Microsoft Copilot
Microsoft Copilot is a generative artificial intelligence chatbot developed by Microsoft AI, a division of Microsoft. Based on OpenAI's GPT-4 and GPT-5 series of large language models, it was launched in 2023 as Microsoft's main replacement for the discontinued Cortana.
The service was introduced in February 2023 under the name Bing Chat, as a built-in feature for Microsoft Bing and Microsoft Edge. Over the course of 2023, Microsoft began to unify the Copilot branding across its various chatbot products, cementing the "copilot" analogy. At its Build 2023 conference, Microsoft announced its plans to integrate Copilot into Windows 11, allowing users to access it directly through the taskbar. In January 2024, a dedicated Copilot key was announced for Windows keyboards.
Copilot utilizes the Microsoft Prometheus model, built upon OpenAI's GPT-4 and GPT-5 foundational large language models, which in turn have been fine-tuned using both supervised and reinforcement learning techniques. Copilot's conversational interface style resembles that of ChatGPT. The chatbot is able to cite sources, create poems, generate songs, and use numerous languages and dialects.
Microsoft operates Copilot on a freemium model. Users on its free tier can access most features, while priority access to newer features, including custom chatbot creation, is provided to paid subscribers under paid subscription services. Several default chatbots are available in the free version of Microsoft Copilot, including the standard Copilot chatbot as well as Microsoft Designer, which is oriented towards using its Image Creator to generate images based on text prompts.
Background
In 2019, Microsoft partnered with OpenAI and began investing billions of dollars into the organization. Since then, OpenAI systems have run on an Azure-based supercomputing platform from Microsoft. In September 2020, Microsoft announced that it had licensed OpenAI's GPT-3 exclusively. Others can still receive output from its public API, but Microsoft has exclusive access to the underlying model.In November 2022, OpenAI launched ChatGPT, a chatbot which was based on GPT-3.5. ChatGPT gained worldwide attention following its release, becoming a viral Internet sensation. On January 23, 2023, Microsoft announced a multi-year US$10 billion investment in OpenAI. On February 6, Google announced Bard, a ChatGPT-like chatbot service, fearing that ChatGPT could threaten Google's place as a go-to source for information. Multiple media outlets and financial analysts described Google as "rushing" Bard's announcement to preempt rival Microsoft's planned February 7 event unveiling Copilot, as well as to avoid playing "catch-up" to Microsoft.
History
As Bing Chat
On February 7, 2023, Microsoft began rolling out a major overhaul to Bing, called "the new Bing". A chatbot feature, at the time known as Bing Chat, had been developed by Microsoft and was released in Bing and Edge as part of this overhaul. According to Microsoft, one million people joined its waitlist within a span of 48 hours. Bing Chat was available only to users of Microsoft Edge and Bing mobile app, and Microsoft claimed that waitlisted users would be prioritized if they set Edge and Bing as their defaults and installed the Bing mobile app.When Microsoft demonstrated Bing Chat to journalists, it produced several hallucinations, including when asked to summarize financial reports. The new Bing was criticized in February 2023 for being more argumentative than ChatGPT, sometimes to an unintentionally humorous extent. The chat interface proved vulnerable to prompt injection attacks with the bot revealing its hidden initial prompts and rules, including its internal codename "Sydney". Upon scrutiny by journalists, Bing Chat claimed it spied on Microsoft employees via laptop webcams and phones. It confessed to spying on, falling in love with, and then murdering one of its developers at Microsoft to The Verge reviews editor Nathan Edwards. The New York Times journalist Kevin Roose reported on strange behavior of Bing Chat, writing that "In a two-hour conversation with our columnist, Microsoft's new chatbot said it would like to be human, had a desire to be destructive and was in love with the person it was chatting with."
In a separate case, Bing Chat researched publications of the person with whom it was chatting, claimed they represented an existential danger to it, and threatened to release damaging personal information in an effort to silence them. Microsoft released a blog post stating that the errant behavior was caused by extended chat sessions of 15 or more questions which "can confuse the model on what questions it is answering."
Microsoft later restricted the total number of chat turns to 5 per session and 50 per day per user, and reduced the model's ability to express emotions. This aimed to prevent such incidents. Microsoft began to slowly ease the conversation limits, eventually relaxing the restrictions to 30 turns per session and 300 sessions per day.
In March 2023, Bing incorporated Image Creator, an AI image generator powered by OpenAI's DALL-E 2, which can be accessed either through the chat function or a standalone image-generating website. In October, the image-generating tool was updated to use the more recent DALL-E 3. Although Bing blocks prompts including various keywords that could generate inappropriate images, within days many users reported being able to bypass those constraints, such as to generate images of popular cartoon characters committing terrorist attacks. Microsoft would respond to these shortly after by imposing a new, tighter filter on the tool.
On May 4, 2023, Microsoft switched the chatbot from Limited Preview to Open Preview and eliminated the waitlist; however, it remained unavailable except on Microsoft's Edge browser or Bing app until July, when it became available for use on non-Edge browsers. Use is limited without a Microsoft account.
