Interviews are designed to comprehensively assess candidates. Such an assessment not only takes into account their accomplishments and personality traits but also focuses on their real-time application of skills. One effective way of putting these skills to the test is by means of guesstimate questions, which have become extremely popular among recruiters.

Guesstimate questions are usually a part of the early rounds of an interview and feature heavily in the consultancy and management sectors, though they can also be asked while applying for roles in other sectors. The main reason for the increase in use of guesstimate questions and answers in recent times is the tendency of guesstimate questions to make candidates think on their feet and demonstrate both theoretical as well as practical intelligence.


  1. What Do Guesstimate Questions Involve?

  2. Steps Involved In Answering Guesstimate Questions

  3. What To Avoid When Tackling Guesstimate Interview Questions

  4. Examples Of Guesstimate Questions And How To Answer Them

  5. Guesstimates At Your Fingertips

What Do Guesstimate Questions Involve?

Guesstimate interview questions involve asking candidates to guess or estimate a number based on limited context and information. Successfully answering guesstimate questions requires interviewees to combine logical thinking, general and background knowledge, mental math and problem-solving skills.

For example, guesstimates for interview can involve questions like, “how many barbers are present in the city of Lucknow?”. There is no one right answer to this question, and neither is a precise answer expected. In answering guesstimate questions, candidates are expected to provide approximate figures that are believable, and more importantly, justifiable through an explanation of the method used to arrive at such a figure. In case your answer to the aforementioned question is 10,000, the answer alone won’t help you in any way. You will need to demonstrate how you arrived at the answer and tell the interviewer why your method is reasonable and trustworthy.

Steps Involved In Answering Guesstimate Questions

Guesstimate questions cannot be solved in one single swoop. It requires patience and the ability to navigate through multiple steps, which are explained as follows:

  1. Ask For Clarifications 

The biggest hurdle while answering guesstimate questions is confusion. So, don’t hesitate to ask your interviewers as many questions as you can to clarify the context of a question. Such clarifications may involve verifying details that you had missed out initially or asking open-ended questions that give you some sort of a hint as to what approach you should take with your answer.

  1. Break Down The Question

Guesstimate questions and answers aren’t meant to be solved in one move or within a few seconds. You’ll  need some time to break the question down into its key components and then rely on your knowledge to make certain predictions. For example, if you’re asked to guess the number of potholes in Mumbai, the first thing you need to know is Mumbai’s population. This is to be followed by giving yourself a rough idea of the number of localities and streets in Mumbai that are metalled, and therefore likely to have potholes. You’ll  then need to figure out how many potholes are usually seen in Indian metropolitan cities across a stretch of two or three miles. Your final answer will be possible only after combining these separate pieces of information by means of the correct mathematical formula.

  1. Justify Your Answer

The third and final part of coming up with guesstimates for interview is providing the reasoning behind your answer. For this, you’re expected to present a clear and coherent line of argument even if it isn’t always the most accurate one. Employers are basically looking to examine your calculation and reasoning skills here, so don’t worry if your method or approach is unconventional. As long as you can justify how and why you arrived at a particular answer, you have nothing to be concerned about.

Following the above steps in the right sequence maximizes your chances to come up with reasonable guesstimates that are taken seriously by your interviewer.

What To Avoid When Tackling Guesstimate Interview Questions

The following things must be diligently avoided while answering guesstimate questions:

  • Try not to rely on your gut feeling while coming up with guesstimates; facts or a credible line of logic are always more reliable

  • When dealing with large numbers, don’t keep fractions or decimals in their original format, but feel free to round them off to the nearest figure

  • Never scribble or try to chalk out your answer on the main sheet provided; always use a rough sheet for such purposes

  • Don’t be thrown off by a seemingly absurd question; no matter how bizarre, there will be a way to answer every question

  • Avoid covering up your shortcomings in calculation or reasoning with complicated language or a false sense of confidence

Examples Of Guesstimate Questions And How To Answer Them

The following examples will give you clear idea of what kind of guesstimate questions to expect during your interviews and how to deal with them:

  1. How Many Tennis Balls Can Fit In A Bus?

This is a classic example of a question that requires clarifications. Firstly, you need to clarify whether the bus is empty or whether it has passengers who are to be accommodated alongside the tennis balls. Secondly, you need to clarify what type of bus is being spoken about—a general single-decker vehicle, a double-decker, an open-top double decker or some other type.

