For most one-to-one product interviews, book 30 minutes. Use 15 minutes when you have one narrow question about a recent event. Use 45 to 60 minutes when you need to understand a complex workflow, reconstruct several events, or combine an interview with another activity.
Those are planning ranges, not scientific thresholds. There is no universally correct user interview length. The right duration depends on what you need to learn, how much context the participant must recall, the method you are using, and the participant’s needs.
The UK Government Service Manual gives a broad range of 30 minutes to 2 hours for in-depth interviews. It also notes the trade-off: longer sessions can produce more detail, but they are harder to recruit for. For a technical founder running focused product research, 30 minutes is usually the most useful place to start.
User interview length at a glance
| Length | Best for | Usually too short or long for |
|---|---|---|
| 15 minutes | One recent event, a narrow churn debrief, or one decision you want reconstructed | Open-ended discovery across several topics |
| 30 minutes | A focused story-based interview, feature feedback, or one buying, onboarding, or workflow story | A complex end-to-end journey with several people, tools, or tasks |
| 45–60 minutes | Broad problem discovery, detailed workflow mapping, sensitive or complex context, or an interview plus a short activity | A single question that can be answered from one concrete example |
Treat the table as a starting point. Pilot the guide once, watch where you rush or repeat yourself, and change the slot before recruiting the full round.
When a 15-minute user interview works
A 15-minute interview works when the research question is small enough to fit.
Good 15-minute objectives sound like this:
- What happened the last time a customer abandoned the export?
- What triggered this account to cancel?
- How did this user decide between two plans?
- What confused this participant during one step of onboarding?
Each question points to one event. The participant does not need to explain their entire role, workflow, history with the product, and list of unmet needs before you can learn something useful.
The key is to ask for a specific past example. Teresa Torres recommends grounding interviews in specific instances of past behaviour because general questions invite summaries and speculation. “Walk me through the last time the export failed” gives a short interview a chance to work. “What do you think of our reporting?” can fill 15 minutes without producing much evidence.
A simple 15-minute plan:
- Opening and consent — 2 minutes. Explain the purpose, recording, privacy, and time available.
- One concrete story — 9 minutes. Reconstruct what happened, what the person did next, and why.
- Meaning and close — 4 minutes. Clarify the consequence, ask what you missed, and thank them.
Do not squeeze five research questions into the slot. If you need five topics, book more time or split them across separate conversations.
A brief churn interview is a good example. Someone who has cancelled is already doing you a favour by responding. Ask about the trigger, the build-up, the alternative they chose, and what might have changed the outcome. Do not turn the call into a retention attempt.
Why 30 minutes is the best default
Thirty minutes gives a focused interview room to settle, collect a real story, and follow an unexpected thread without demanding an hour from a busy participant.
It also matches established product-discovery practice. Product Talk’s story-based examples run over 20 to 30 minutes. The purpose is not to cover a long questionnaire. It is to help the participant reconstruct a specific experience while the interviewer listens for context, goals, decisions, workarounds, and unmet needs.
The first answer is rarely the whole answer. Nielsen Norman Group advises interviewers to start with easy questions, build rapport, and probe with neutral follow-ups. A 30-minute slot leaves time for that progression. A 15-minute slot may force you to choose between a humane opening and useful follow-up questions.
Here is a practical 30-minute plan:
- Opening and consent — 3 minutes.
- Context and warm-up — 4 minutes.
- Core story — 15 minutes.
- Follow-up on the most important thread — 5 minutes.
- Final thoughts and close — 3 minutes.
The times are a budget, not a script. If the participant reaches the important story immediately, follow it. If the objective is covered after 22 minutes, finish early. Respecting someone’s time is more valuable than filling the calendar.
When to book 45 or 60 minutes
Book a longer interview when the objective contains several connected parts that cannot be understood responsibly in a short call.
Examples include:
- mapping an end-to-end workflow across several tools and hand-offs;
- reconstructing a long B2B buying decision with multiple stakeholders;
- understanding an unfamiliar domain before deciding what to build;
- discussing a complex or sensitive experience at the participant’s pace;
- combining an interview with a prototype walkthrough or usability task.
The phrase “problem discovery” does not automatically justify an hour. A narrow discovery question may fit in 30 minutes. A broad “show me how month-end reporting works from start to finish” study may need 60.
Longer sessions need stronger preparation. Reduce the guide to essential topics, decide which follow-ups are optional, and include a clear stopping condition. For sensitive research, remind the participant that they can skip a question, pause, or stop. For people with access needs, ask about their preferred communication method and a reasonable session length before the interview. The Government Digital Service recommends tailoring remote sessions to the participant rather than assuming one duration works for everyone.
If the conversation is still productive at the scheduled end, ask before continuing: “We have reached the time we agreed. I have one more question. Would you like to continue for five minutes, or should we stop here?” Never quietly take extra time.
