Guesstimates: Why, What & How?

Sanyam Aggarwal
4 min readAug 20, 2023


If you’ve ever been advised by a senior who recently secured their Non-Tech placement, chances are they stressed the importance of guesstimates during interviews. Blindly following their recommendation, we diligently tackle these puzzles without understanding — Why they hold such significance. Let’s explore their true value.

Guesstimates are used as a part of interviews to warm up a candidate. Interviewers test the quantitative ability, numerical thinking & judgment capabilities in an individual through such problem statements.

What Guesstimates actually are?

Guess + Estimate, Yes Guesstimates are rough estimates, quick calculations made in situations with limited data. The type of statement can feel unsettling at first. But, there isn’t such a right or wrong answer to them. For example, Estimate the number of Uber Drivers or say Estimate the number of schools in Delhi, feels weird right?

However, the interesting aspect is that it’s conceivable that even the interviewer themselves may not possess the actual answer to the problem. This is because guesstimates rely on a combination of intuition, past experiences, general knowledge, and mathematical calculations to arrive at an informed estimation of a result.

Jumping to the part for which most of you are here.

How to solve Guesstimates?

What holds the greatest importance in tackling Guesstimates?

The answer is just one word, Approach. Yes, you’ve read it right, here your journey matters more than the final destination.

While you may find Guesstimates easy to handle, it is essential to bear in mind that becoming proficient in solving them requires extensive practice. See whenever you will encounter one, you’ll realise that the problem statement in itself is vague or unclear, you can’t start solving right after hearing it and even it’s prescribed to not to do that. Solving a Guesstimate like a pro has a proper flow, it’s basically a 5 Step Process

Step 1: Ask logical clarifying questions.

By asking relevant questions, you can gather additional details or specifications that will help refine your approach and improve the accuracy of your estimation. Effective questioning enables you to better understand the problem, identify relevant variables, and make more informed assumptions, leading to a more accurate guesstimate.

Step 2: List down all your assumptions with reasons clearly to the interviewer.

This helps to build a solid foundation for your guesstimate, showcasing your analytical thinking and ensuring a transparent and effective communication process with the interviewer.

Step 3: Structuring the Approach

Make sure your approach is as MECE as possible. MECE — Mutually Exclusive Collectively Exhaustive, for example: Dividing Profits in terms of Revenue minus Costs. They both are mutually exclusive i.e. Non overlapping and at the same time Collectively Exhaustive i.e. Clearly defining the Profits.

Step 4: Performing Calculations

Here you are required to perform mathematical calculations without the aid of calculators. However, you can utilise the technique of rounding off to simplify the calculations. For instance, we know that the area of Delhi is 1483 sq Km, but you can round it off to 1500 sq Km for ease of computation.

Step 5: Sanity Check

This involves evaluating whether the estimated value aligns with common sense, known facts, or benchmarks. It helps you identify any potential errors, unrealistic assumptions, or major discrepancies in your estimation. By conducting a sanity check, you ensure that your estimation falls within a reasonable range and is logical in the given context.

Remember, practice and experience are key to improving your guesstimate-solving skills. The more you engage with different guesstimate problems, the better you become at making accurate estimations and effectively communicating your thought process.

In our next article, get ready to dive into the fascinating world of Guesstimates as we explore real-life examples and solve them using various approaches. Stay tuned as we unlock the secrets to mastering these mind-boggling puzzles. Until then, let curiosity be your guide and let the adventure begin!

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Sanyam Aggarwal

Data and Product Enthusiast | Follow Me 🫶 to Conquer the Art of solving Guesstimates