OpenAI

o3legacy

Chain-of-thought reasoning model, a former math and code benchmark leader.

#496released Apr 15, 2025·Proprietary·Not disclosed
textimage200K ctxreasoning
API providersGet API Key →Leaderboard
Intelligence
32.0 #496
Top 65% tier
Output Speed
90 t/s
ITL 11.1 ms/tok
Blended price (3:1)
$4.375 /1M
In $2.5/M · Out $10/M
Context
200K
≈ 500 A4 pages · max out 16,384

Quality Domain Radar

6-Axis Frontier Evaluation vs Category Average & Flagship

o3
Claude Mythos Preview (#1)
Average (68)
Coding (35)Mathematics (37)Hard Science (GPQA) (38)Agentic & Tool Use (30)Knowledge (MMLU) (32)Vision / Multimodal (51.6)

Radar axes are approximated from category scores where direct benchmark measurements are missing — see Methodology.

Strengths & Trade-offs

Where it wins

  • Cheap prompt-cache reads at $0.25/1M
  • Reasoning mode with adjustable effort levels

Trade-offs to watch

  • Legacy tier — a newer successor is available
  • Architecture and weights undisclosed — API access only

Killer Use Cases

Whole-repo analysis
Single-pass ingestion of large codebases, contracts or research corpora.
Vision & document OCR
Extracts structure from scans, charts, screenshots and mixed-media inputs.

Developer Quickstart & API

Set OPENAI_API_KEY first — get an API key
curl https://api.openai.com/v1/responses \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "content-type: application/json" \
  -d '{
    "model": "o3",
    "input": "Refactor this function for O(n) time and explain the change."
  }'

Official Resources & Links

API deployment

Compare hosts & latency

Throughput, TTFT and cache pricing across Groq, Cerebras, Together, DeepInfra, Fireworks, Bedrock and Azure.

GroqCerebrasTogether AIDeepInfraFireworks AIAWS BedrockAzure AI
View providers matrix →

Scores by Source

Live Specs & Architecture

Under the hood
  • Switchable reasoning effort — trading latency and tokens for accuracy on hard problems.
  • Prompt caching supported — cached input reads at $0.25/1M tokens.
Release date
Apr 15, 2025
Parameters
Not disclosed
License
Proprietary
Context Window
200,000 tokens
Max Output
16,384 tokens
Modalities
text + image
Cache Pricing
read $0.25 · write $3.125 /1M
Reasoning
Effort levels
Input Price
$2.5/M
Output Price
$10/M
Output Speed
90 t/s
Time to First Token
—
Data Updated
Aug 5, 2026

Estimated monthly bill

Estimated monthly spend
$0.00
Calculating savings vs GPT-4o...

Cite & embed

GitHub Markdown badge
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BibTeX
@misc{llmpodium2026o3,
  title = {Benchmark Analysis and Intelligence Evaluation of o3},
  author = {LLMPodium Research},
  year = {2026},
  url = {https://llmpodium.com/models/o3}
}

Embed Score Badge

Add a live Podium Score badge to your GitHub or Hugging Face README — it links back to the live ranking.

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o3 LLMPodium Score
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