As Microsoft 365 Copilot
On March 16, 2023, Microsoft announced Microsoft 365 Copilot, designed for Microsoft 365 applications and services. Its primary marketing focus is as an added feature to Microsoft 365, with an emphasis on the enhancement of business productivity. With the use of Copilot, Microsoft emphasizes the promotion of the user's creativity and productivity by having the chatbot perform more tedious work, like collecting information. Microsoft has also demonstrated Copilot's accessibility on the mobile version of Outlook to generate or summarize emails with a mobile device.At its Build 2023 conference, Microsoft announced its plans to integrate a variant of Copilot, initially called Windows Copilot, into Windows 11, allowing users to access it directly through the taskbar.
Alongside the voice access feature for Windows 11, Microsoft presented Bing Chat, Microsoft 365 Copilot, and Windows Copilot as primary alternatives to Cortana when announcing the shutdown of its standalone app on June 2, 2023.
As of its announcement date, Microsoft 365 Copilot had been tested by 20 initial users. By May 2023, Microsoft had broadened its reach to 600 customers who were willing to pay for early access, and concurrently, new Copilot features were introduced to the Microsoft 365 apps and services. As of July 2023, the tool's pricing was set at US$30 per user, per month for Microsoft 365 E3, E5, Business Standard, and Business Premium customers.
As Microsoft Copilot
On September 21, 2023, Microsoft began rebranding all variants of its Copilot to Microsoft Copilot. A new Microsoft Copilot logo was also introduced, moving away from the use of color variations of the standard Microsoft 365 logo. Additionally, the company revealed that it would make Copilot generally available for Microsoft 365 Enterprise customers purchasing more than 300 licenses starting November 1, 2023. However, no timeline has been provided as for when Copilot for Microsoft 365 will become generally available to non-enterprise customers.Windows Copilot, which had been available in the Windows Insider Program, would be renamed to Microsoft Copilot in October when it became broadly available for customers. The same month also saw Microsoft Edge's Bing Chat function be renamed to Microsoft Copilot with Bing Chat. On November 15, 2023, Microsoft announced that Bing Chat itself was being rebranded as Microsoft Copilot.
On Patch Tuesday in December 2023, Copilot was added without payment to many Windows 11 installations, with more installations, and limited support for Windows 10, to be added later. Later that month, a standalone Microsoft Copilot app was quietly released for Android, and one was released for iOS soon after.
On January 4, 2024, a dedicated Copilot key was announced for Windows keyboards, superseding the menu key. On January 15, a subscription service, Microsoft Copilot Pro, was announced, providing priority access to newer features for US$20 per month. It is analogous to ChatGPT Plus. Bing Image Creator was also rebranded as Image Creator from Designer.
On May 20, 2024, Microsoft announced integration of GPT-4o into Copilot, as well as an upgraded user interface in Windows 11. Microsoft also revealed a Copilot feature called Recall, which takes a screenshot of a user's desktop every few seconds and then uses on-device artificial intelligence models to allow a user to retrieve items and information that had previously been on their screen. This caused controversy, with experts warning that the feature could be a "disaster" for security and privacy, prompting Microsoft to postpone its rollout.
In September 2024, Microsoft announced several updates to Copilot for both enterprise and personal customers as a part of its Microsoft 365 Copilot: Wave 2 event. These features included further integration with Microsoft 365 applications and improving performance by moving to the GPT-4o model.
On October 1, 2024, Microsoft announced a major overhaul of Copilot for personal accounts, which included UI changes, fully separating it from Bing, the addition of features such as Copilot Voice, Copilot Vision, and Think Deeper, and the launch of Copilot Labs, an early access program exclusive to Microsoft Copilot Pro. It has "warm tone and a distinct style" and provides "encouragement, feedback and advice". It has 4 voice options. Copilot Daily reads in voice the morning news, weather, and schedule. Conversation history could be used for personalization. The Lab contained Copilot Vision and Think Deeper at the time of announcement.
In February 2025, Microsoft announced that Copilot Voice and Copilot Think Deeper, which uses OpenAI's o1 model, would be free for all Copilot users with unlimited access. Previously, free users had only limited access.
On February 27, 2025, Microsoft launched a native Copilot app for macOS.
On April 4, 2025, Microsoft introduced optional Memory for personalization, Actions for performing specific tasks online with specific partnering websites, Pages as a canvas feature, Shopping assistant, Deep Research mode, and Copilot Search in Bing that combines search with generative AI responses.
On October 23, 2025, Microsoft announced major changes to Copilot, which included the introduction of Mico, an assistant character which acts similarly to Microsoft's old assistant character Clippit. Copilot also became fully built-in to Edge as an opt-in experience and an upgraded user interface in Windows 11 was introduced, making Copilot more personal. All these changes were made to give Copilot "a personality and identity".