McKinsey Solve: The Complete 2026 Guide

What is McKinsey Solve?

McKinsey Solve, also known as the McKinsey Problem Solving Game, the Imbellus game, or the McKinsey digital assessment, is the gamified test McKinsey sends to most candidates after resume screening and before first-round interviews. It replaced the written Problem Solving Test (PST) starting in 2020 and has evolved continuously since: the original Ecosystem Building and Plant Defense games have been phased out, and the 2026 assessment is built on the Redrock Study, Sea Wolf, and, on a growing share of invitations, the Sustainable Futures Lab.

That evolution matters for your preparation, because much of the advice online still describes retired games. If a resource teaches you to build food chains or place defensive towers, it is describing a test you will not take. The current modules are a timed data analysis exercise, a constrained optimization game, and a behavioral judgment scenario.

Solve is deliberately designed so that business knowledge does not help. The games run in research and ecology settings precisely so that candidates from any degree background face the same problem cold. What it measures is cognition: how you process data, make decisions under time pressure, and allocate attention.

The two versions: 65 vs 85 minutes

As of 2026, McKinsey runs two Solve configurations and assigns them by region and role. You cannot choose, and the reliable signal is the total duration stated in your invitation email.

The practical takeaway: read your invitation carefully the day it arrives. The duration tells you whether the Sustainable Futures Lab is on your menu, and that decides whether your preparation has two workstreams or three.

The three Solve games

Redrock Study (35 minutes). The data and math module. You play a researcher given an objective, a page of study material, and a Research Journal to collect data into. Part 1 runs through Investigation, Analysis, and Report phases; Part 2 is six independent mini cases. Roughly 60 to 70 percent of the questions are quantitative, and Redrock carries the largest share of the assessment.

Sea Wolf (30 minutes). The optimization module, also called the microbe or ocean cleanup game. For each of three polluted sites you select three microbes whose averaged attributes must land inside the site's required ranges without carrying undesired traits. Each site is scored as an efficiency starting at 100 percent with deductions per miss.

Sustainable Futures Lab (20 minutes, 85-minute invites only). The behavioral module added in early 2026. You join an environmental research team and work through a connected scenario: one priority ranking plus twelve decisions, scored across five judgment traits including prioritization, trade-off balancing, and stakeholder effectiveness.

Dual scoring: product and process

Every Solve module feeds two scores, and understanding both changes how you should prepare.

The product score is your results: correct Redrock answers, Sea Wolf site efficiencies, defensible SFL decisions.

The process score is recorded from telemetry while you play: what data you collect and what you ignore, how you navigate, how you sequence decisions, and how you spend time. Two candidates with identical answers can score differently because one worked deliberately and the other thrashed.

Scoring is percentile-based against your candidate pool rather than a fixed pass mark, with the common estimate that you need to land around the top quartile to advance. There is no partial-test shortcut: a strong Redrock cannot fully rescue an abandoned Sea Wolf, because each module feeds the profile.

Pass rates and what Solve filters for

McKinsey publishes no official pass rate, but converging estimates from candidate communities and prep providers put it around 20 to 30 percent, against a pool measured in the hundreds of thousands of test takers per year. Solve is a genuine filter: for most applicants it eliminates more candidates than any interview round.

What it filters for is consistent across the modules: fast and accurate processing of unfamiliar information, sensible time allocation, decision-making that stays structured under pressure, and in the SFL, judgment that holds together across a scenario. None of these reward cramming; all of them reward realistic practice.

The attempt policy raises the stakes further. Solve is one attempt per application cycle, and an unsuccessful McKinsey application typically means waiting in the range of one to two years before reapplying. Treat the sitting like a final-round interview, because in expected value terms it is one.

How to prepare for McKinsey Solve

1. Confirm your version, then split your prep

Read the duration in your invitation. A 65-minute invite means two workstreams: Redrock's data-and-math cycle and Sea Wolf's constraint optimization. An 85-minute invite adds SFL's judgment format as a third, smaller stream.

2. Rebuild consulting math speed

Percentages, ratios, weighted averages, and growth rates cover nearly all of Redrock's quant and the arithmetic behind Sea Wolf's averaging. Short daily drills beat long weekend sessions; our free math drills target exactly this mix.

3. Practice inside the real formats

The dual scoring system is the reason generic puzzle practice underperforms: the process score rewards candidates who already know the interfaces. Run each game at least once untimed to learn the mechanics and once timed to learn the pace, and read each game's deep guide first: Redrock, Sea Wolf, and the Futures Lab.

4. Rehearse pacing, not just questions

Almost every failure story is a pacing story: over-collecting in Redrock's Investigation, perfecting Sea Wolf's first site, reading SFL too slowly. After each timed practice run, audit where the minutes went before reviewing what you answered.

Test-day logistics

Environment. A quiet room, a reliable computer and internet connection, and a full battery or power cable. Solve runs in the browser and a dropped connection mid-game is a problem you do not want to debug under the clock.

Use the tutorials. Each game's tutorial is untimed. Take it slowly even if you have practiced; it is free acclimatization and the clock only starts with the game itself.

Timing within the window. Invitations give a completion window of several days. Take the test when you are rested and sharp rather than the night it arrives or the night it expires; sustained attention is the resource every module spends.

Have paper ready. A pen and paper for jotting intermediate numbers is generally permitted and useful, especially in Sea Wolf. Calculators outside the in-game one are not part of the intended experience; rely on the tools the games provide.

McKinsey Solve: frequently asked questions