Can You Use a Calculator in the McKinsey Problem Solving Test? A Definitive Guide

Can You Use a Calculator in the McKinsey Problem Solving Test?

An interactive tool and guide to understand the rules for the PST and Solve Game.

Assessment Calculator Policy Checker

Which test are you taking?

Select the specific assessment you are preparing for.

What is the test format?

The format significantly impacts tool usage rules.

Have you received explicit instructions FORBIDDING a calculator?

Always defer to official communication from the firm.

What is the ‘can u use calculator in online problem soving test mckinsey’ Question?

The question of whether you can use a calculator in the McKinsey online problem-solving test is one of the most common and critical points of confusion for candidates. For decades, the answer for the traditional paper-based McKinsey Problem Solving Test (PST) was a definitive “No”. This rule forced candidates to rely heavily on mental math, estimation, and logical reasoning—skills McKinsey values highly.

However, with McKinsey’s transition to digital assessments like the McKinsey Solve Game (also known as the Imbellus game), the rules have become more nuanced. Some modules within the Solve game include a built-in calculator, and using it is tracked as part of the assessment. This shift means candidates must not only solve the problem but also demonstrate good judgment on *how* they use the tools provided. Answering this question incorrectly can mean either failing to prepare correctly or being disqualified for not following the rules.

How to Determine the Calculator Policy

There isn’t a mathematical formula, but a logical one. Our calculator uses this decision-making tree to provide its recommendation. The policy is determined by a few key variables.

Variables Influencing Calculator Use
Variable	Meaning	Unit (or Type)	Typical Range
Official Instructions	Direct communication from the recruiting team.	Boolean (Yes/No)	This is the most important factor and overrides all others.
Test Type	The specific assessment being administered.	Categorical	PST, Solve Game, BCG Potential Test, etc.
Test Format	How the test is delivered and monitored.	Categorical	In-Person, Online Proctored, Online Unproctored.
Built-in Tools	Whether the testing software provides an on-screen calculator.	Boolean (Yes/No)	The presence of a tool implies it is permitted, and likely tracked.

For more details on test preparation, see our guide on McKinsey PST Practice.

Practical Examples

Example 1: The Classic McKinsey PST

Input (Test): McKinsey Problem Solving Test (PST)
Input (Format): In-Person Paper-Based
Input (Instructions): No explicit instructions received, but historical precedent is known.
Result: No. Calculators are not permitted. All calculations must be done mentally or on provided scratch paper.

Example 2: The Modern McKinsey Solve Game

Input (Test): McKinsey Solve Game (Imbellus)
Input (Format): Online Unproctored
Input (Instructions): Instructions mention an online platform with various tools.
Result: Yes, if a built-in calculator is provided. The Solve game often includes an in-game calculator. You are expected to use the provided tool, and your usage might be part of the evaluation. Using an external calculator is risky and may be against the rules.

How to Use This ‘Can You Use Calculator’ Calculator

This tool helps you quickly assess the likely policy for your specific situation. Follow these steps for an accurate analysis:

Select the Test: Choose the exact test you’ve been invited to take from the first dropdown. The rules for the BCG Potential Test can differ from McKinsey’s.
Specify the Format: Indicate whether your test is online, in-person, proctored, or unproctored. This is a crucial factor.
Confirm Instructions: Check the box if you have received an email or document that explicitly forbids calculators. This is the most critical input.
Analyze the Result: The calculator will provide a clear “Yes,” “No,” “Unlikely,” or “Check Official Instructions” verdict, along with the reasoning based on your inputs.

Chart: Importance of Mental Math Skills for the PST

This chart illustrates the relative importance of key quantitative skills when a calculator is not permitted. Mastery of Consulting Math is essential.

Key Factors That Affect Calculator Policy

Several elements influence a firm’s decision on calculator usage. Understanding them helps you anticipate the rules.

The Firm’s Philosophy: McKinsey has historically emphasized on-the-spot quantitative thinking, hence the traditional no-calculator rule.
Test Security and Fairness: In unproctored online tests, providing a built-in calculator ensures all candidates have access to the same tools.
Skill Assessment Goal: If the goal is to test pure quantitative reasoning, calculators are excluded. If it’s about data analysis within a digital environment, a calculator might be included as part of that environment.
Evolution of Recruiting: As recruiting moves online, firms adapt their assessments. The McKinsey Solve game is a prime example of this evolution.
Logistical Simplicity: A blanket “no calculator” rule is easiest to enforce in a paper-based, in-person setting.
Type of Math Required: PST questions are designed to be solvable without a calculator, often through estimation or simplification. Explore different Case Interview Prep to practice these skills.

Frequently Asked Questions (FAQ)

1. What happens if I use a calculator when it’s not allowed?

You risk immediate disqualification. For proctored online tests, this can be detected. For in-person tests, it’s considered cheating.

2. If a built-in calculator is provided in the Solve Game, must I use it?

It is highly recommended. The platform tracks user actions, and your “process score” may include how you interact with the available tools. Avoiding it might be seen as inefficient.

3. Is mental math still important if a calculator is available?

Yes. Mental math is crucial for quickly estimating answers and cross-checking the calculator’s output. Over-reliance on the tool can slow you down, which is a major handicap in a timed test.

4. Does the policy apply to other consulting firms like BCG or Bain?

Not necessarily. Each firm has its own assessment and policies. The BCG Potential Test and Bain Online Assessment have their own specific rules.

5. What kind of math is on the McKinsey PST?

It focuses on business math: percentages, ratios, profit calculations, break-even analysis, and data interpretation from charts and tables. The calculations are usually straightforward but need to be done quickly and accurately.

6. Why did McKinsey forbid calculators for so long?

To directly test a candidate’s ability to reason quantitatively and perform quick, back-of-the-envelope calculations under pressure—a core skill for a consultant.

7. Can I use scratch paper?

For the paper-based PST, yes, you can write in the test booklet. For online tests, check the specific instructions; sometimes a physical whiteboard or scratchpad is permitted.

8. Where can I find official practice tests?

McKinsey’s official career website provides practice materials for both the PST and provides information on the Solve game. This is the best source for preparation.