The short answer
| Company type | What works | What to avoid |
|---|---|---|
| Big tech | Smart casual - a clean shirt or plain top | A full suit; it reads as unfamiliar with the field |
| Startup | Casual but deliberate - a decent t-shirt or shirt | Anything that looks like a bank interview |
| Finance or defence tech | Business casual, or a suit if they say so | Being the most casual person in the room |
| Consultancy or agency | Business casual | Overthinking it |
| Any video interview | A solid-coloured top, no busy patterns | Stripes and small checks, which shimmer on camera |
Software engineering is genuinely informal
In most engineering organisations your interviewers will be in t-shirts. A three-piece suit at a startup does not read as respectful, it reads as not knowing the industry - which is a small, unfair signal, but it is a real one for a candidate whose industry familiarity is already in question. Clean, neat and unremarkable is the target. The ideal outcome is that nobody remembers what you wore.
Video interviews, where it actually changes
Most new grad and internship rounds are remote now, and the camera has its own rules that have little to do with formality:
- Solid colours. Fine stripes and small checks produce a moiré shimmer that is distracting on compressed video.
- Mid-tones beat extremes. Pure white blows out under auto-exposure and pure black loses all detail.
- Do not match your background. You will blend into the wall, especially if any background blur is on.
- Check it on camera first. Thirty seconds in the actual meeting software tells you more than any guidance.
- Light in front of you, not behind. A window at your back turns you into a silhouette, which is far more noticeable than clothing.
The rest of the remote setup matters more than the outfit and is covered in live coding interview tips for Zoom and Teams and, for recorded rounds, HireVue software engineer questions.
If you genuinely cannot tell
- Ask the recruiter. It is a completely normal question and they answer it constantly. Nobody has ever been marked down for asking.
- Look at the company's own photographs on their careers or team page.
- Default to one step smarter than you think, which for most software roles means a plain shirt or a neat sweater.
What to spend the worry on instead
The things that actually move a technical interview are whether you talk through your reasoning, whether you ask clarifying questions, and whether you can recover when you are stuck. If you have an evening before an interview, spend it saying a problem out loud rather than deciding on a shirt - the method is in how to use AI for interview prep, and if nerves are the real issue, interview anxiety techniques is more to the point.
Where CoPilot Interview fits
Disclosure: we build an interview assistant, so treat this as a disclosed pitch. CoPilot Interview is a native Windows and macOS app that puts suggested answers on your own screen in about four seconds during live rounds, with a permanent free tier that needs no credit card - which is a better use of your pre-interview evening than your wardrobe.
Frequently asked questions
What should I wear to a software engineer interview?
Smart casual at most companies - a clean shirt or a plain top. A full suit is usually wrong for big tech and startups, where it reads as unfamiliarity with the industry. Finance, defence tech and consultancies lean more formal, so check if you are unsure.
Should I wear a suit to a tech interview?
Usually not. Most engineering interviewers will be in t-shirts, and a suit at a startup reads as not knowing the field rather than as respectful. The exceptions are finance, defence tech and some consultancies, where business formal is normal.
What should I wear for a video interview?
A solid mid-tone colour. Fine stripes and small checks shimmer on compressed video, pure white blows out under auto-exposure and pure black loses detail. Avoid matching your background, and check yourself on camera in the actual meeting software first.
Is it okay to ask the recruiter what to wear?
Yes, and they are asked constantly. It is a completely normal question and nobody has been marked down for asking it. Looking at photographs on the company's careers or team page is another quick way to calibrate.
Walk into the round with a second pair of eyes
CoPilot Interview is a native Windows and macOS app that puts suggested answers on your own screen in about four seconds, across coding, system design and behavioral rounds. The free tier is permanent: 15 minutes a day, no credit card.
Try it free