The Best Free Quant Interview Prep Resources (2026)
Free books, firm guides, drills and problem banks for quant interviews, checked in October 2026, with what each covers and where it stops.
You can prepare for a quant interview without paying for anything. The best probability textbook for the job is free to read online. One of the most selective trading firms publishes its own interview guide and a recorded mock interview. The standard arithmetic drill is a free web page. What free material usually lacks is structure and feedback: someone to check your answer, a clock, and a counterparty for the market making round.
This is our list of free resources that are actually worth your time, what each one covers, and where each one stops. We checked every link and every "free" claim in October 2026. Paid tiers change, so if something here has moved behind a paywall since, tell us.
The short answer
If you want a free stack that covers most of a quant interview:
- Jane Street's Probability and Markets guide and mock interview for what a trading interview sounds like.
- Introduction to Probability by Blitzstein and Hwang, free online, with the Stat 110 lectures, for the probability foundation.
- Zetamac for daily arithmetic speed.
- Brainstellar for classic puzzles.
- PuzzledQuant's free tier for graded, firm-tagged interview problems and a daily question.
- LeetCode's free problems if your role has a coding round.
Together those cover the probability, brainteaser, arithmetic and coding rounds. The gap is the market making round, which we come back to below.
Comparison table
| Resource | What it covers | What is free | Main limit |
|---|---|---|---|
| Jane Street guide, mock interview, puzzles | Probability, markets, interview style | All of it | Short; puzzles are harder than interview questions |
| Blitzstein and Hwang, Stat 110 | Probability foundations | Book PDF, lecture videos, edX course | A textbook, not interview practice |
| MIT OCW 18.05 and 6.041 | Probability and statistics courses | Notes, problem sets, solutions, exams | Course pace; no interview framing |
| Probability cheatsheet (Chen, Blitzstein) | Formulas and distributions on 10 pages | Reference only | |
| 3Blue1Brown, Essence of Linear Algebra | Linear algebra intuition | Videos | Intuition, not exercises |
| Zetamac | Arithmetic speed | Fully free | Arithmetic only; scoring differs from real tests |
| Brainstellar | Classic puzzles by difficulty | Fully free | No grading or tracking |
| PuzzledQuant free tier | Graded problems, daily question, Arithmatic Mania game, sample C++ and OCaml | 560+ problems and more | Premium problems, the other games and videos are paid |
| QuantGuide Basic | Probability and brainteaser questions | A free tier with some questions | Full solutions, hints and company search are premium |
| LeetCode | Coding rounds | Most problems | No quant content; company tags are paid |
| OpenQuant | Quant job listings | Job board | Little practice material |
Free material from the firms themselves
Start here. Firm material is written by the people who will interview you, and most candidates never read it.
Jane Street publishes the most. Its trading interviews page describes the process: phone interviews first, then in-person interviews that "may include problem solving, probability and statistics, coding (in any language of your choice), data analysis, and general interests." The same page hosts a recorded mock interview with a narrated timeline. Watch it for how much the candidate talks and how they handle hints. The Probability and Markets PDF covers the concepts its trading questions are built on, and the puzzles page posts a new puzzle every month or two. The puzzles are much harder than interview questions. Treat them as a test of taste, not as prep volume. We cover the firm in detail in our Jane Street interview guide.
Optiver has a career hub with recruiting FAQs by region, intern stories, and interview tips for software engineers. It is less of a study guide than Jane Street's material, but it is the right place to check what the current process looks like. Our Optiver guide covers the 80 in 8 arithmetic test and the rest of the loop.
Other firms publish less, but almost all have a careers FAQ. Read it before you apply. It tells you how many rounds to expect, and sometimes which language you can code in.
Free probability and math foundations
Introduction to Probability by Joe Blitzstein and Jessica Hwang is the textbook from Harvard's Stat 110. The course site links a free online version of the second edition, the lecture videos on YouTube, and a free edX course, Stat110x. If you only use one free resource for probability, use this one. Its "story" approach to distributions and its emphasis on conditioning are exactly what interview problems reward. When a terse green book solution makes no sense, the missing idea is usually explained here. Our review of the best quant interview books explains how it fits next to the green book.
The probability cheatsheet by William Chen and Joe Blitzstein is a 10-page summary of the Stat 110 material: formulas, distributions, and short worked examples. It is useful for review the week before an interview. It will not teach you anything you have not already learned.
MIT 18.05, Introduction to Probability and Statistics on MIT OpenCourseWare covers combinatorics, random variables, distributions, Bayesian inference, hypothesis testing, confidence intervals and regression. It includes problem sets and exams with solutions, and an interactive version on MIT's Open Learning Library. It is a good choice for research candidates who need the statistics half as well as the probability half.
MIT 6.041, Probabilistic Systems Analysis is the more rigorous probability course, with lecture videos and problem sets. It is useful if 18.05 feels too gentle.
3Blue1Brown's Essence of Linear Algebra builds geometric intuition for vectors, matrices and eigenvalues. Research interviews sometimes ask for exactly that intuition, and these videos are the fastest free way to get it.
The limit of all of these is the same: they teach the math, not the interview. None of them is timed, none checks your answers in the moment, and none tells you which questions firms ask. Use them to fix gaps, then move to interview-style practice.
