This article was first published on Business Insider

If you’re interviewing for a job at a startup, you might be offered stock options. Sometimes, startups offer stock options instead of a higher salary.

It’s not always easy to tell the true value of what you’re being offered. And sometimes, what can sound like a lot of stock in a company can actually amount to very little.

“First, you should realize that when you’re joining a startup, the likely outcome is nothing,” Scott Belsky, a startup investor and entrepreneur, tells Business Insider. “But if you are sacrificing salary, you have a right to upside. And you also have a right to understand what your upside might be.”

Belsky put early money into startups like Uber, Pinterest and Warby Parker. He also founded a company, Behance, that raised a few million dollars and was later acquired for about $150 million.

He says there’s one question everyone should ask, that will give them insight into what stock option grants might be worth, before they accept a startup job.

“What you can do, when it’s in the final stage of accepting an offer, is you can ask a simple question,” he says.

“Based on the equity you’re offering me, what would my stake be work if the company were acquired for $200 million; for $500 million; for $1 billion?”

The answer might surprise you, and it depends on a number of factors, including how much money the startup has raised, and on what terms the money was raised on.

Belsky recalled a recent conversation with an entrepreneur who was exploring an acquisition offer from a “unicorn” startup — a private company with a valuation of $1 billion or more.

The founder was excited about it, until Belsky encouraged him to ask the simple question. The answer he got was so disappointing, it killed the deal.

“He said it was like an $85 million acquisition offer for a company that had raised basically seed funding,” Belsky recalled in an interview for Business Insider’s podcast, “Success! How I Did It.”

“And he was really psyched about it. And he had not even asked these questions yet. I said to him, ‘If you got your company acquired right now for $85 million in equity from this unicorn company, and you found out that they ended up exiting at the valuation they raised their last financing at, ask them like how much you would end up getting.’ He ended up learning that it was basically nothing. And he didn’t go through with it.”

Check out the episode below for Belsky’s career advice, and his advice for anyone looking to join a startup.

Here’s a transcript from the portion of the interview where he offers advice for prospective startup employees:

Shontell: So, talk a little bit about what employees can do to realize what kind of a situation they’re in when they join a startup. What questions should they be asking? What do they need to know about stock options? How do you know if — you know it sounds great when your company raises $50 million to $100-plus million, but what does that actually do to you?

Belsky: Sure. The two things that I think are important are one, is to realize that when you’re joining a startup the likely outcome is nothing. And even if the company does OK and has an exit, if you’re a later-stage employee, you should really be making sure that you get an experiential education that is extremely rewarding, first and foremost. But if you are sacrificing salary, you have a right to upside. And you also have a right to understand what your upside might be.

And so rather than suggest to every engineer or designer or anyone else out there to get copies of term sheets and look — I mean it’s really hard to do all that stuff and to ask a million questions. You’re probably not going to get far in the interview process if those are your questions. But what you can do, when it’s in the final stage of accepting an offer, is you can ask a simple question. Based on the equity you’re offering me, what would my stake be work if the company were acquired for $200 million, for $500 million, for $1 billion? Just ask that question.

Your answer might be that if it’s acquired for $200 million, your stake is worth zero. If it’s acquired for $500 million, your stake is worth zero. And if it’s acquired for $1 billion, your stake is worth $100,000. Or whatever. But at least that answer can give you some sense of really what’s going on. And I think that’s the company’s obligation to at least give you some directional guidance on what the likely value of your equity would be in those circumstances, and those are the questions people should ask.

Shontell: And any negotiating tips if you do hear that what you’re being offered is zero?

Belsky: Well I think that just having that knowledge allows you to say something like, “Well, if the company were to be acquired for $1 billion and my equity is worth zero, maybe my salary should be a little higher,” right? So it’s that kind of calculus. Recently an entrepreneur called me with an acquisition offer from one of these unicorn companies. And he said it was like an $85 million acquisition offer for a company that had raised basically seed funding. And he was really psyched about it.

And he had not even asked these questions yet. And when he did, because I said to him, if you got your company acquired right now for $85 million in equity from this unicorn company, and you found out that they ended up exiting at the valuation they raised their last financing at, ask them like how much you would end up getting. And he ended up learning that it was basically nothing. And he didn’t go through with it. So, I think he could’ve negotiated a much larger acquisition price I think based on that. But he chose not to just proceed at all. I think these are the types of questions and they open up obviously the types of negotiating points you could pursue.

Shontell: Are companies obligated to tell you?

Belsky: I don’t think they’re obligated to. But then as a prospective employee, you can decide whether you want to work for them or not. And that’s just part of the calculus.