Ideas & Opportunity

How big does my market need to be for this to be a real business?

A starting point

It depends on your ambition: a bootstrapped indie business can thrive in a market worth a few million, but a venture-backed one needs a market that can plausibly reach hundreds of millions to a billion in revenue. Don't confuse a huge TAM slide with a real reachable market; investors care about the wedge you can actually win first. Size the specific segment you can serve now, not the fantasy total.

Go deeper

Read

📄 Article
Freemium Intermediate

How to identify your ideal customer profile (ICP)

From Lenny's Newsletter by Lenny Rachitsky ~15 min read

Why we picked it

Market size is meaningless until you know exactly who you're for, and Lenny turns that into a concrete, repeatable ICP exercise from real B2B operators. It grounds your SAM in an actual customer definition instead of a fuzzy segment.

  • Define the specific customer you serve before you size the market, not after.
  • A sharp ICP makes your bottom-up market math credible and your GTM focused.
  • Narrowing 'who it's for' is what makes a small beachhead winnable.
Open lennysnewsletter.com →
📄 Article
India Free Advanced

Sajith Pai on the Indus Valley Report & the Indian market (India1/2/3)

From sajithpai.com by Sajith Pai (Blume Ventures) essays + annual report

Why we picked it

The eChai edge for market sizing: Sajith Pai's India1/India2/India3 framework and the Indus Valley report are the sharpest public analysis of who in India actually has money to spend. Essential before you slap '1.4 billion people' on a TAM slide.

  • India's real spendable market (India1) is roughly 100 million people, not 1.4 billion.
  • Segment the Indian market by disposable income before sizing it, or your SAM is fiction.
  • Build for the segment that can actually pay, and translate US theses to Indian wallets carefully.
Open sajithpai.com →
📄 Article
Free Intermediate

Market Size: What is TAM, SAM, & SOM?

From carta.com by Carta ~12 min read

Why we picked it

A clear, no-nonsense primer on the three market-size numbers every founder gets asked about, with the bottom-up method that actually holds up in front of investors. Pick this over the SEO listicles because it comes from a platform that lives inside real cap tables and fundraises.

  • TAM is the whole category, SAM is what you can realistically serve, SOM is what you can win near-term.
  • Build the numbers bottom-up (customers times price), not top-down percentages of a giant number.
  • A defensible SOM matters more to investors than an impressive TAM slide.
Open carta.com →

People also ask

What are TAM, SAM, and SOM and how do I actually calculate them? TAM is everyone who could ever use your category, SAM is the slice your product and geography can actually serve, and SOM is the realistic chunk yo... Intermediate 2 resources → Why does 'why now?' matter so much for a startup idea? Most great startups ride a change that just made something newly possible or newly cheap: a new technology, regulation, behaviour, or cost curve. I... Intermediate 3 resources → My market is small right now but growing fast. Is that a problem? A small, fast-growing market often beats a big, flat one, because you can ride the growth instead of stealing share in a knife fight. Investors and... Intermediate 3 resources → How do I size a market for India specifically when data is messy? Ignore the '1.4 billion people' headline; the real spendable market in India is a fraction of that. Use frameworks like Blume's India1/India2/India... Advanced 3 resources → Should I worry that my market is already crowded with competitors? A crowded market is proof that people will pay, which is a good sign, not a red flag. What kills you is entering a crowded market with no sharp wed... Intermediate 3 resources → What makes an Indian startup idea work when the market is so price-sensitive? In India, a great idea usually means being dramatically better, not marginally better; the switch has to be so obvious that people change behaviour... Intermediate 3 resources →