Free interview practice
Zetamac is a configurable arithmetic sprint. The default game gives you two minutes of addition, subtraction, multiplication and division. Ten minutes a day for a month makes a visible difference. Its limit is that real screens are scored differently. Optiver's 80 in 8 is commonly reported to take a point off for a wrong answer, which Zetamac never does, so your Zetamac habit of always answering does not carry over. Our guide to mental math for quant interviews covers the techniques and the skip discipline.
Brainstellar has a long list of classic puzzles in albums: easy, medium, hard, probability, discrete maths, strategy and general tricks. Many interview questions are variants of these. The explanations are step by step but brief, and there is no grading or progress tracking. One puzzle a day is a good habit early on. Our quant brainteasers guide covers the patterns behind the classics.
LeetCode has most of its problems free. That covers the algorithm rounds in developer and many researcher loops. It has no probability, market making or arithmetic content, and its company tags are behind its premium plan.
QuantGuide has a free Basic tier with part of its question bank. Its pricing page lists premium questions, hints and detailed solutions for every question, and search by company as premium features. It also has a speed arithmetic game called Quantify. The free tier is a reasonable sample. Expect to hit the paywall when you want a full solution or a company filter. We compare it with other options in QuantGuide alternatives.
OpenQuant is a free quant job board, with salary ranges on many listings. It has little practice material.
Forums. Reddit's r/quant and the QuantNet forums have interview reports and advice threads. They are free and sometimes very useful. They are also unverified: a confident post about a firm's process may be three years old or wrong. Cross-check anything important against the firm's own pages.
What PuzzledQuant gives you for free
We built PuzzledQuant for this, so here is exactly what the free tier includes and what it does not.
Free:
- 560+ graded problems across probability, expected value, brain teasers, combinatorics, statistics and more. You submit an answer and it is graded on the spot.
- Firm tags. Problems are tagged with the firms known to ask them, and you can browse by firm, for example Jane Street or Citadel.
- The question of the day, one new problem every day.
- Sample C++ and OCaml exercises.
- Learning resources, real quant resumes from people who landed offers, the job board and the discussion forum.
- The MCP server, so ChatGPT or Claude can pull the free problems and grade your answers. See preparing with AI.
Not free: the 590+ premium problems (their titles are visible, the statements are not), premium games such as 80 in 8 and the Dice Market Maker, the full C++ and OCaml exercise sets, video walkthroughs, the Top Interview Questions playlist, and Problem Sets. Premium is $35 a month, $60 a quarter or $150 a year. See pricing.
The honest summary: the free tier is enough to practise the probability and brainteaser rounds with real grading for weeks. It is not enough to rehearse the market making round or to drill the 80 in 8 format specifically.
The gap free resources leave
Free material covers the math well. It covers the formats badly.
- Market making and betting rounds need a counterparty who trades against your quote. No free textbook does that. Free options: read our market making games guide, then practise with a friend. One person deals hidden cards, the other quotes a bid and an ask. It is awkward for ten minutes and then very useful.
- Negatively marked arithmetic screens need practice with the same rule. Run Zetamac, but before each answer ask yourself whether you would skip it on the real test.
- Estimation questions need calibration feedback. Our Fermi estimation guide shows how to score your own intervals.
- Firm-specific style comes from firm material and tagged problems, not from general textbooks.
A free eight-week plan
| Weeks | Do this | Free resources |
|---|---|---|
| 1 to 2 | Fill probability gaps: conditioning, expectation, common distributions | Blitzstein and Hwang, Stat 110 lectures |
| 1 to 8 | Ten minutes of arithmetic a day | Zetamac |
| 3 to 5 | Interview problems by topic, answers checked | PuzzledQuant free problems, Brainstellar |
| 5 to 6 | Market making and estimation formats | Our guides, live practice with a friend |
| 6 to 7 | Coding round, if your role has one | LeetCode free problems |
| 7 to 8 | Firm-specific: firm pages, tagged problems, mock interview out loud | Jane Street material, firm careers pages, firm problem pages |
For a fuller schedule, including 4- and 12-week versions and how the plan changes for traders, researchers and developers, see how to prepare for quant interviews. If you are still at university, quant interview prep for students covers the timeline.
Frequently asked questions
Can I prepare for quant interviews for free?
Yes, for most rounds. Blitzstein and Hwang's probability book and the Stat 110 lectures are free, Jane Street publishes a free probability guide and mock interview, Zetamac and Brainstellar are free, LeetCode's main problem set is free, and PuzzledQuant's free tier has graded, firm-tagged problems. The hardest round to prepare for free is market making, which needs a counterparty.
What is the best free probability resource for quant interviews?
Introduction to Probability by Joe Blitzstein and Jessica Hwang, from Harvard's Stat 110. A free online version of the second edition is available, along with the course's lecture videos and a free edX course. Pair it with interview-style problems, because a textbook does not teach interview formats.
Is Jane Street's interview guide free?
Yes. Jane Street publishes its Probability and Markets guide as a free PDF, a recorded mock interview and a description of its trading interview process on its website, and it posts a new puzzle every month or two.
What does PuzzledQuant's free plan include?
560+ graded problems, firm tags, the question of the day, sample C++ and OCaml exercises, learning resources, resumes, the job board, discussions and the MCP server. Premium problems, premium games such as 80 in 8, the full exercise sets and video walkthroughs are paid.
Is Zetamac good preparation for Optiver's 80 in 8?
It is good for raw speed. It does not copy the format: Optiver's test is commonly reported as 80 questions in 8 minutes with a point deducted for each wrong answer, so you also need to practise skipping questions you cannot finish quickly.