GPT-5 Nano vs o3
Compare pricing, context windows, and strengths for GPT-5 Nano by OpenAI and o3 by OpenAI - and see how to put either to work in Appaca.
GPT-5 Nano
The fastest and cheapest GPT-5 variant, ideal for summarization, classification, and lightweight tasks requiring high speed and low cost.
View GPT-5 Nanoo3
A powerful reasoning model excelling at complex, multi-step tasks across math, science, coding, and visual reasoning; succeeded by GPT-5.
View o3GPT-5 Nano vs o3 at a glance
Specs and pricing side by side, from the Appaca AI models directory.
| Spec | GPT-5 Nano | o3 |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Model type | Text | Text |
| Context window | 400K tokens | 200K tokens |
| Input price | $0.05 / 1M tokens | $2 / 1M tokens |
| Output price | $0.4 / 1M tokens | $8 / 1M tokens |
| Status | Current | Current |
How GPT-5 Nano and o3 differ
What the numbers mean in practice when choosing between GPT-5 Nano and o3.
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GPT-5 Nano is 98% cheaper on input tokens ($0.05 vs $2 per million), which adds up quickly in document-heavy workloads.
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GPT-5 Nano is 95% cheaper on output tokens ($0.4 vs $8 per million) - the bigger factor for tools that generate long documents.
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GPT-5 Nano's 400K tokens context window is roughly 2x larger than o3's 200K tokens, so it can work across bigger codebases, contracts, or archives in one pass.
Strengths side by side
Where each model shines, according to benchmarks and provider positioning.
GPT-5 Nano
1. Extremely fast performance
- Fastest model in the GPT-5 family.
- Great for real-time workflows, rapid responses, and high-throughput systems.
2. Most cost-efficient GPT-5 model
- Lowest input and output token costs.
- Suitable for large-scale or budget-sensitive applications.
3. Ideal for lightweight, well-scoped tasks
- Excels at summarization, classification, text extraction, and simple logic tasks.
- Best used when tasks are narrow and well-defined.
4. Multimodal input
- Accepts text + image as input.
- Outputs text only.
5. Broad tool support
- Supports Web Search, File Search, Image Generation (as a tool), Code Interpreter, and MCP.
- (Does not support Computer Use.)
o3
1. Advanced reasoning capability
- Designed for multi-step thinking across text, code, and visual inputs.
- Excels at math, science, logic puzzles, and complex analytical workflows.
2. Strong performance across domains
- Highly capable in technical writing, data analysis, and structured problem-solving.
- Useful for research, engineering tasks, and intricate instruction-following.
3. Visual reasoning support
- Accepts image inputs, enabling tasks such as diagram analysis, chart interpretation, and visual logic assessments.
4. High output capacity
- Up to 100,000 output tokens, supporting long-form content, technical breakdowns, and multi-part solutions.
5. Excellent instruction following
- Produces detailed, step-by-step responses for tasks requiring precision and clarity.
- Ideal for educational explanations, system design reasoning, and code walkthroughs.
6. Large 200K context window
- Handles long documents, multi-file reasoning, or extended conversations with minimal loss of context.
7. Broad API support
- Works with Chat Completions, Responses, Realtime, Assistants, Batch, Embeddings, Image Generation, and more.
- Supports streaming and function calling for advanced workflows.
8. Positioned as a legacy reasoning model
- Remains extremely capable but formally succeeded by GPT-5, which offers stronger reasoning and performance.
Use GPT-5 Nano or o3 - or both
Appaca is the AI workspace for operators. Build internal tools and AI co-workers powered by GPT-5 Nano or o3 - connected to your real data and ready for your whole team. No code, no deployment.
Describe it, and it's built
Tell the Appaca agent the internal tool you need and it builds a working app powered by GPT-5 Nano or o3. No code, no API keys, no deployment.
Switch models without rebuilding
Start on GPT-5 Nano, test the same tool on o3, and keep whichever performs better - the rest of your app stays exactly as it is.
Automated for the whole team
Schedule tools to run on autopilot - daily digests, weekly reports, real-time triggers - and share them with your whole team from one workspace.
Describe it, and it's built
Tell the Appaca agent what your team needs and it builds a working app powered by GPT-5 Nano or o3 - connected to the tools you already use.
Related comparisons
See how GPT-5 Nano and o3 stack up against other models in the directory.
FAQs
GPT-5 Nano is generally cheaper: $0.05 input / $0.4 output per million tokens, versus $2 / $8 for o3. Actual cost depends on how many tokens your workload reads and writes.
GPT-5 Nano has the larger context window at 400K tokens, compared to 200K tokens for o3. A larger window means the model can consider more text at once - useful for long contracts, codebases, or months of records.
It depends on the job. Compare the pricing, context window, and strengths above against your workload - and remember the choice isn't permanent. In Appaca you can build a tool on GPT-5 Nano, test the same tool on o3, and switch at any time without rebuilding anything.
Yes. Appaca is a no-code AI workspace: describe the internal tool your team needs and the Appaca agent builds it as a working app powered by GPT-5 Nano, o3, or any other model in the directory - with a built-in database, team access, and integrations. No API keys to wire up and nothing to deploy.
Build AI tools with GPT-5 Nano or o3
Describe the tool your team needs and get a working app powered by the model you choose - with a built-in database, team access, and integrations. No code, no deployment.