What a partner asks in ten minutes about your numbers

YC interviews last ten minutes. Two or three partners are on the call with your application open, there are no slides, and the guide YC publishes for invited founders says it plainly: "We only do two things at interviews: we ask you questions, and we look at what you've built so far."

A first partner meeting at a seed fund is longer, but it works the same way. The deck gets you into the room, and then somebody stops you on slide six and asks about the numbers.

This is what they ask, what it sounded like when founders were not ready, and how to prepare without rehearsing a script.

The questions YC says it asks

YC's interview guide lists the questions partners often ask a company that has launched: "Where do new users come from? What is your growth like? How much are your users using the product, and do they stick around? What are your unit economics?"

Four of those are about numbers, and every seed investor asks some version of them. A fifth comes up in almost every meeting even though it is rarely on a list: what do you burn, and how long does the money last?

The same guide says two things founders tend to miss. You don't need every number memorised: "it is helpful to have your key metrics written down someplace where you can quickly reference them during the interview." And the numbers get checked: "if you state numbers in the interview we may ask for verification of them afterwards."

So the job is not to remember everything. It is to say numbers that are consistent, that you can explain, and that still hold when someone looks at them a week later.

"Where do new users come from?"

This is a question about what a customer costs, even when it sounds like a question about channels.

On The Pitch, the founder of an insulated lunch bag brand pitched five investors for a $2M seed round. One of them stopped on acquisition: "$57 per customer?" She had cut ad spend by 80 percent "in an effort to preserve burn, extend our runway," which kept the company alive and left growth flat. All five passed. One of them said: "I just can't invest in flat businesses."

She knew her numbers. The numbers had a trade-off in them, burn against growth, and the investors worked it out live, in front of her, before she had framed it herself.

A good answer: the channels that bring customers today, what one customer costs in each, and what happens to growth if you spend more or less. If you cut spend to extend runway, say so first, with the number. More on this in CAC and LTV for SaaS founders.

"What is your growth like?"

Growth is easy to state and easy to blur, because it depends on what you call revenue.

In another episode of The Pitch, a founder of an on-campus delivery business was asked whether his $1.2M run rate was gross merchandise value. "Correct," he said, and later in the conversation it became "GMV plus delivery fees." Gross margin started at "roughly 30 to 40% right now per month" and a few minutes later "it takes us closer to 25%." One investor did the arithmetic out loud, "25% of $600k?", and the founder corrected him, "25% of $1.2."

Nothing was hidden. The definitions moved under questioning, and that was enough to make every other number in the pitch feel soft.

A good answer: one definition of revenue, written down before the meeting, and growth stated on that definition, month over month, with the period named. If you have both GMV and net revenue, say both and say which one the growth number uses. The SaaS metrics guide covers the definitions.

"Do they stick around?"

Retention is where a business that looks fine on growth starts to look different.

Brian Nichols at Hustle Fund wrote about a founder with real traction who could not say how much of his revenue came from returning customers. The verdict: "He had traction, but he didn't understand his own business. That's fatal at any valuation."

A good answer: the share of revenue or users that comes back, by month of sign-up if you have enough history, and the churn rate your plan assumes. If the churn in your model came with a template, assume an investor will notice. Replace it with your own number, or say clearly that it is a guess and what it is based on. See financial model assumptions.

"What are your unit economics?"

Founders dread this one, and it is usually simpler than they fear: what one customer brings in, what it costs to serve them, and what it cost to get them.

Two engineers who were rejected by YC twice, and then by every other accelerator they tried, wrote later that "we also didn't have the metrics to back it up". By their own account they understood their customers better than the investors did, and could not show it in numbers.

A good answer: revenue per customer, gross margin per customer (not only for the company in total), acquisition cost, and how many months it takes to earn that cost back. Four numbers, one sentence each. Gross margin for SaaS walks through the per-customer view.

The question nobody lists: burn and runway

It is rarely on a published list, and it comes up anyway.

In a pitch described on HackerNoon, an investor asked midway through: "So what's your monthly burn?" The founder answered: "Umm… I think my co-founder has that. I haven't looked recently." Nobody was rude, everyone said thanks, and nobody followed up.

A SaaS founder on Reddit had the opposite problem. The runway was solid, but when the investors asked for a walk through the burn: "I basically just narrated a spreadsheet out loud." And then: "They were polite about it. The follow up email was not."

Burn can also be wrong in the founder's own head. A venture builder at Forum Ventures got this text late one night from a pre-seed founder: "I just realized I miscalculated burn, and I need your help ASAP." The raise started four months early, with half a product and no meaningful traction. He raised enough to survive, but on the calendar's terms, not his own.

A good answer: monthly net burn, the month the cash runs out, and two sentences on what drives it, which is usually people. Both founders should be able to say it. The mechanics are in runway and burn rate.

"How much are you raising, and what does it buy?"

"The market is big" answers a different question. The partner is asking how long the money lasts and what will be true when it runs out.

One founder closed a $2.5M seed in January and said it bought 22 months of runway. "By October they were raising an emergency bridge." Spending ran ahead of the model "in ways the model never anticipated."

A good answer: "This round gets us X months, with these hires in these months, to this revenue." And if a hire slips or a price changes, you know which way that month moves.

How to prepare without rehearsing

YC's guide tells founders not to rehearse, and it is right: a scripted answer falls apart at the first follow-up. What helps is one short page of numbers and the reasoning behind each of them.

• Revenue, with one written definition, and growth on that definition
• Where customers come from and what each one costs
• Repeat revenue or retention, and the churn your plan assumes
• Gross margin per customer
• Monthly net burn and the month the cash runs out
• What the round buys: months, hires, and the milestone at the end
• What changes if your next key hire starts three months late

Keep the page where you can see it during the call, as YC suggests. And check that every number on it comes from the same model, so the margin you say in the meeting matches the one the partner sees in the follow-up. If you are earlier than this, why build a financial model early is the place to start.

How Binokl helps

In Binokl the model is built from your products, prices, channels, team and costs, so revenue, margin, burn and the month you run out of cash all come from one place. Move a hire or change a price and every number moves with it, so the answer you give in the meeting is the answer the partner sees afterwards. When they ask for the numbers, you send a link instead of a spreadsheet, and you see when they open it.