Your market sizing tells investors that the problem you’re solving is worth solving. It’s how you show the size of the prize: that there’s real financial upside if your startup succeeds.
The market size slide comes right after the problem and before your solution. It’s important for communicating why now is the right time and why your idea matters at scale. If the market is too small or your analysis seems dubious, it can raise immediate doubts.
Two strong formats for market size slides
There are different ways to visualize market size depending on your data, story, and audience. The best decks make it clear how big the market is, and how much of it your startup can realistically capture. Here are two strong formats to consider, both included in the PowerTools Startup Pitch Deck Template. We’ll also walk through an example of how to calculate TAM, SAM, and SOM in practice.
1. TAM, SAM, SOM
This is the classic approach to market sizing. It breaks down the market into three parts (for our example let’s say you’re selling a productivity tool to freelancers).
- TAM: Total Addressable Market — the total demand for your category.
- Example: Start with the total number of freelancers worldwide (e.g., 1 billion) and multiply by their average annual spend on productivity tools (e.g., $100/year), giving you a TAM of $100B.
- SAM: Serviceable Available Market — the segment you’re targeting.
- Example: Narrow the TAM to US-based freelancers (e.g., 10 million), resulting in a SAM of $1B.
- SOM: Serviceable Obtainable Market — the realistic portion you can capture in the near term.
- Example: Based on your distribution, pricing, and customer acquisition strategy, you might estimate capturing 2% of the SAM, resulting in a SOM of $20M.
This bottom-up approach helps validate that your business opportunity is real and that you’ve thought through your target customer base and pricing structure.
Example voiceover for a startup building bookkeeping software for freelancers in the US:
“The global bookkeeping software market is $25B. Our target is US-based freelancers, which we estimate to be a $2B segment. With our distribution channels and pricing model, we believe we can capture $150M of that over time.”
2. Growth Trend
This version focuses on how the market is evolving over time. It’s a good fit if you’re entering a fast-growing or emerging market and want to emphasize momentum. Pairing a bar chart with your SOM estimate helps show both opportunity and timing.
Example voiceover for a a startup offering AI tools for the construction industry:
“Construction tech spending is growing at 14% year-over-year, expected to hit $30B by 2028. Within that, we’re targeting small and mid-sized firms investing in AI automation—a $4B slice of the market we believe we can penetrate with vertical-specific tools.”
Common Mistakes to Avoid
- Top-down estimates only. Avoid saying “we’ll capture 1% of a giant market” without showing how.
- No explanation. Always include how you calculated your numbers and your assumptions.
- Too broad. Define your target segment clearly—general market stats won’t cut it.
- Inconsistent math. Make sure your SOM doesn’t magically exceed your SAM.
A great market size slide gives investors confidence that the problem matters and that your business can scale. It’s not just about the big number, it’s about showing you understand your space and have a realistic plan to win a meaningful piece of it.
