How to Find the Right Market for Your SaaS: TAM, SAM, SOM Made Simple

If you're building a SaaS product, you’ve probably heard that you need to “define your market.” But what does that actually mean and how do you do it, especially if you're a technical founder without a marketing team?

That’s where TAM, SAM, and SOM come in. These three simple but powerful acronyms can help you:

• Focus your marketing efforts
• Set realistic growth targets
• Avoid wasting time pitching to the wrong audience

The best part? You don’t need an MBA or a data team to figure this out.

In this post, we’ll break downwhat TAM, SAM, and SOM mean in plain language, why they’re important for early-stage SaaS businesses, and how to estimate them using simple tools. We'll walk through real-world examples (especially from small B2B tools and indie developers), highlight common mistakes, and finish with a simple worksheet you can adapt for your own product.

TAM, SAM, SOM: What They Mean (Without the Buzzwords)

A calendar scheduling toolbuilt specifically foronline fitness coacheswho do 1-on-1 video sessions.

Here’s how you could think about your market:

TAM: Total Addressable Market

This is the dream. TAM is themaximumrevenue you could make if every possible person or business whocoulduse your product actually bought it.

• For your calendar scheduling tool: TAM might include all fitness professionals worldwide who offer personal coaching services.
• It’s your biggest market size number; helpful for long-term vision and investors.

Let’s say there are ~30 million fitness professionals globally. This includes gym trainers, yoga instructors, online coaches, etc.
If you charge $120/year, your TAM = 30M x $120 = $3.6 billion/year

SAM: Serviceable Available Market

This is the reality check. SAM is the part of the TAM that your product can actually serve based on its features, pricing, and language support today.

• For example,coaches who deliver their services online, speak English, and use video calls like Zoom or Google Meet.
• It narrows things down to a realistic audience.

Let’s say that’s around 3 million coaches who deliver their services online, speak English and use video calls globally. These are people your product is currently built for.
Your SAM = 3M x $120 = $360 million/year

SOM: Serviceable Obtainable Market

This is your starting line. SOM is the slice of the SAM that you can realistically reach with your current team, budget, and marketing.

• Maybe you’re a solo indie dev. Your SOM might be the coaches you can realistically reach right now with your current team and marketing efforts. Say,U.S.-based coaches actively looking for scheduling tools.

Based on your budget and channels (e.g. Meta ads, Reddit, or niche directories), maybe you could target 15,000 coaches in year one who are U.S.-based and actively looking for scheduling tools
Your SOM = 15K x $120 = $1.8 million/year

Here’s a visual to keep in mind:


Why TAM/SAM/SOM Matter for SaaS Founders

Early-stage SaaS startups often fall into a dangerous trap: trying to sell to everyone.

But when you define TAM/SAM/SOM, you:

• Stay focused on the customers who matter mostright now
• Set realistic growth targets
• Avoid building features no one in your reachable market wants
• Make smarter decisions about marketing channels

It's not just about sizing the market. It's about knowing where to start and where to grow next.

How to Estimate TAM/SAM/SOM Without a Data Team

Here’s a step-by-step guide you can follow using basic research and simple math.

Step 1: Define Your Ideal Customer

Start with a clear customer profile. Who is your product built for right now?

Example:"Online fitness coaches in the U.S. who run 1-on-1 video sessions and need a simple scheduling tool."

Be specific: niche, location, language, delivery method, tech tools used, etc. Anything that narrows it down.

Step 2: Estimate Your TAM (Total Addressable Market)

Ask yourself: If every possible customer who could use a tool like this actually bought it, how big is that market?

Use sources like:

• Google: “number of fitness coaches worldwide”
• LinkedIn or job boards
• Statista or industry reports

Example:Let’s say there are30 million fitness professionalsglobally (trainers, yoga instructors, etc.).

You charge $10/month → $120/year

TAM = 30M x $120 = $3.6 billion/year

That’s the total dream market. You won’t reach them all, but this shows the upper ceiling.

Step 3: Narrow to SAM (Serviceable Available Market)

Now filter it based on who your product can actually serve today.

