Free · No login · 12 weekly challenges · 23 frameworks · Updated Nov 2026

The 12-week YC challenge: run a Y Combinator batch on your own

What happens inside YC each week of its three months, and the same week here, as a challenge: the framework partners teach, one hard task to finish, the questions they ask at office hours and a weekly update with your one number.

Start the challengeSee the 12 challengesThe YC deal and batch, explained →

YC does not publish a day-by-day calendar. We rebuilt the structure from YC’s pages, partner talks and founders’ accounts; every claim is labelled documented or reported. Unofficial, not affiliated with Y Combinator.

Weekly challenges
12
Assignments
66
Office-hours questions
62
12 weeks · one challenge a week

Do you want to start the challenge?

Run your own YC batch: the same 12-week rhythm, one hard, specific challenge each week, and a weekly update with your one number. You pick the dates. Nothing to sign up for; it is saved on this device.

  • Each week: what happens inside YC, the framework partners teach, and your challenge
  • Every Monday: your one number and a short update
  • Week 12: your own Demo Day pitch
Read week 1 first
What repeats every week

The rhythm of a YC week

The batch is not a school. YC events take a few hours a week; the rhythm around them is what founders copy. Each part is labelled by where it comes from.

  1. Monday
    Your number and a weekly update

    Write down the one number you are growing and send a short update: number, what you did, what you learned, your ask. The week page builds it for you.

    This program’s routine
  2. Every week
    Fixes at a resolution of a week

    Graham describes founders trying fixes “at a resolution of a week or less” and reporting results at office hours, so a wrong guess shows up fast.

    Paul Graham’s adviceWhat I’ve Learned from Users (2022)
  3. Every two weeks
    Group office hours

    Partners meet companies from your group in sections of 6–10. One-on-one office hours are available “as often as founders want”. Here you answer the partner’s questions on each week page.

    Documented by YCycombinator.com/about
  4. Every week
    A talk from someone who has done it

    YC invites a well-known founder or investor to speak each week, off the record. Each week page here has the YC talk for that week’s topic.

    Documented by YCycombinator.com/about
  5. The rest of the week
    Build and talk to users

    YC’s FAQ says following every recommended activity takes “a few hours per week”. The rest is building the product and talking to users.

    Documented by YCycombinator.com/faq
Phase 1 of 3 · Weeks 1–4

Build and launch

Pick the one number you will grow, talk to users and get a first version into real hands.

  1. 1Week 1 · Kickoff and your one numberThe one-number challengeNot startedBy Sunday, write a precise definition of your primary metric, record today’s value, set a goal for the end of week 12 and the weekly rate it needs, and send weekly update #1 to at least two people.At YC: YC’s own pages describe the start of the batch: a 3-day, in-person kickoff in the first few weeks, where founders meet each other, their group partners and the YC team.Assignments0/5Choose one primary metric and set a goal for itThe weekly update
  2. 2Week 2 · Talk to usersThe 10 conversations challengeNot startedHold 10 conversations of at least 15 minutes with people who have the problem you want to solve, using only questions about their life, not your idea. Then rank the problems you heard.At YC: YC’s 2017 pocket guide, written up by Geoff Ralston, says "The most important tasks for an early stage company are to write code and talk to users." Founders report hearing the same thing in person.Assignments0/6The five questions, and the three mistakesFrom notes to a decision
  3. 3Week 3 · Plan and build the MVPThe 7-day v1 challengeNot startedWrite a one-page spec for the top problem from week 2, cut it until it fits seven days, and by day 7 have at least three people from your week 2 conversations use it for real.At YC: YC’s FAQ says that on average 40% of the companies it funds in each batch are "just an idea".Assignments0/6How to plan an MVP: timebox, write it down, cut
  4. 4Week 4 · LaunchThe public launch challengeNot startedLaunch v1 publicly in at least two places where your users already gather, reply to every comment the same day, and get 10 new users who are not friends or family.At YC: YC’s "What Happens at YC" page says YC helps founders present their product to users and the press, including preparing for launches on Product Hunt and Hacker News.Assignments0/6Launch again and again: the launch ladderWrite a launch post Hacker News readers will respect
Phase 2 of 3 · Weeks 5–8

Grow

Recruit users by hand, grow every week and fix what stops people coming back.

  1. 5Week 5 · First customers by handThe 20 by hand challengeNot startedBy Sunday, recruit 20 new users or customers yourself, one at a time. Each one is contacted personally by a founder and set up by you, on a call or in person. No ads, no mass emails, no launch posts.At YC: YC’s own pocket guide of advice (Geoff Ralston, 2017) says that once you have launched, do things that don’t scale and get your first customer by any means necessary.Assignments0/5The founder sales funnel, worked backwards from your goalRecruit, set up, delight: do things that don’t scale
  2. 6Week 6 · Retention and product-market fitThe retention truth challengeNot startedBuild a weekly cohort retention table from your real usage data, and send the “very disappointed” survey to everyone who has used the core of your product. By Sunday, name the group of users who would be very disappointed and what they have in common.At YC: YC’s pocket guide of advice (Geoff Ralston, 2017) tells founders to choose one or two key metrics very early, and says growth makes little sense before product-market fit; the usual result is poor retention.Assignments0/5The cohort retention curveThe “very disappointed” test
  3. 7Week 7 · Prioritise and hit your numberThe one-number weekNot startedSet this week’s target at 5–7% above last week’s value of your one number. Work only on tasks you graded high impact, and cut one recurring distraction for the whole week.At YC: YC’s “What Happens at YC” page says partners hold group office hours every two weeks and one-on-one office hours as often as founders want, and that what founders discuss depends on their stage and where they are in the batch.Assignments0/5Real vs fake progress, graded by impact and complexityA weekly growth target, checked at the resolution of a week
  4. 8Week 8 · Pricing and first revenueThe 10 prices challengeNot startedQuote a specific price to 10 current or likely users this week, in a live conversation, and get at least one to pay or sign a written commitment to pay: a payment, a deposit, an invoice they accept or a paid pilot with a start date.At YC: In YC’s talks and videos, partners keep returning to one point.Assignments0/5The pricing thermometer and the 10-5-20 ruleThe value equation for B2B pricing
Phase 3 of 3 · Weeks 9–12