Once you have obtained these clarifications, you can go about answering the question. The first calculation you have to make is to figure out the average volume of a tennis ball. After that you have to estimate the average volume of the bus (keeping in mind the type of bus, and hence, the approximate distribution of seats and whether there are any passengers or not). Finally, you will need to divide the volume of the bus by the average volume of a ball to get your guesstimate.

  1. How Many Refrigerators Are Sold In India Every Year?

For this question the obvious clarification is whether only domestic refrigerators are to be taken into account or whether you should include commercial ones as well. Once you have obtained this clarification, you can proceed with your answer as follows:

Take the overall population of India and roughly calculate the number of households in the country (by dividing overall population by the average size of a household, which is generally taken to be four members). Then, based on your knowledge of household distribution, divide the households into metro or urban (tier 1), peri-urban or suburban (tier 2) and village or rural (tier 3) brackets. Each of these brackets needs to be further broken down based on economic resources into rich, middle class and poor households. After this, you have to estimate the market penetration for each of these economic sections for each bracket.

This is to be followed by calculating the absolute number of refrigerators that are in demand annually—or the market size—by multiplying the sum of penetration with the number of households in each section of each bracket. But this is not all. You also need to factor in that refrigerators are bought either as first-time purchases or as replacements for old refrigerators. So, in order to arrive at the final guesstimate, you need to make two assumptions—the average life of a refrigerator (say 10 years) and the assumed growth rate of refrigerators (say 5 percent). Then the formula by which you’ll arrive at your answer should be:

Refrigerators sold in India in a year = refrigerators sold due to replacement + refrigerators sold due to new growth

Therefore, refrigerators sold in India in a year = (absolute refrigerators in annual demand or market size / average life of a refrigerator) + (growth rate of refrigerators x absolute refrigerators in annual demand or market size)

  1. How Many Square Inches Of Pizza Are Eaten In The United Kingdom Each Month?

For this particular guesstimate question, it may be useful to put actual numbers to the assumptions so as to quantify the guesstimate. The first assumption in order to tackle this question is to estimate the number of pizza eaters in the United Kingdom every year. For such situations, it’s safe and reasonable to assume 50% of the population as the starting figure, which, in this case, provides a figure of 33 million people. Now, it’s time to make another assumption—how many times does an average pizza eater in the UK have pizza per month and how many slices do they consume? You can take the answer to be twice a month and two slices at a time. This makes it four slices a month per person.

If the average slice of pizza is roughly six inches at the base and around 10 inches long, then each slice is equal to 30 square inches of pizza (height multiplied by half the base). So four pizza slices would come to 120 square inches of pizza. If you multiply 120 square inches of pizza with the total number of pizza eaters—33 million—you get your final guesstimate, which is 3,960 million or 3.96 billion square inches of pizza. You can round off your guesstimate to arrive at the final answer of 4 billion square inches of pizza.

There are several other examples you can think of, but try to solve them in a similar manner to come up with viable solutions.

Guesstimates At Your Fingertips

Mastering guesstimates is all about combining training with on-the-spot awareness. This exercise becomes easier if you understand the process that goes into making guesstimates. Harappa’s Ace The Interview course is designed to provide useful tips and tricks as it prepares you for all kinds of guesstimate interview questions through rigorous modules and a world-class faculty. Join professionals from organizations like Mckinsey & Company, Flipkart, Uber, etc. in signing up for the Ace The Interview course and you will never have to sweat over guesstimate questions and answers again.

Explore Harappa Diaries to learn more about answering interview questions such as – ‘Why Are You Interested In This Job?’, How To Answer – Brain Teaser Questions,  Team Leader Interview Questions & Semi-Structured Interview Questions that will help you ace your next interview.

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