a particular lab often depends on its current funding situation. RAs may get paid a little more than TAs. Some programs, especially astronomy programs, may help you line up an RA before you start. Physics programs will often let you come in as an RA if you’ve worked out the details with a researcher in advance.

Fellowships

Graduate students supported by fellowships receive a stipend that isn’t tied to teaching or research in a particular lab. Fellowships can be for one or more years. Students entering a program with a fellowship can typically spend more time on their coursework during the first two years since they don’t have to be a TA or RA. Fellowships also give students more flexibility in their research, as they can work in a lab without needing financial support from that lab. National fellowships are offered by foundations, nonprofits, corporations, and government agencies. Many follow the awardee to whatever school they choose and if they transfer programs. Fellowships are competitive, and application deadlines for incoming grad students can be up to a year before you even start a program. It’s never too early to start looking. Some departments provide internal fellowships as well.

A PhD can take many years to complete, so it’s essential to consider the financial aspects of this path. When comparing stipends for different programs, be sure to factor in the local cost of living and healthcare. Virtually all programs offer graduate students healthcare plans, but coverage and costs can differ significantly. Extras such as transportation assistance, access to staff daycare facilities, or affordable graduate student housing options can also reduce your living expenses.
Don’t let low stipends limit your options right from the start. Apply to higher-paying fellowships and reach out to departments of interest—if you’re a good fit, they may be able to help you secure a grant or fellowship that can make all the difference.

This article is adapted from an earlier version that appeared in the 2022 issue of GradSchoolShopper magazine.

Caveats and Considerations

• US PhD programs in many other scientific disciplines have a similar approach to supporting grad students, but the amount and number of stipends vary with research funding and other factors.
• Some financial support—even in physics and astronomy PhD programs—may be available to US citizens only.
• Look carefully at the financial support packages typically offered by any program that interests you, and read the fine print in any offers you receive.

 “A big part of what my National Science Foundation (NSF) fellowship did for me was give me freedom. It made me feel like it wasn't required of me to do everything that was asked of me by my advisor and by the institution because they were no longer paying me. I was getting paid by the NSF, and if I picked up and left, the NSF was still going to pay me. Finding my own funding was so empowering for me.”

—Simone Hyater-Adams, Founder, MEGA Imagination LLC