Good afternoon, and welcome to the HubSpot's Q1 2025 Earnings Call. My name is Gigi, and I'll be your operator for today. At this time, all participant lines are in listen-only mode, and there will be an opportunity for questions and answers after management's prepared remarks. If you would like to enter the queue for questions, you may do so by dialing star followed by one one on your telephone keypad. I would now like to hand the conference over to Senior Director of Investor Relations, Ryan Burkart. Please go ahead.
Thanks, Operator. Good afternoon, and welcome to HubSpot's First Quarter 2025 Earnings Conference Call. Today, we'll be discussing the results announced in the press release that was issued after the market closed. With me on the call this afternoon is Yamini Rangan, our Chief Executive Officer, Dharmesh Shah, our Co-Founder and CTO, and Kate Bueker, our Chief Financial Officer. Before we start, I'd like to draw your attention to the safe harbor statement included in today's press release. During this call, we'll make statements related to our business that may be considered forward-looking within the meaning of Section 27A of the Securities Exchange Act of 1933 as amended, and Section 21E of the Securities Exchange Act of 1934 as amended.
All statements other than statements of historical fact are forward-looking statements, including those regarding management's expectations of future financial and operational performance and operational expenditures, expected growth, FX movement, and business outlook, including our financial guidance for the second fiscal quarter and full year 2025. Forward-looking statements reflect our views only as of today, and except as required by law, we undertake no obligation to update or revise these forward-looking statements. Please refer to the cautionary language in today's press release and our Form 10-Q, which will be filed with the SEC this afternoon for a discussion of the risks and uncertainties that could cause actual results to differ materially from expectations. During the course of today's call, we'll refer to certain non-GAAP financial measures as defined by Regulation G.
The GAAP financial measure most directly comparable to each non-GAAP financial measure used or discussed, and a reconciliation of the differences between such measures, can be found within our first quarter 2025 earnings press release in the Investor Relations section of our website. Now, it's my pleasure to turn the call over to HubSpot's Chief Executive Officer, Yamini Rangan. Yamini?
Thank you, Ryan, and welcome, everyone. Today, I'll focus on our Q1 2025 results and the key trends driving our performance. Then, I'll highlight the clear momentum we are seeing with AI adoption, how our spring spotlight innovations are accelerating it, and why we believe HubSpot is uniquely positioned to lead and win with AI. Let's dive in. Q1 was a solid start for HubSpot, with revenue growing 18% year-over-year in constant currency. Total customers grew by 19% to over 258,000 globally, fueled by over 10,000 net customer additions in the quarter. I'm also pleased to announce that our Board of Directors has authorized our first-ever share repurchase program with up to $500 million under authorization, a clear signal of the confidence we have in our business and the growth opportunity ahead.
This strength is reflected in our Q1 results, driven by three consistent pillars: platform consolidation, up-market expansion, and strength in customer acquisition down-market. Let's start with platform consolidation. HubSpot's customer platform is becoming the clear choice for businesses looking to drive AI innovation while reducing total cost of ownership with a unified, simpler tech stack. Over 37% of our Pro+ customers by ARR are using four or more hubs, up seven points year-over-year. In Q1, we saw more new Pro+ customers start with our full platform than ever before. This is a clear signal that our platform for strategy is working. In up-market, we continue to see real momentum driven by product innovation and go-to-market execution.
We delivered key enterprise-grade functionality that larger customers need, including journey orchestration in Marketing Hub Enterprise to run sophisticated workflows, enhanced sandbox functionality to support complex implementations, and the launch of three new data centers in Sydney, Oregon, and Montreal. As a result, large deal growth was strong, up 23% year-over-year, with clear momentum among our installed base. Our partners continue to be a key driver up-market, with co-selling up 41% in Q1. In down-market, we see strength in customer acquisition driven by pricing changes and improvements in the free-to-starter conversion. We made our product easy to buy and easy to upgrade, and those changes are a clear tailwind. Free-to-starter conversion is up year-over-year, driven by better onboarding, product improvements, and flexible monthly payment options.
Our Smart CRM and core seat offerings are gaining strong traction, expanding our reach beyond traditional personas to include ops, admin, and finance users who need powerful editing capabilities. 24% of our Pro+ customers on the seats model have purchased additional core seats. It's rewarding to see customers scale with HubSpot, and the consistency of our results shows our platform is delivering real value. Okay, before we move into AI innovation, I want to acknowledge the macro environment. Uncertainty remains the constant. We entered the year with more growth conversations, and while that has not shifted dramatically, we are seeing a sharper focus on value. HubSpot is built for moments like these, and we have a proven playbook to communicate value. As a crafted customer platform, we help businesses consolidate tools, cut costs, and unlock the power of a unified customer view.
Our ease of use and fast time to value allow customers to onboard quickly and see results. With AI embedded across all hubs, we deliver immediate efficiency, and we believe that AI's value is amplified further when companies prioritize driving productivity. In uncertain times, HubSpot is the predictable choice for scaling businesses. Okay, with that, let's shift gears and talk about AI innovation and momentum. Our AI strategy has been clear. We will embed AI into every hub and every part of the platform. One product, one AI-first customer platform, no bolt-ons. We've executed against that strategy by introducing hundreds of embedded features across hubs, launching Copilot to help go-to-market teams get work done faster, and rolling out agents that can do the work for them. We have reinforced the strategy through strategic acquisitions, including Frame AI and Dashworks, to accelerate our roadmap. And that strategy is working.