GPT-5 vs o3
Detailed pricing comparison and cost analysis.
Updated March 2026
Cost Simulator
| Feature | GPT-5 | o3 |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Input Price (1M) | $1.25 | $2.00 |
| Output Price (1M) | $10.00 | $8.00 |
| Context Window | 400,000 | 200,000 |
Verdict
GPT-5 costs $1.25 per 1M input tokens and $10.00 per 1M output tokens. o3 costs $2.00 per 1M input tokens and $8.00 per 1M output tokens. GPT-5 is 38% cheaper on input tokens than o3. For output tokens, o3 is the more affordable option at $8.00/1M vs $10.00.
On context window, GPT-5 supports 400,000 tokens — meaning it can fit more conversation history, documents, or code in a single request. This matters for RAG pipelines, long document analysis, and agentic workflows where context builds up over many turns.
When to choose GPT-5
- ✓ You need the lowest input token cost ($ 1.25/1M)
- ✓ You need a larger context window (400,000 tokens)
- ✓ You are already integrated with OpenAI
When to choose o3
- ✓ Your workload is output-heavy — o3 generates text cheaper
- ✓ You are already integrated with OpenAI
Use the calculator above to simulate your specific workload and find the exact break-even point. For most applications, the cheapest model is the one that minimises your total monthly bill given your input-to-output token ratio.