Do not borrow usability-test timings as interview rules
User interviews and usability tests answer different questions.
An interview helps you understand experiences, perceptions, decisions, and remembered behaviour. A usability test asks someone to perform tasks with a design while you observe what happens. You can combine the methods, but the session then needs time for both.
Nielsen Norman Group says a typical usability test runs 60 to 90 minutes and that participants tire after that range. That is guidance about usability sessions, not evidence that every user interview should last 60 minutes or stop at 90.
Its interview guide makes the distinction clearer: a combined interview and usability test might run 90 minutes rather than 60. If you use both methods, write separate objectives and budgets for the interview and the tasks. Do not spend 45 minutes asking for opinions and leave 15 minutes to observe the behaviour you came to test.
Choose the length from the research objective
Before opening your calendar, write one sentence:
By the end of this interview, I need to understand…
Then use this decision guide:
One recent event or decision
Start with 15 minutes.
Examples: a cancellation trigger, a failed task, a support escalation, or a recent plan choice.
One complete story with context and follow-ups
Start with 30 minutes.
Examples: an onboarding experience, the last time someone used a workaround, or how a buyer chose a product.
A broad workflow or several connected stories
Start with 45 to 60 minutes.
Examples: a team process with hand-offs, a long purchase journey, or open problem discovery.
An interview plus prototype tasks
Budget the activities separately. A short interview and a short task do not automatically make a short session. Pilot the full sequence, including setup and consent.
A participant who may need a different pace
Ask them. Accessibility, language, fatigue, subject sensitivity, and communication method can all change the right duration.
Protect the time you booked
An interview can be an hour long and still feel rushed if the guide is unfocused. It can be 20 minutes long and produce a useful story if the objective is clear.
Use these rules to protect the slot:
- Keep the research objective visible. It tells you which tangents to follow and which to leave alone.
- Ask about events, not predictions. Nielsen Norman Group recommends critical incidents and specific cases because “usual” behaviour often becomes an idealised account.
- Put essential questions first. If the call ends early, you still answer the decision-driving question.
- Use a guide, not a questionnaire. Follow the participant’s story instead of racing through every prompt.
- Pilot with a realistic participant. A colleague who knows the product may move much faster than a real user.
- Leave a buffer between calls. Use it to write a short interview snapshot, reset, and adjust the next guide.
- End when the objective is covered. More words are not automatically more evidence.
Interview length and sample size are different decisions
A longer interview does not compensate for talking to the wrong people or too few kinds of people.
Session length follows the depth and complexity of the objective. Sample size follows the breadth of the study and the diversity of the population. Nielsen Norman Group’s review of interview sample sizes explains that broader research goals and more varied populations generally require more interviews to reach saturation.
If your audience includes administrators, end users, and buyers, one 60-minute conversation with an administrator cannot represent all three. You may learn more by running focused 30-minute interviews with each role. See the separate guide to how many users you should interview for a practical sampling plan.
Cadence matters too. Product Talk recommends interviewing customers at least weekly to create a persistent feedback loop. A sustainable 30-minute conversation every week is usually more useful than an exhausting research sprint followed by three months of silence.
How interview length works in Maren
Async text interviews do not map neatly to calendar slots. Participants read, think, and reply at their own pace, so a “30-minute interview” is less useful than a clear estimate and the right amount of depth.
In Maren, you choose the research goal, interview style, and depth. Maren then adapts her follow-up questions to what each participant says. A churn conversation stays brief and respectful. Problem discovery allows more room for stories and workarounds. The participant’s pace still affects the actual completion time.
This is also why async and live user interviews should not use identical guides without adjustment. A live moderator can see hesitation and negotiate extra time. An async interviewer must communicate scope clearly, avoid repetitive questions, and let the participant stop without pressure.
The principle is the same in either format: choose enough depth to answer the research objective, then stop.
Frequently asked questions
Is 15 minutes too short for a user interview?
Not if you have one narrow question tied to a recent event. It is usually too short for open discovery across several topics.
Should all user interviews be 30 minutes?
No. Thirty minutes is a useful default for a focused one-to-one product interview, not a rule. Pilot the guide and adjust for the method, objective, and participant.
Is a 60-minute user interview too long?
Not for a complex workflow, broad discovery study, or combined interview and activity. It is too long when the research question can be answered in one short story. End early when you have what you need.
Can an interview run past the booked time?
Only with the participant’s explicit agreement. A better plan is to identify optional questions in advance and stop on time if the participant cannot continue.
The simple answer
If you are unsure how long a user interview should be, book 30 minutes and pilot the guide.
Move down to 15 minutes when you need one recent story. Move up to 45 or 60 when the objective genuinely requires more context or another activity. Tell the participant how long it will take, keep the promise, and finish early when the conversation has answered the question.
The quality of an interview does not come from the number on the calendar. It comes from a clear objective, the right participant, concrete questions, careful follow-ups, and the judgement to know when you have learned enough.