How do I prepare for investment banking interviews for free?

Start with free explanations, answer questions without notes, and use IB Offer's free access to test your reasoning. Add peer mock interviews and employer research. A useful free preparation plan has outputs: answers you have attempted, mistakes you have corrected, and a role you can explain.

IB Offer publishes this guide and recommends its own practice tools. Free access has limits, which we spell out below.

What can you use without paying?

Wall Street Oasis publishes a public interview-question guide. Use public materials from their legitimate publishers. If you are weighing their paid offering against coached practice, see our IB Offer vs Wall Street Oasis comparison. A download offered by a stranger is not evidence that paid material is authorised for redistribution.

What is free on IB Offer?

As checked on 6 September 2026, no card is required for free signup. Free accounts receive five graded reps per day during the first three days from their first graded rep, five Ask IB messages per day, and unlimited Mental Math. The graded allowance is a short window, not five graded answers every day forever. Review the current access terms on IB Offer.

Use that window deliberately. Before starting your first graded rep, collect a short list of concepts you want to test. After each response, write down the specific correction. Avoid using all your attempts to repeat an answer you already know.

After the three-day graded window, the published free plan still includes unlimited Mental Math and five Ask IB messages per day. Do not schedule ongoing free AI grading beyond that window. Check the Help Center for current terms.

Start with a public accounting question, a DCF question, or the investment banking technicals flashcards before spending any of the limited graded window.

What should a seven-day free plan produce?

This is a suggested sequence, not a claim that seven days makes every candidate ready. Move slower when a concept is new. Start the graded window only when you are ready to attempt the topics you have selected.

The graded window runs from the first graded rep; your account timing governs access, not the labels in this table. Use public guides and peer feedback whenever graded access is unavailable.

What should a free study session look like?

Here is an original 30-minute routine. The timing is a suggestion, not a validated preparation threshold.

Minutes 0 to 8: learn. Read one focused explanation, such as how a DCF works. Write down its purpose and the main steps.

Minutes 8 to 15: retrieve. Close the explanation. Answer the question in your own words. If you get stuck, note exactly where before reopening the source.

Minutes 15 to 23: correct. Check your answer against the explanation or available feedback. Repair one error. For example, distinguish the value of operations from the amount attributable to shareholders.

Minutes 23 to 30: transfer. Explain the same concept with a different example, then say it aloud. Changing the example helps reveal whether you understood the reasoning or remembered a sentence.

Open technical practice when you are ready to attempt an answer.

Can you apply the idea after closing the guide?

Try this original exercise before opening the answer: a simplified business has enterprise value of 150, debt of 40, and excess cash of 10. There are no other claims or adjustments. What is equity value? What happens if it borrows 5 and leaves all the proceeds as additional excess cash, with enterprise value unchanged?

Check the bridge and the changed case

Equity value starts at 120: 150 minus 40 plus 10. After the borrowing, it is still 120: 150 minus 45 plus 15. Debt and excess cash rise by the same amount. Under these stated assumptions, the two bridge adjustments offset. Do not assume debt always leaves equity value unchanged if the proceeds are spent or enterprise value changes.

If you got the number but cannot explain the offset, revisit the enterprise-value bridge. Explain it aloud with new numbers. Roediger and Karpicke's experiments found benefits for delayed recall from retrieval practice with prose passages. That supports trying to recall an explanation; it does not validate this plan or predict interview outcomes.

The article's graded rep is separate from this fixed self-check and can be attempted before signup, subject to its public usage limit. Use any available feedback to identify one correction, then verify the underlying reasoning.

If you want another no-account rep, try the public DCF practice page. When you want to keep a graded attempt and continue the feedback loop, create a free IB Offer account.

How can you practise behavioral answers without a coach?

Ask a peer to choose a question from our behavioral interview guide. You can also try a public behavioral question before asking someone else to review your answer. Give them permission to interrupt vague claims.

If you say you led a team, they should ask what you personally decided. If you claim an improvement, they should ask how you know it happened. Record the exchange and listen for the point at which the answer stops addressing the question.

A peer may not be qualified to judge advanced technical content. Use credible technical sources for that part. Use the peer to test whether your explanation is understandable and supported.

Check your university's career service too. Illinois describes a mock-interview service; eligibility and booking rules depend on your institution. Do not assume the reviewer will be a finance specialist.

How do you choose a credible free source?

Look for an identifiable publisher, worked reasoning, and links supporting date-sensitive claims. Check whether a firm-specific process statement applies to your programme and location. Treat an anonymous question list as a starting point to verify, not proof of what your interviewer will ask.

A free page should teach enough for you to explain an answer and check a variation. A long question count cannot show that by itself. Keep one main reference and a mistake log instead of collecting overlapping lists.

When is paying worth considering?

Pay when you can name the missing resource: more graded practice, structured spreadsheet teaching, or feedback from a qualified person. First check whether your school or employer already provides access. More material is useful only when you will use it to resolve a gap.

Use our course-value decision guide to test that purchase. For the broader study sequence, read how to prepare for investment banking interviews. When free stops being enough, compare paid paths in IB Offer versus the 400-questions guide.

Frequently asked questions

Can I prepare without buying a course?

You can build a substantial preparation routine with public resources and peers. Whether you need more support depends on your starting knowledge, target role, and ability to evaluate your work.

Is all IB Offer practice unlimited for free?

No. Mental Math is unlimited under the published free plan; graded reps have the three-day allowance described above. Check current terms before planning around access.

How this guide was prepared

The IB Offer editorial team reviewed relevant competitor coverage and checked the official sources linked here on 6 September 2026. Recommendations reflect preparation tasks and published product scope. The exercises and prompts are original examples. We did not conduct a controlled product or hiring-outcome study.

Sources

IB Offer access terms and Wall Street Oasis public interview guide, checked 6 September 2026. The session plan is original editorial guidance.