Thanks, Mark, and good afternoon, everyone. Let's begin with our segment results. All comparisons are on a year-over-year basis unless otherwise noted.
Our community across the family of apps continues to grow. We estimate more than 3.5 billion people used at least one of our family of apps on a daily basis in December. Q4 total family of apps revenue was $58.9 billion, up 25% year over year. Q4 family of apps ad revenue was $58.1 billion, up 24% or 23% on a constant currency basis.
In Q4, the total number of ad impressions served across our services increased 18%. Impression growth was healthy across all regions, driven primarily by engagement and user growth and to a lesser degree ad load optimizations. The average price per ad increased 6% year over year, benefiting from increased advertiser demand largely driven by improved ad performance.
Family of apps other revenue was $801 million, up 54%, driven by WhatsApp paid revenue growth as well as MetaVerified subscriptions. Within our Reality Labs segment, Q4 revenue was $955 million, down 12% year over year. As we noted on the last call, the year-over-year decline in Reality Labs revenue is due to us lapping the introduction of Quest 3s in 2024 as well as retail partners procuring Quest headsets during the year. Added this year.
Particularly AI talent. Legal expense growth was due to both lapping legal accrual reversals in '24 and charges recorded in Q4 2025. Infrastructure expense growth was driven by higher depreciation, cloud spend, and other operating expenses. We ended Q4 with over 78,800 employees, up 6% year over year, driven by hiring in priority areas of infrastructure, Meta Superintelligence were $22.1 billion, driven by investments in data centers, servers, and network infrastructure. Free cash flow was $14.1 billion. We ended the quarter with $81.6 billion in cash and marketable securities and $58.7 billion in debt. Turning now to the business performance. There are two primary factors that drive our revenue performance.
Our ability to deliver engaging experiences for our community, our effectiveness at monetizing that engagement over time. Product efforts on both feed and video surfaces. The optimizations we made in Q4 drove a 7% lift in views of organic feed and video posts on Facebook. Resulting in the largest quarterly revenue impact from Facebook product launches in the past two years. We're continuing to increase the freshness and originality of content recommendations as well. On Facebook, our systems are surfacing over 25% more reels published that day than the prior quarter. On Instagram, we grew the prevalence of original content in the US by 10 percentage points in Q4 with 75% of recommendations now coming from original posts. Threads is also seeing strong momentum again, benefiting from recommendation improvements. The optimizations we made in Q4 drove a 20% lift in Threads time spent. Turning to 2026, we see a lot of opportunity to drive additional gains.
This includes scaling the complexity and amount of training data we use in our models, while continuing to make our systems more responsive to people's real-time interests. We're also focused on incorporating LLMs to understand content more deeply across our platform, which will enable more personalized recommendations. Another big area of investment this year is developing the generation of our recommendation systems. We have several big bets on this front, including building new model architectures from the ground up that will work on top of LLMs, leveraging the world knowledge and reasoning capabilities of an LLM to better infer people's interests. Beyond improvements to our recommendation systems, we expect to use the models developed by Meta Superintelligence Labs to deliver compelling and differentiated AI products.
One area we're already seeing promise is with AI dubbing of videos into local languages. We are now supporting nine different languages with hundreds of millions of people watching AI-translated videos every day. This is already driving incremental time spent on Instagram, and we plan to launch support for more languages over the course of this year. We are also seeing strong traction with our media creation tools. Nearly 10% of the reels people view each day are now created in our Edits app, almost tripling from last quarter. Within Meta AI, the number of daily actives generating media tripled year over year in Q4. This year we expect to advance the capabilities of our underlying media generation models and ship new features to further enhance the product experience. Another area we're focused on for Meta AI is personalization. We're seeing in our early testing that personalized responses drive higher levels of engagement. And we expect to significantly advance the personalization of Meta AI this year. This dovetails with our investments in content understanding, which will enable our systems to develop a deeper understanding of each person's interests and preferences while also identifying the most relevant content across our platform to pull into responses. Turning to the second driver of our revenue performance, increasing monetization efficiency.
The first part of this work is optimizing the level of ads within organic engagement. Load increases. We also continue to make progress on bringing ads to our newer services. Within Threads, we're beginning to expand ads to all remaining countries this month, including the UK, European Union, and Brazil. On WhatsApp, we expect to complete the rollout of ads and status throughout the year with the level of ads remaining low in the near term while we follow our standard approach of optimizing ad formats and performance before ramping inventory.
Moving to the second part of increasing monetization efficiency, improving performance for the businesses who use our tools. We're seeing very strong results from the ad performance investments we made throughout 2025 with year-over-year conversion growth accelerating through the fourth quarter. We expect the set of investments we're making in 2026 will enable us to drive further gains as we continue to integrate AI across all layers of the marketing and customer engagement funnel. The first area is our ad system, where we're continuing to scale the data complexity and compute we use in our future ranking models to deliver performance gains.
