We make messy market signals make sense.

You are surrounded by market signals, but without the timing layer they are just data without direction. We help B2B SaaS teams turn that chaos into clarity, so they know exactly when to act, win, and grow.

1M+
In funding since 2023
Backed by investors who believe in evidence-based GTM.

We turn complex subscription data into precise, actionable GTM signals.

Our work is not just about numbers or technology. It is about enabling real people to make a difference in their business by knowing who to focus on, when to act, and why it matters.

A shift that changed everything.

The MarketSizer team in Dublin

How it all began.

MarketSizer started out as TamCalc, a tool built by Niall O'Gorman in Dublin with one clear purpose: to help businesses calculate market opportunities.

At the time our focus was on top-down market sizing, but as we kept building we discovered something even more impactful. The challenge was not just sizing markets - it was uncovering actionable, competitive intelligence that teams could use to win, grow, and retain their ideal accounts.

The MarketSizer remote team meeting online

So, we pivoted.

What began as a straightforward market calculator evolved into what might be the largest and most accurate bottom-up subscription data set ever built, powered by more than 20 million subscription signals.

We realised the real challenge was not market sizing - it was knowing exactly when an account was ready to buy, renew, or expand. That is why MarketSizer is built to give GTM teams the timing edge they have never had before.

Four principles that guide every decision.

Evidence over assumptions

Every claim we make is backed by real subscription data and inspectable signals - not guesses or vanity metrics.

Transparency by default

Every score and signal comes with the evidence behind it. You should never have to trust a black box.

Quality over volume

A hundred qualified opportunities beat ten thousand unqualified leads. We focus on signals you can actually act on.

Customer success is ours

We only win when our customers close more deals. That alignment shapes how we build, support, and price.

Meet our team.

A small, remote-first crew across Europe, building subscription intelligence for GTM teams who want to act on evidence, not gut feel.

Niall O'Gorman

Niall O'Gorman

Founder & CEO

LinkedIn
Benjamin Duval

Benjamin Duval

Data Scientist

LinkedIn
Razvan Vierasu

Razvan Vierasu

Market Sizing Specialist

LinkedIn
Jose Felipe Sánchez

Jose Felipe Sánchez

Product Analyst - Data Insights

LinkedIn
Vedhas Shejwalkar

Vedhas Shejwalkar

Sales & Client Success

LinkedIn
Svea Schüler

Svea Schüler

Strategic Initiatives Coordinator

LinkedIn
Andrea O'Donnell

Andrea O'Donnell

Financial Controller

LinkedIn
Iggy

Iggy

Chief Happiness Officer

Working at MarketSizer.

Your market is mapped.
Your opportunities are waiting.

15 minutes. No commitment. We'll show you the accounts in your market that are actively evaluating right now.

No credit card · Tailored to your ICP · Live data, not a slide deck