The short answer

There isn't one number that suits everyone. It depends on how senior the role is, how many interviews you've done before, how easily you talk when you're nervous, and most of all on what kind of practice you do.

Three goes at answering out loud will usually do more for you than ten read-throughs of your notes, even though reading them feels more reassuring at the time.

Two kinds of preparation

Passive preparation means reading, taking notes and going over answers in your head. It helps you work out what to say, but it doesn't practise saying it. Active preparation means answering out loud, ideally with someone listening who tells you how it went. That's much closer to what you'll be doing in the interview.

What counts as practice

Before getting to how many times, it helps to be clear about what counts. Everything on this list is worth doing, but only the last three are practice.

  • Reading your CV: worth doing so you remember what's on it, but it isn't practice.
  • Writing out STAR answers: helps you work out what each story is and what order to tell it in.
  • Thinking through an answer in your head: helps you decide what you want to say.
  • Saying an answer out loud, alone: this is practice, and it's the easiest kind to fit into a day.
  • Saying an answer out loud in front of someone (or a camera): closer to the real thing. Being watched tends to make you a bit nervous, which is how you'll feel in the interview.
  • Doing that with feedback, then trying again: the most useful practice of all, because you find out what isn't working while there's still time to fix it.

The first three are comfortable, so it's easy to let them take up most of your preparation. The interview itself is much more like the last three: you speak, someone watches, and you can't check your notes. If you've only done the first three, the interview becomes your first real practice run.

Rough numbers for different interviews

These are starting points rather than rules. Do more if you're nervous or haven't interviewed for a while, and less if you interview often.

Minimum
First-round screening call
Even for a short first call, say your answers to "tell me about yourself" and "why this role?" out loud at least twice beforehand. They're likely to come up early, and a couple of run-throughs is usually enough to get your opening out smoothly.
Good
A standard interview for a graduate or junior role
Prepare six to eight STAR stories and tell each one out loud at least three times, on different days rather than all at once, because that helps them stick. Do at least one full practice interview of 30–40 minutes with questions you haven't seen, in front of another person or a camera if you can. That's roughly 2–3 hours of speaking practice over 3–5 days.
Strong
Competitive roles: Big Four, consulting, large graduate programs
Do everything above, with more rounds of practice and feedback. Your stories should come out easily without sounding memorised. The aim is to take a question you've never heard and still find your way to one of your stories. For that, plan on five to seven full spoken sessions and at least two practice interviews where someone gives you feedback, which comes to about 4–6 hours of speaking practice over a week.

How to tell you're ready

Counting sessions only tells you so much. You're probably ready when:

  • You can answer "tell me about yourself" in under 90 seconds without stopping to think
  • You can give a clear STAR answer to a question you didn't prepare for
  • Your answers sound like you're talking to someone rather than reciting
  • A question has stumped you in practice and you've recovered from it
  • Your last two practice interviews felt easier than your first two

If all five are true, you've probably done enough. If none of them are yet, keep going, however many hours you've already spent with your notes.

3×
Each main story, out loud
A sensible minimum, ideally on different days
2
Full mock interviews
At least one with questions you haven't prepared for, and one where you get feedback
1×
Cold run the day before
Answer three or four likely questions without looking at your notes first, as you'll have to on the day

Spread it out instead of cramming

Practising for an hour on each of three days will usually get you further than three hours the night before. You remember things better when you come back to them over several days than when you do it all in one go.

So start at least five days before the interview if you can. You don't need to do more in total, just spread it out.

A long session the night before also cuts into your sleep and can leave you more wound up, and neither helps on the day.

The night before

The night before is when the interview feels most real, so it's tempting to make it your biggest night of preparation. Keep it to a short run through your main stories and get to bed at a reasonable hour.

Practise with feedback on every answer

InterviewZap writes behavioural interview questions from your CV and the job description, so you're answering ones you haven't seen before. Answer out loud or by typing, and after each answer you'll see what was missing and a stronger way to put it.

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Can you over-prepare?

Yes, in one way. If you rehearse an answer until you've memorised the wording, it starts to sound recited. Recited answers tend to come out flat and a bit too smooth, and they lose the small details that make a story believable.

Aim to know each story well and leave the exact words to the moment. You shouldn't have to think about what happens next in the story, but you should still be choosing how to say it as you go.

If your answers start to sound robotic, take a day off and come back to them fresh. An answer you haven't said for a day usually sounds more natural than one you've just said fifteen times in a row.

Quick summary

Go by the five checks above rather than a number of sessions. To get there, answer out loud over several days, ideally with someone listening who gives you feedback.

If you're short on time, spend it on speaking practice rather than more reading.

The one-week plan

Days 1–2: Read the job description closely and write out your STAR stories. Day 3: Your first spoken session. Answer five questions out loud and record yourself. Day 4: Listen back, note what to fix, then do a second spoken session. Day 5: A full 30-minute practice interview with questions you haven't seen. Day 6: A light run through your main stories, then an early night. Day 7 (interview day): Ten minutes going over your opening answer, and nothing new.