Total addressable market represents the revenue potential for a product assuming a business has unlimited resources and all eligible customers in a target market are acquired. Total addressable market can be a big challenge for startups.

As an operator, I’ve designed market sizing and go-to-market approaches at several early and late-stage companies. In 2014, I was responsible for launching Twitter’s mobile app product suite and business unit in EMEA and in 2017 launched Stripe’s startup partnership strategy.

The Top-Down Trap

A common failure-mode for building a TAM is adopting a top-down analysis—selecting a market value from a Gartner or IDC report and assuming you can capture even a small share like 0.5% or 1%.

Using this method keeps you at a detrimental distance from factors like addressability, product-market fit, segmentation, and pricing. It sounds impressive in a pitch deck but tells you nothing about how you’ll actually acquire customers.

The classic “if we capture just 1% of a $100 billion market” slide is a red flag to experienced investors. It suggests the team hasn’t done the hard work of understanding their actual path to customers.

Bottom-Up is Better

Teams that understand TAM risks and opportunities always bias towards a bottom-up methodology.

A bottom-up approach forces you to answer real questions:

• Who exactly are your customers?
• How many of them exist?
• What will they pay?
• How will you reach them?
• What’s your realistic close rate?

This granular thinking creates a more defensible market size estimate and, more importantly, gives you a roadmap for actually capturing that market.

TAM as a Strategic Tool

In early-stage companies, TAM identification is a common trait of breakout companies whilst also creating a safety-net to pivot towards new segments where required.

Understanding your market at a granular level helps you:

1. Prioritize segments - Not all customers are equally valuable or accessible. Focus on the segments where you can win.

2. Price correctly - Understanding willingness to pay across segments helps you optimize pricing.

3. Identify expansion opportunities - Once you’ve won a beachhead, where do you go next?

4. Spot pivot opportunities - If your initial market isn’t working, granular TAM analysis shows you adjacent opportunities.

SAM and SOM Matter More

While TAM gets the headlines, your Serviceable Addressable Market (SAM) and Serviceable Obtainable Market (SOM) are what really matter for planning.

• TAM: Total market demand for your category
• SAM: The portion you can realistically serve given your product, geography, and go-to-market
• SOM: What you can realistically capture given competition and resources

For an early-stage startup, SOM is your actual target. Don’t get distracted by impressive-sounding TAM numbers.

The Real Question

The question isn’t “is your market big enough?” It’s “do you have a credible path to capturing meaningful share of a meaningful market?”

A $1 billion TAM with a clear path to 10% share is more valuable than a $100 billion TAM where you’re guessing at 0.1%.

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Is the juice worth the squeeze? Only if you’ve done the hard work of understanding your market from the bottom up. The TAM exercise isn’t about impressing investors with big numbers—it’s about understanding your actual opportunity and path to capturing it.

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