Leaderboard · Compare · o3 vs GPT-5 · Updated
o3 vs GPT-5
GPT-5 edges out o3 on the composite (86.0 vs 83.7). The gap is meaningful but not decisive — see the per-benchmark breakdown below.
At a glance
| Spec | o3 | GPT-5 |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Released | 2025-04 | 2025-08 |
| Tier | frontier | frontier |
| License | Closed | Closed |
| Context window | 200k | 400k |
| $ in / out (per 1M) | $2.00 / $8.00 | $1.25 / $10.00 |
Benchmark scoreboard
Higher is better on every benchmark. Δ shows o3 − GPT-5.
| Benchmark | o3 | GPT-5 | Δ |
|---|---|---|---|
| Chatbot Arena Elo | 1380 | 1410 | -30 |
| MMLU-Pro | 85.7 | 86.8 | -1.1 |
| GPQA Diamond | 87.7 | 87.3 | +0.4 |
| MATH | 96.7 | 96.7 | +0.0 |
| HumanEval | 92.7 | 95.1 | -2.4 |
| SWE-Bench Verified | 71.7 | 74.9 | -3.2 |
Numbers compiled from provider technical reports and Chatbot Arena snapshots — see methodology.
OpenRouter routes o3, GPT-5, and 100+ other LLMs behind a single API key — pay-as-you-go, no monthly minimum, fallback if a provider is down. Try OpenRouter → (affiliate · supports this site)
o3 vs GPT-5: where each one wins
o3 is stronger on
- GPQA
GPT-5 is stronger on
- Arena
- MMLU-Pro
- HumanEval
- SWE-Bench
Cost comparison
At 10M tokens/day (50/50 split), o3 costs ~$50.00/day vs $56.25/day for GPT-5 — o3 is the cheaper pick at this volume.
Verdict
GPT-5 edges out o3 on the composite (86.0 vs 83.7). The gap is meaningful but not decisive — see the per-benchmark breakdown below.
If you can only pick one and your workload is unclear, route via OpenRouter and switch by request — same key, no lock-in.
Frequently asked questions
Which is better, o3 or GPT-5?
GPT-5 edges out o3 on the composite (86.0 vs 83.7). The gap is meaningful but not decisive — see the per-benchmark breakdown below. o3 wins on GPQA; GPT-5 wins on Arena, MMLU-Pro, HumanEval, SWE-Bench.
What does o3 cost compared to GPT-5?
At 10M tokens/day (50/50 split), o3 costs ~$50.00/day vs $56.25/day for GPT-5 — o3 is the cheaper pick at this volume.
What is the context window of o3 vs GPT-5?
o3: 200k tokens. GPT-5: 400k tokens. GPT-5 has the larger window — useful for long-document RAG and full-codebase prompting.
Is o3 or GPT-5 open source?
o3: closed / proprietary. GPT-5: closed / proprietary.
Can I try o3 and GPT-5 on the same API key?
Yes — OpenRouter routes both models behind a single key, so you can A/B test o3 against GPT-5 without juggling provider accounts.
Model deep-dives: o3 · GPT-5 · Full leaderboard
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