Microsoft Online Assessment 2026: Format, Topics & Prep Guide

Microsoft's internship recruiting runs on a well-oiled pipeline: apply, receive an online coding assessment, and — if you clear it — move on to interviews. The OA is the gate most candidates underestimate, largely because Microsoft does not publish much about it. This guide summarizes what is widely reported about the format and how to prepare for it.

What is the Microsoft OA and what format should you expect?

After your application passes the resume screen, Microsoft sends an online assessment link, typically with a several-day completion window. Based on aggregated candidate reports, the SWE intern assessment looks like this:

• Platform: a Codility-style environment — in-browser editor, custom test cases, and automated scoring against hidden tests.
• Questions: typically two to four coding problems in 60–90 minutes, mixing easy warm-ups with genuine mediums. Reports vary by team and season, so expect anywhere in that range rather than a fixed count.
• Languages: the usual set — C++, Java, Python, JavaScript, and more.
• Scoring: automated, with partial credit. Both correctness and edge-case handling matter; a solution that passes the visible tests but fails hidden edge cases loses significant points.

Microsoft generally does not include a heavy behavioral or workstyle section in the OA itself — culture evaluation happens later, in the interview rounds. The OA is almost purely about code.

What topics should you expect?

Microsoft's OA pool, like its interview question pool, favors solid fundamentals over exotic tricks:

• Arrays and strings: two pointers, sliding window, merging and interval problems.
• Hash maps: frequency counting, pair finding, deduplication.
• Linked lists: reversal, midpoint, cycle detection — Microsoft has a long history of asking these.
• Trees: traversals, balanced-tree checks, lowest common ancestor.
• Dynamic programming (light): classic one-dimensional DP — climbing stairs, house robber, coin change — rather than knapsack variants.
• Math and bit manipulation: simple counting, parity, and XOR problems appear more often at Microsoft than at most peers.

Microsoft interviewers famously like problems with a clean "aha" — a short, elegant solution once you see the trick. The OA rewards exactly the same instinct.

A 2-week study plan

Week 1 — breadth across the Microsoft pool.

• Days 1–2: arrays and hash maps — the Two Sum pattern and its variants until the hash-map instinct is automatic.
• Days 3–4: linked lists and trees. Reversal, cycle detection, traversals, LCA — write them from scratch, twice.
• Day 5: light DP — the three classics (climbing stairs, house robber, coin change), then one 2-D problem if time allows.
• Weekend: two timed mock OAs — three mediums in 75 minutes each — with strict no-lookup rules.

Week 2 — accuracy and edge cases.

• Days 1–2: redo every miss from week 1, then practice "hidden test case thinking": for each problem, list three edge cases (empty, single element, duplicates) before coding.
• Day 3: bit manipulation and math basics — XOR pairs, counting problems, parity checks.
• Day 4: one final full-length mock under exact conditions, followed by a careful review of what cost you time.
• Day before the OA: review your pattern notes and rest. A clear head beats one more problem.

For a structured longer plan, see the 4-week interview prep plan.

How Easy Code Interview helps you practice

Microsoft's Codility-style environment rewards speed and correctness — the two things that erode each other under time pressure. Easy Code Interview lets you rehearse that exact tradeoff: work a timed problem on screen, then get the short answer and a detailed explanation on your second device to verify your approach and understand the pattern while it's fresh. Use it to drill the Microsoft classics until the "aha" moment arrives in seconds, not minutes.

Verdict

The Microsoft OA is beatable with two weeks of disciplined, fundamentals-first preparation because its question pool is one of the most predictable in the industry. Clear the OA, and you reach Microsoft's interviews — where a warm, teamwork-oriented culture fit matters as much as algorithmic polish. Prepare the code for the OA, and prepare your collaboration stories for what comes after.

Frequently Asked Questions

How many questions are on the Microsoft OA?

Reports vary — most candidates describe two to four coding problems in 60–90 minutes, depending on team and season. Prepare for the upper end: three mediums in 75 minutes is a good mock format.

Does Microsoft use Codility for its OA?

The environment is widely described as Codility-like — an in-browser editor with sample and hidden test cases — whether or not it is Codility under the hood. Practice in any similar judge to get comfortable with the format.

Is partial credit given?

Yes — solutions are scored by how many test cases pass, so a correct-but-slow approach still earns points. Under time pressure, a working brute force is better than an unfinished optimal one; then optimize if time remains.

What language should I use for the Microsoft OA?

Whichever you are fastest and most accurate in. Python is the most common choice for its concision; C++ and Java are fine if that's where your muscle memory lives.

What comes after the OA?

Typically one or two 45–60 minute interviews (coding plus behavioral), often with an "as appropriate" interviewer added on the same day for strong candidates. Microsoft's behavioral bar leans on collaboration and growth mindset — prepare a few STAR stories alongside your coding prep.