Raise and Demo Day

Know if you are default alive, build your pitch and investor list, and present.

  1. 9Week 9 · Default alive and your investor listThe runway and 30 investors challengeNot startedBy Sunday, work out from your real bank balance, costs and revenue whether you are default alive, and the month you either turn profitable or run out of cash. Then build a list of 30 real, named investors ranked by expected value, each with a way to reach them.At YC: YC funds every company the same way before the raise starts.Assignments0/6Default alive or default deadHow a seed round works: amount, SAFE, cap, list, close
  2. 10Week 10 · The pitch: two clear sentencesThe repeat-it-back challengeNot startedWrite a two-sentence description of your company. Say it to 5 people who don’t work in your field, one at a time, and ask each to explain it back in their own words. Rewrite after every failure until all 5 can repeat it.At YC: YC works on the pitch long before Demo Day.Assignments0/5The seven pitch questions and the two-sentence descriptionKevin Hale’s clarity rules: legible, simple, obvious
  3. 11Week 11 · Demo Day rehearsalThe 60-second, three-round challengeNot startedWrite a Demo Day pitch that fits in 60 seconds with one slide, record it on your phone, and run three rounds of feedback, rewriting and re-recording after each round.At YC: YC’s current pages do not say how long a Demo Day pitch is or how rehearsals run.Assignments0/6The Demo Day presentation: vertebrae, structure, deliveryOne slide that is legible, simple and obvious, then rehearse
  4. 12Week 12 · Demo Day and afterThe Demo Day and retrospective challengeNot startedGive your 60-second pitch live to a room or call of at least five investors, mentors or founders, or publish it as a public video. Follow up with everyone who showed interest within 24 hours, and send a 12-week retrospective update to everyone who has followed your weekly updates.At YC: YC’s Demo Day page says the Fall 2026 Demo Day is on Wednesday, December 2, and that the batch presents to an invite-only audience of about 1,500 investors and media; YC’s Demo Day FAQ, checked the same day, says about 1,000, so YC’s own pages disagree.Assignments0/6After Demo Day: follow up the same day, close fast, get back to workJudge investors by what they do, not what they say
Your one number · saved on this device

Growth tracker

Enter your number every week (the weekly update on each week page fills this in for you). The shaded band shows 5–7% weekly growth from your first week, the rate Paul Graham calls good in ‘Startup = Growth’ (2012).

Average weekly growth
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Your number5–7% a week from your first weekPaul Graham, ‘Startup = Growth’ (2012): 5–7% a week is a good rate early on; 10% is exceptional.
WeekYour numbervs last week
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23 frameworks · explained in full on each week

Every framework in the program

The methods YC partners and Paul Graham teach, each credited and worked through with an example.

The YC batch: questions people ask

What is the 12-week YC challenge?

A free, self-run version of a Y Combinator batch. Each of the 12 weeks explains what happens inside YC around that point, teaches the framework YC partners use then, and sets one hard, specific challenge (for example, ten conversations with potential users, or a launch). You send yourself a weekly update with your one number, answer the questions a partner would ask at office hours, and finish with your own Demo Day pitch. You choose the start date; your progress is saved on your device, with no login.

Is this the real YC curriculum?

No. YC does not publish a week-by-week curriculum. We rebuilt the structure from what YC itself documents (a kickoff, group partners, group office hours every two weeks, weekly talks, Demo Day), from YC partners’ public talks and from founders’ own accounts of their batch. Each week labels what is documented by YC and what is reported by founders, with sources. This page is unofficial and not affiliated with Y Combinator.

What happens in a YC batch?

According to YC’s “What Happens at YC” page, the batch opens with an in-person kickoff, startups are split into groups led by partners and into sections of 6–10 companies, partners hold group office hours every two weeks and one-on-one office hours as often as founders want, a guest speaks every week off the record, and the program ends with Demo Day in front of investors. Most of the week is left for building and talking to users.

How long is YC?

About three months. Since 2025 YC runs four batches a year (Winter, Spring, Summer and Fall), each ending in Demo Day. This program follows the same length: 12 weeks, from picking your one number to presenting.

Do I need a co-founder to do this program?

No, you can run it alone. But Paul Graham lists having a single founder as the first of “The 18 Mistakes That Kill Startups” (2006), so the program includes looking for a cofounder. The cofounders lesson in the Paul Graham course covers how to find and test one.

What is group office hours?

At YC, it is a session every two weeks where partners meet a small set of companies from your group together (YC groups companies in sections of 6–10). Here, each week page lists the questions a partner would ask at that stage, with space to write your answer and a note on why they ask it. You can run it with friends doing the program by sharing your answers every two weeks.

12 challenges · 12 weekly updates · 1 Demo Day

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