Let’s say your scheduling tool:

• Is in English only
• Supports Zoom and Google Meet
• Is designed for independent coaches (not gym chains)

From that 30M:

• 5M are independent online coaches
• 60% speak English

SAM = 5M x 60% = 3M potential users → SAM Revenue = 3M x $120 = $360 million/year

This is yourrealistic target audiencebased on your current product.

Step 4: Define Your SOM (Serviceable Obtainable Market)

Now ask: How many of those people can we realistically reach in the next 12–18 months with our current team and channels?

You’re a solo founder or small team. You’re marketing on Instagram, Reddit, Product Hunt, and a few fitness communities. You’re focusing on the U.S. first.

Let’s say you can reach about 0.5% of your SAM in year one.

SOM = 3M x 0.5% = 15,000 potential users → SOM Revenue = 15K x $120 = $1.8 million/year

That’s your short-term realistic opportunity. This is what you can base your early growth plans on.

Recap: TAM, SAM, SOM for Your Fitness SaaS Example


Real-World Example: A B2B SaaS Tool

Let’s look at a simple B2B tool:a scheduling app for online coaches.

• TAM: All coaches who do 1:1 client sessions globally (~50M coaches)
• SAM: Coaches who speak English, work online, and use Zoom (~5M coaches)
• SOM: U.S.-based online coaches actively searching for scheduling apps (~20K coaches)

You build your landing page and onboarding specifically for that 20K. When you grow, you can expand to the broader SAM, then TAM.

⚠️ Common Mistakes to Avoid

Founders often get tripped up when estimating TAM/SAM/SOM. Here are five common pitfalls and how to avoid them:

1. Using TAM as Your Short-Term Goal

• The mistake:"Our market is worth $3 billion; if we get just 1% of that, we’ll be rich!"
• Why it’s a problem:TAM is your long-term vision, not a realistic goal for the next 12–24 months. Investors might ask about TAM, but your actual growth depends on how well you can reach your SOM.
• What to do instead:Focus your roadmap and go-to-market strategy around your SOM.

2. Skipping SAM Entirely

• The mistake:Jumping from TAM straight to SOM without thinking through who your product actually serves right now.
• Why it’s a problem:Without SAM, you’re missing the middle step that filters out users you can’t serve yet (due to language, pricing, integrations, etc.).
• What to do instead:Be brutally honest about who your product is ready for today, SAM helps you prioritize.

3. Assuming the Market Is Growing Fast

• The mistake: "This market is exploding; we’ll grow just by showing up!"
• Why it’s a problem: Not all markets grow at the same pace. Some are shrinking. Some are crowded. Assuming growth without validation can set you up for disappointment.
• What to do instead: Validate with real data (Google Trends, niche forums, LinkedIn job listings, etc.) or by talking to actual customers.

4. Ignoring Distribution Limits

• The mistake: Estimating SOM as if you had unlimited reach.
• Why it’s a problem: Just because 1 million people could use your product doesn’t mean you can reach them with your current team, budget, or channels.
• What to do instead: Base SOM on your current reach via ads, communities, cold emails, or content, and estimate conservatively.

5. Overestimating Pricing

• The mistake: Using your dream pricing in all market size calculations.
• Why it’s a problem: In early-stage SaaS, you often start with discounts, lifetime deals, or low entry plans. Using full-price assumptions makes your TAM/SAM/SOM look inflated.
• What to do instead: Use realistic, average revenue per user (ARPU) based on early customers or competitors.

Simple Worksheet Template

You can use this quick worksheet to sketch your TAM/SAM/SOM in under 30 minutes:


Summary Checklist

Before you move on, ask yourself:

• Have I defined my ideal customer clearly?
• Did I look up rough market size data from credible sources?
• Did I narrow my SAM based on product fit?
• Is my SOM based on actual reach and budget?
• Am I using these numbers to focus, not just impress investors?

You don’t need to be a market research expert to make smart, focused decisions. With just a bit of research and honest thinking, you can figure out:

• Who you're really building for,
• How big the opportunity is,
• And where to start today.

✨Start with SOM— the users you can reach right now.

🚀Grow into your SAM— the broader audience your product serves as it evolves.

🌍Dream about your TAM— the full potential you can unlock over time.

That’s not just market sizing. It is smart, focused SaaS marketing. Start small. Stay sharp. Build with purpose.

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