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OpenAI o3: Powerful, Well-Rounded Reasoning
Released on April 16, 2025 as part of the OpenAI o-series lineup, OpenAI o3 sits alongside OpenAI-o4-mini and GPT-4.1, positioned as a robust, domain-flexible reasoning model and the predecessor to GPT-5.
Designed for technical writing and reliable instruction-following, it provides strong, well-rounded performance across complex tasks in varied domains. These capabilities make it an excellent fit for creating technical documents, generating step-by-step explanations, and supporting workflows that demand clear, structured reasoning.
OpenAI o3: Key Specs
Below are OpenAI o3's main specs and how they translate into real-world behavior.
- Context Window - Up to 200,000 tokens: This wide context capacity helps OpenAI o3 keep track of long conversations or large documents, allowing it to follow extended, multi-step instructions without losing earlier details.
- Maximum Output Length - Up to 100,000 tokens: The model can generate long, continuous responses, making it suitable for detailed explanations, complex write-ups, or multi-section content created in one pass.
- Speed and Efficiency - Slower, more deliberate performance: OpenAI o3 responds at a measured pace, making it well-suited for tasks that benefit from deeper reasoning and careful processing rather than raw speed.
- Cost Efficiency - Positioned at a moderate-to-high price tier: The model's cost reflects its stronger capabilities, making it a practical choice for higher-value workloads that benefit from enhanced reasoning.
- Reasoning and Accuracy - Highest-level reasoning ability: OpenAI o3 excels at complex logic, structured analysis, and demanding problem-solving, delivering precise and reliable results for challenging tasks.
- Multimodal Capabilities - Supports text and image input, outputs text: It can interpret visual material alongside written prompts, enabling workflows that involve screenshots, diagrams, or mixed-content analysis.
Compare OpenAI o3, OpenAI o4-mini, and OpenAI o1
A brief overview of how each model differs in power, speed, and use cases.
| Feature | OpenAI o3 | OpenAI o4-mini | OpenAI o1 |
|---|---|---|---|
| Knowledge Cutoff | Jun 01, 2024 | Jun 01, 2024 | Oct 01, 2023 |
| Context Window (Tokens) | 200,000 | 200,000 | 200,000 |
| Max Output Tokens | 100,000 | 100,000 | 100,000 |
| Input Modalities | Text, image | Text, image | Text, image |
| Output Modalities | Text | Text | Text |
| Latency (OpenRouter Data) | 5.51s | 4.28s | 26.49s |
| Speed | Slowest in OpenAI o3 series | Medium (still faster than OpenAI o3) | Slowest in OpenAI o-series |
| Input / Output Cost per 1M Tokens | $2 / $8 | $1.1 / $4.4 | $15 / $60 |
| Reasoning Performance | Highest | Very High | Very High |
| Coding Performance (on SWE-bench Verified) | 69.10% | 68.10% | 48.90% |
| Best For | technical writing and instruction-following | STEM tasks, visual problem solving and code editing | math, science, programming, and other STEM-related tasks |
Source: OpenAI o3 Documentation
Best Cases to Use OpenAI o3
OpenAI o3 is best for delivering clear structure and dependable step-by-step guidance.
- For students and learners: Use OpenAI o3 to understand detailed explanations, follow structured reasoning, and break down complex subjects into clear steps that support deeper learning and comprehension.
- For developers: Generate technical documentation, walk through multi-step coding instructions, and clarify implementation details with consistent, accurate explanations tailored to structured workflows.
- For businesses and teams: Produce polished reports, procedural guides, and reliable written instructions that improve clarity and consistency across internal documentation and communications.
- For product teams and app builders: Create features that rely on precise instruction-following, enabling tools and agents that perform structured tasks with predictable, repeatable accuracy.
- For operations and support workflows: Develop step-by-step troubleshooting guides, document processes clearly, and ensure consistent execution of operational tasks through reliable written instructions.
- For content and marketing helpers: Turn complex technical ideas into clear, comprehensible content that maintains accuracy while improving readability for broader audiences.
How to Access OpenAI o3
Accessing OpenAI o3 is easy, and you can select the approach that aligns with your needs.
1. OpenAI API
OpenAI o3 is accessible through the official OpenAI API. This requires an API key and billing plan, making it ideal for developers who want full integration control within apps or custom systems.
2. EssayDone AI Chat
For fast, hassle-free access, OpenAI o3 is available in EssayDone AI Chat.
It provides identical model output with zero setup, perfect for students, writers, and professionals who want immediate, user-friendly access.
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FAQ
Here are some frequently asked questions about OpenAI o3.
Yes. OpenAI o3 provides the highest level of reasoning ability in its series, with performance aligned to a top-tier rating of 5. It excels at complex analysis, structured logic, and detailed instruction-following tasks.
OpenAI o3 costs $2 per 1M input tokens and $8 per 1M output tokens. It is priced as a high-capability model within the OpenAI o-series.
OpenAI o3 is optimized for technical writing, detailed instruction-following, and tasks that require precise reasoning. It performs especially well in structured, knowledge-heavy workflows where clarity and accuracy matter.
OpenAI o3 accepts text and image inputs and produces text outputs. It can interpret images at a functional level, but its multimodal capability is more limited than models designed for advanced visual reasoning.
OpenAI o3 offers stronger reasoning, higher accuracy, and image-input support, making it more capable than OpenAI o3-mini. The Mini version is faster and more affordable, but OpenAI o3 is the better choice for complex writing and instruction-heavy tasks.
Using OpenAI o3 in EssayDone AI Chat requires no API key, has no daily message limits, and comes with no geographical restrictions. You can access ChatGPT and many other AI models on one platform with a single payment, at a more affordable price.