Resources for market sizing drills with complete answer?

Hi there,

If you’re specifically looking for market sizing drills with full, well explained answers, you’re already on the right track.

Personally, I also recommend CraftingCases as the strongest starting point. The market sizing exercises there are realistic, cover a wide range of industries, and the solutions actually explain the logic step by step instead of just giving a number. That’s exactly what you want for interviews.

Beyond that, a few solid additions:

CaseCoach is worth trying if you want more volume. Their market sizing drills are structured and consistent, although some solutions are a bit more “formulaic” and less discussion based than CraftingCases. Still useful for repetition and speed.

Victor Cheng’s market sizing videos and drills are good for learning clean approaches and sanity checks. Less variety, but very strong fundamentals.

BCG Interactive Case examples and older MBA casebooks can be surprisingly helpful for market sizing practice. You won’t always get perfect solutions, but forcing yourself to benchmark and sense check your answers is part of the training.

One practical tip: once you’ve done most written drills, start creating your own market sizings from real life. For example size contactless payments in your city or EV chargers in a country. Write your approach, calculate, then sanity check against public data. That’s very close to interview reality.

If you’ve already done most of CraftingCases, you’re likely at the point where how you structure and communicate matters more than finding new question types. That’s usually where candidates benefit from targeted feedback rather than more drills.

That is a smart pivot. Practicing pure market sizing is often overlooked, but it's a huge component of the early interview rounds—recruiters use it to test how quickly you establish a logical structure and handle assumptions under pressure.

Here is the reality check: you don't need a massive bank of market sizing problems. Once you've done 15-20 solid, varied drills, the key is not seeing new scenarios but mastering how to adapt the core structures (e.g., demand-side penetration, supply-side capacity, proxy/anchor method) to any absurd topic. If you can size the annual revenue of a specific McDonald's store, you can size the market for electric scooters in Southeast Asia.

For dedicated resources, Case Coach is indeed excellent for its highly structured, concise examples—it teaches the methodology more than just providing answers. A fantastic, overlooked resource is actually the Economist's "The World in..." annual publication or similar analyst reports. Take a real-world, obscure product mentioned (say, autonomous underwater vehicles) and force yourself to size that market using a top-down and a bottom-up approach, referencing real global statistics (GDP per capita, population density) as your core inputs. This develops the skill of making practical assumptions, which is where most candidates fail.

Stop chasing volume and start perfecting your structure. Get fast and clean on the structure, and the number will follow.

All the best!

Hi!

I agree that Crafting Cases is a good place to start for market sizing, especially in the early stages. Since you’ve already gone through most of their exercises, I’d say you’re at the stage where pre-made question banks add diminishing returns.

At this point, I’d suggest shifting your approach slightly:

• Create your own market sizing questions.
  Almost anything around you can be turned into a sizing question (e.g., the number of food delivery riders in a city, or the number of cups of coffee sold in an airport). In interviews, the question will often be unfamiliar anyway, so this approach mimics the real experience more closely.
• Time-box yourself (e.g., 2–3 minutes to structure, 5–7 minutes to solve).
  The goal isn’t to land the “perfect” number. It’s to build a clean, logical structure, make reasonable assumptions, and move confidently from top to bottom.
• Practice articulation, not just thinking.
  Say your answer out loud as if you’re explaining it to an interviewer. This is where many candidates struggle more than with the math itself.
• If possible, do it with a partner.
  Both of you size the same market independently, then present your approach to each other as if it’s an interview. This is very effective because:
  • You practice structuring and communication
  • You see alternative, equally valid approaches
  • You learn how flexible market sizing can be, as long as the logic is sound

You can always sanity-check the final number via Google or ChatGPT, but again, the real focus should be on structure and approach, not the exact answer.

Hope this helps. All the best!

Hello!

I would recommend the following:

• Igotanoffer (21 questions with solutions). This is likely the most comprehensive free list available. it includes 21 cases categorized by difficulty (medium to hard) with full written logic for questions like "how many wine bottles are sold in the u.s.?" or "what is the market size for takeaway coffee in london?"
• Management consulted. Their market sizing guide provides a clear "5-step framework" and includes several practice problems. they focus heavily on the "so what" and executive summary, which aligns with your preference for top-down communication.
• Rocketblocks. While partly paid, their free blog posts offer "full market sizing solutions" that are very technical. they use tables to separate assumptions, calculations, and segmentations, making it easy to see where you might have made a math error.
• Hacking the case interview. This site offers a "cheat sheet" of anchor data (populations, life expectancies, etc.) which is vital for any drill. they provide detailed walkthroughs for classic cases like the number of toothbrushes sold in the u.s. or cars in the u.k.
• Casecoach. their drills are designed to be done on your own, with a clear focus on structuring before you ever touch a calculator

Overall recommendation

• Structure first, math second. Never jump into calculations. for every drill, write out your equation (e.g., $Market Size = Population \times Penetration \times Frequency \times Price$) and confirm the logic before filling in the numbers
• The sanity check. Every complete answer should end with a "gut check." if you calculate the coffee market in new york to be $100 billion, you should immediately recognize that this is too high and re-evaluate your assumptions
• Master the anchor data. You don't need to know everything, but you must know the population of the country you are interviewing in, the number of households, and average income levels. these are the "building blocks" for any market sizing answer