As we scale up our foundational ads models like GEM, we are also developing more advanced models to use downstream of them at runtime for ads inference. In Q4, we launched a new runtime model across Instagram feed stories, reels, resulting in a 3% increase in conversion rates in Q4. We continue to progress on our model unification efforts under Lattice as well. After seeing strong success with the consolidation of Facebook feed and video models in 2025, in Q4, we consolidated models for Facebook stories and other surfaces into the overall Facebook model. This, along with a series of back-end improvements, drove a 12% increase in ad quality. And in 2026, we expect to consolidate more models than we had in the prior two years as we continue to evolve our systems towards running a smaller number of highly capable models. Moving to the next area, ads products.
Continue investing in ways to help businesses leverage AI to reduce the friction of setting up and optimizing an ad campaign. In Q4, we started testing our Meta AI business assistant with advertisers, which helps with tasks like campaign optimization and account support. In the coming months, we'll make it available to more advertisers so each business has an AI assistant they can chat with that remembers their business's goals and provides personalized recommendations on how to improve performance. Another area we're deploying AI to improve performance is ad creative. The work I'll cover is business messaging, where we're seeing strong momentum across our portfolio of solutions. Click-to-message ads revenue growth accelerated in Q4 with the US up more than 50% year over year, driven by strong adoption of our website-to-message ads, which direct people to a business's website for more information before choosing to launch a chat. Paid messaging within WhatsApp continues to scale as well, crossing a $2 billion annual run rate in Q4. Finally, we're seeing good early traction with our business AIs in Mexico and the Philippines, with over 1 million weekly conversations between people and business AIs now happening on our messaging platforms. This year, we will expand the availability of our business AIs to more markets, while also extending their capabilities so they not only answer questions on topics like product availability but can help people get things done right within WhatsApp. We speak a lot about how AI is improving our products, but I'd like to take a moment to give an update on how it's changing the way we work.
Mark mentioned our focus on making Meta a place where individuals can have significant impact. A big focus of this is to enable the adoption and advancement of our AI coding tools where we're seeing strong momentum. Since the beginning of 2025, we've seen a 30% increase in output per engineer, but the majority of that growth coming from the adoption of agentic coding, which saw a big jump in Q4. We're seeing even stronger gains with power users of AI coding tools, whose output has increased 80% year over year. We expect this growth to accelerate through the next half. Next, I would like to discuss our approach to capital allocation. We have significant opportunities to improve our core business in 2026. We plan to continue to prioritize investing in the business to support these opportunities recommendation training workloads. In addition to the inference workloads it currently runs. More broadly, as we invest in infrastructure to meet our business needs, we continue to prioritize maintaining long-term flexibility so we can adapt to how the market develops. We're doing so in several ways, including changing how we develop data center sites, establishing strategic partnerships, contracting cloud capacity, and establishing new ownership structures for some of our large data center sites. We have a strong net cash balance and expect our business will continue to generate sufficient cash to fund our infrastructure investments in 2026, which is reflected in our expectations. Nonetheless, we will continue to look for opportunities to periodically supplement our strong operating cash flow with prudent amounts of cost-efficient external financing, which may lead us to eventually maintain a positive net debt balance.
Moving to our financial outlook. We expect our first quarter 2026 total revenue to be in the range of $53.5 billion to $56.5 billion. Our guidance assumes foreign currency is an approximately 4% tailwind to year-over-year total revenue growth based on current exchange rates.
Turning to the expense and CapEx outlooks. Expect full-year 2026 total expenses to be in the range of $162 to $169 billion. The majority of expense growth will be driven by infrastructure costs, which includes third-party cloud spend, higher depreciation, and higher infrastructure operating expenses. The second largest contributor to total expense growth is compensation driven by investments in technical talent. This includes 2026 hires to support our priority areas, particularly AI, as well as a full year of expenses from 2025 hires. At a segment level, we expect expense growth to be driven by the family of apps with Reality Labs operating losses remaining similar to 2025 levels. Anticipate 2026 capital expenditures, including principal payments on finance leases, to be in the range of $115 to $135 billion with year-over-year growth driven by increased investment to support our Meta Superintelligence Labs efforts and core business. Despite the meaningful step-up in infrastructure investment, in 2026, we expect to deliver operating income that is above 2025 operating income. Absent any changes to our tax landscape, we expect our full-year 2026 tax rate to be 13% to 16%. Finally, we recently aligned with the European Commission on further changes to our less personalized ads offering, which we will begin rolling out this quarter.
However, we continue to monitor legal and regulatory headwinds in the EU and the US that could significantly impact our business and financial results. For example, we continue to see scrutiny on youth-related issues and have a number of trials scheduled for this year in the US, which may ultimately result in a material loss.
In closing, 2025 was another strong year for our company. The investments we've made to improve our business are continuing to drive strong growth, and we have an exciting roadmap this year to deliver new experiences and services for our global community. As always, thank you to our teams for their hard work and commitment to our mission. With that, Krista, let's open up the call for questions.