Would getting an undergrad degree in mathematics hurt my chances of of getting into a CS PHD program? Are there statistics on admissions rate by major online?

Edit: in the us

  • This might depend a bit on where. What country?
    – Buffy
    Aug 22, 2021 at 16:10
  • My bad : United States
    – Tejas Rao
    Aug 22, 2021 at 16:10
  • If you intend to go into theoretical CS, I would think mathematics could be more useful than a CS degree if it doesn't have a strong focus on theory.
    – kaya3
    Aug 23, 2021 at 10:02
  • Hurt maybe, but you can probably still get in. I did a BS in math, MS in Electrical and currently a PhD in CS which I am working on exiting. Probably change to CS is easier than Electrical which can have a more physics focus. Aug 23, 2021 at 20:06
  • Wouldn't hurt your chance at all ! I know so many awesome CS people all have a math or physics undergrad degree. So go for it Aug 24, 2021 at 5:11

3 Answers 3


I doubt the statistics would help you much. But a switch from math to CS is possible with just a BS/BA. You will have time to catch up on some things.

I'll assume that you can program, but you probably want to take a few electives in CS if they are open to you. Data Structures and Algorithms is the most important but a couple of additional theoretical courses would help. Database Theory, Operating Systems, for example.

And look to getting good letters of recommendation from both math and CS professors.

Double majors are a possibility in some places, but a math major with a CS minor would probably give you everything essential.

Note that both math and CS are a lot about abstraction. The mathematical way of thinking is a benefit in CS.


I know several people who have been admitted into strong CS PhD programs with only undergraduate training in math. Don't accept this answer as I don't have numbers/statistic to back it up, but qualitatively I will say the following:

If you are pursuing theoretical computer science, math is definitely an acceptable undergrad to come from (maybe even preferred in some departments). Obviously it helps to have more discrete mathematical courses and things closer to TCS (ex: automata theory, complexity theory, algorithms etc...)

If (and I doubt this is the case but I dont want to make assumptions) you are interested in entering the applied side of things, you will probably hurt your chances if only carrying mathematical training. Math classes will teach you to handle proofs and be creative with abstract thinking. They will not teach you how to work comfortably with systems programming, or architect software well, or build effective distributed systems Etc... and any competent applied CS researcher knows this. That said you can always start trying to acquire this experience (maybe even do some research as an undergrad in an REU or similar program) to beef up you application.

There's also no hard requirement to start a PhD immediately after graduating undergrad. Take a year or 2 or 10 if thats what you need to make the transition.


Mathematics knowledge is very useful in many areas such as machine learning, pattern recognition, artificial intelligence, etc. Especially for basic scientific work. There may be differences according to countries, universities, institutes. For this reason, you can increase your chances by carefully examining the required skills in the applications and by correspondence with the advisors.

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