Business Context and Reporting Period
Company: Duolingo, Inc.
Filing Type: Form 10-K (Annual Report)
Reporting Period: Fiscal year ended December 31, 2025
Business Overview: Duolingo operates a freemium mobile learning platform offering language, math, music, and chess courses, alongside the Duolingo English Test. The company utilizes a "learning flywheel" driven by user data and AI to improve engagement and efficacy. As of December 31, 2025, the platform served over 130 million monthly active users (MAUs) globally.
Key Financial Metrics
| Metric | 2025 | 2024 | Change |
|---|---|---|---|
| Total Revenue | $1,037.6 million | $748.0 million | +39% |
| Subscription Revenue | $873.4 million | $607.5 million | +44% |
| Other Revenue (Ads, Test, IAPs) | $164.1 million | $140.5 million | +17% |
| Gross Profit | $749.5 million | $544.4 million | +38% |
| Gross Margin | 72.2% | 72.8% | -0.6 pts |
| Operating Income | $135.6 million | $62.6 million | +117% |
| Net Income (GAAP) | $414.1 million | $88.6 million | +367% |
| Adjusted EBITDA | $305.9 million | $191.9 million | +59% |
| Free Cash Flow | $360.4 million | $264.4 million | +36% |
| Cash & Equivalents (End of Period) | $1,036.4 million | $785.8 million | N/A |
Note: Net Income for 2025 includes a one-time income tax benefit of $256.7 million from the release of a valuation allowance on deferred tax assets.
Material Changes vs. Prior Period
- Revenue Growth: Driven primarily by a 44% increase in subscription revenue due to higher paid subscriber counts (12.2 million in 2025 vs. 9.5 million in 2024) and increased advertising revenue from higher Daily Active Users (DAUs).
- Operating Expenses: Increased 27% to $613.9 million. Research and Development (R&D) rose 30% due to headcount growth and increased GenAI costs ($3.6 million increase). Sales and Marketing rose 39% due to higher direct marketing spend.
- Profitability: Operating margin improved from 8% to 13%. The significant jump in Net Income was largely non-recurring, driven by the tax benefit mentioned above.
- User Metrics: MAUs grew 14% to 133.1 million; DAUs grew 30% to 52.7 million. The DAU/MAU engagement ratio improved to 39.6% from 34.7%.
- Acquisitions: Completed the acquisition of NextBeat (Music Learning Services) in July 2025 for $34.5 million and Hobbes in July 2024.
Guidance, Outlook, Risks, and Unusual Items
- Unusual Items: The 2025 effective tax rate was -127% due to the release of a $256.7 million valuation allowance on deferred tax assets, a non-recurring event. Management does not expect this rate to be indicative of future periods.
- Outlook & Strategy: Management continues to invest heavily in AI (e.g., Duolingo Max, Video Call) and new subjects (Chess, Math, Music). The company expects costs to continue growing as it scales infrastructure and headcount.
- Capital Allocation: In February 2026 (subsequent event), the Board authorized a $400 million share repurchase program.
- Key Risks:
- Platform Dependency: 62% of revenue and 61% of bookings in 2025 were derived from the Apple App Store; 20% from Google Play Store. Changes in their terms or fees could materially impact the business.
- AI & Regulatory: Reliance on third-party AI models and evolving regulations (EU AI Act, US state laws) regarding AI and data privacy pose compliance and operational risks.
- Competition: Low switching costs in the language learning market and potential disruption from new entrants using generative AI.
- Infrastructure: Reliance on AWS and Google Cloud; a 12-hour outage occurred in October 2025 due to an AWS regional failure.
Investor Verification Checklist
- Tax Normalization: Verify the sustainability of profitability by excluding the $256.7 million one-time tax benefit from 2025 Net Income analysis.
- AI Cost Trajectory: Monitor the impact of increasing GenAI costs on Gross Margin, which declined slightly to 72.2% in 2025.
- Platform Concentration: Assess the risk exposure to Apple and Google, which collectively processed over 85% of revenue.
- Subscriber Retention: Review future quarters for paid subscriber retention rates as the user base matures and marketing spend increases.
- Share Repurchase Execution: Track the utilization of the newly authorized $400 million buyback program and its impact on diluted share count.