GPT-5 vs o3
A complete head-to-head: pricing, context window, benchmarks, modality coverage, and openness, with a programmatic verdict synthesized from the underlying data.
Updated
GPT-5 specs · o3 specs- Priceo3
o3 is roughly 1.3× cheaper on output tokens ($8.00 vs $10.00 per 1M).
- Context windowGPT-5
GPT-5 accepts 400K tokens vs 200K, 2.0× the room for long documents and codebases.
- BenchmarksGPT-5
GPT-5 leads in 2 of 2 shared benchmarks; the biggest gap is on GPQA (graduate-level reasoning), where it scores 89.4 vs 87.7.
- ModalitiesGPT-5
GPT-5 supports 3 modalities (text, vision, audio) vs 2 for o3.
- OpennessTie
Both are closed-weight, API-only.
On balance GPT-5 edges ahead, winning 3 of 5 categories against o3's 1. o3 is roughly 1.3× cheaper on output tokens ($8.00 vs $10.00 per 1M). GPT-5 accepts 400K tokens vs 200K, 2.0× the room for long documents and codebases.
GPT-5 leads in 2 of 2 shared benchmarks; the biggest gap is on GPQA (graduate-level reasoning), where it scores 89.4 vs 87.7. They differ in modality coverage, GPT-5 handles text, vision, audio while o3 handles text, vision, which can be the deciding factor before you even look at benchmarks. Both are closed-weight, API-only.
GPT-5 is the newer of the two, released 4 months after o3, which usually means a more recent knowledge cutoff and updated safety post-training. GPT-5 is usually picked for coding llm and agents workloads, while o3 sees more deployments in reasoning and math. If pricing matters more than every last benchmark point, run the numbers in the calculator below before committing.
Side-by-side specs
| Spec | GPT-5 | o3 |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Released | Aug 2025 | Apr 2025 |
| Modalities | text, vision, audio | text, vision |
| Context window | 400K tokens | 200K tokens |
| Max output | 128K tokens | , |
| Input · 1M | $1.25 / 1M tokens | $2.00 / 1M tokens |
| Output · 1M | $10.00 / 1M tokens | $8.00 / 1M tokens |
| Knowledge cutoff | 2024-09 | 2024-06 |
| Open weights | No | No |
| API available | Yes | Yes |
Pricing at scale
What you'd actually pay at typical workloads. Numbers come from each model's published per-million-token rates.
- Light usage, 100k in / 50k out per day$18.75 vs $18.00
- Heavy usage, 1M in / 500k out per day$188 vs $180
- RAG workload, 5M in / 200k out per day$248 vs $348
Light usage, 100k in / 50k out per day: $18.75 vs $18.00 per month, model B comes out ahead. Heavy usage, 1M in / 500k out per day: $188 vs $180 per month, model B comes out ahead. RAG workload, 5M in / 200k out per day: $248 vs $348 per month, model A comes out ahead.
Estimated spend for the listed models at your usage. Numbers are derived from each model's published per-million-token rates.
- GPT-5$0.625
- o3$0.600
Benchmarks compared
Only sourced numbers. Where a benchmark is missing for one model we show the available value rather than fabricating the other.
- MMLU91.4
- HumanEval96.295.0
- GPQA89.487.7
- SWE-bench Verified74.9
GPT-5 fits when…
- Unified model, reasoning routed automatically per query
- Excellent tool-use and JSON-mode discipline
- Strong agent performance on SWE-bench Verified
- Long-context tasks, handles 400K tokens vs 200K for o3.
- Multimodal needs covering audio.
o3 fits when…
- Industry-leading reasoning depth at launch
- Strong on math, science, and abstract puzzles
- Tool-use during reasoning loops
- Cost-sensitive workloads, 1.3× cheaper than GPT-5 on output tokens.
Consider GPT-5.5
OpenAI's mid-cycle GPT-5 refresh, improved reasoning, tool use, and multimodal grounding over the 2025 launch.
Frequently asked
Is GPT-5 or o3 cheaper?
o3 is cheaper at $8.00 / 1M tokens per million output tokens, vs $10.00 / 1M tokens for GPT-5.Which has the larger context window?
GPT-5 accepts 400K tokens vs 200K for o3.Is GPT-5 or o3 better for coding?
Both GPT-5 and o3 are competitive on coding benchmarks. See each model's individual spec page for HumanEval and SWE-bench scores where published. For an opinionated pick, consult our Best LLM for Coding ranking.Are either of these models open source?
Neither model ships open weights, both are accessible only via their respective providers' APIs.When were GPT-5 and o3 released?
GPT-5 was released by OpenAI on 2025-08-07. o3 was released by OpenAI on 2025-04-16.
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