GPT-5.3 Chat vs Claude Opus 4.8
Claude Opus 4.8 comes out ahead, 37 to 32 on our weighted score, though GPT-5.3 Chat is 2.1× cheaper per token.
OpenAIGPT-5.3 Chat
32/100- ECI—
- Price$1.75 / $14.00
- Context128K
- Our pick
AnthropicClaude Opus 4.8
37/100- ECI158.3
- Price$5.00 / $25.00
- Context1M
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Claude Opus 4.8 is our pick
Claude Opus 4.8 is the better all-round choice, scoring 37/100 against GPT-5.3 Chat (32). It leads on inputs & features and context window. GPT-5.3 Chat wins on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
- CapabilityNot enough dataNo independent benchmark covers every model here yet
- Lowest priceGPT-5.3 ChatGPT-5.3 Chat $4.81 · Claude Opus 4.8 $10.00 per 1M tokens (3:1 blend)
- Longest contextClaude Opus 4.8Claude Opus 4.8 1,000,000 · GPT-5.3 Chat 128,000 tokens
- Widest inputsClaude Opus 4.8GPT-5.3 Chat: Text, Images · Claude Opus 4.8: Text, Images, PDFs
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | GPT-5.3 Chat | Claude Opus 4.8 |
|---|---|---|---|
| Price | 50% | 18 | 2 |
| Inputs & features | 30% | 60 | 80 |
| Context window | 20% | 24 | 60 |
| Overall | 100% | 32/100 | 37/100 |
Left out because at least one model lacks the data: capability. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GPT-5.3 ChatOpenAI | Claude Opus 4.8Anthropic |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | 158.3 |
| ECI rank | — | #12 of 148 |
| GPQA DiamondGraduate-level science questions | — | 91.0% |
| FrontierMath Tiers 1–3Research-level mathematics | — | 80.0% |
| OTIS Mock AIME 2024–2025Competition mathematics | — | 98.3% |
| SimpleQA VerifiedShort factual questions | — | 53.0% |
| Price per million tokens | ||
| Input | $1.75 (best) | $5.00 |
| Output | $14.00 (best) | $25.00 |
| Cached input | $0.175 (best) | $0.50 |
| Blended (3:1) | $4.81 (best) | $10.00 |
| Long-context rate | Same rate | Same rate |
| Price source | Official OpenAI API | Official Anthropic API |
| Limits | ||
| Context window | 128,000 tokens | 1,000,000 tokens (best) |
| Max output | 16,384 tokens | 128,000 tokens (best) |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | Yes |
| PDFs | No | Yes |
| Audio | No | No |
| Video | No | No |
| Reasoning | No | Yeslow · medium · high · xhigh · max |
| Tool calling | Yes | Yes |
| Structured output | Yes | Yes |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | gpt-5.3-chat-latest | claude-opus-4-8 |
| API providers | 4 | 45 (best) |
| Released | Mar 3, 2026 | May 28, 2026 |
| Knowledge cutoff | Aug 31, 2025 | Jan 2026 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- GPT-5.3 Chat$45.50
- Claude Opus 4.8$100.00
Which should you choose?
Which is better: GPT-5.3 Chat or Claude Opus 4.8?
Claude Opus 4.8 is the better all-round choice, scoring 37/100 against GPT-5.3 Chat (32). It leads on inputs & features and context window. GPT-5.3 Chat wins on price. The score weighs price 50%, inputs & features 30%, context window 20%. None of the shared benchmarks cover every model here yet, so capability is left out of this verdict.
Which is cheaper, GPT-5.3 Chat or Claude Opus 4.8?
GPT-5.3 Chat is cheaper at $1.75 input / $14.00 output per million tokens (official OpenAI API price). Claude Opus 4.8 costs $5.00 input / $25.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $4.81 per million tokens for GPT-5.3 Chat versus $10.00 for Claude Opus 4.8 (2.1× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. GPT-5.3 Chat has not been scored yet and Claude Opus 4.8 has an ECI of 158.3.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-5.3 Chat and Claude Opus 4.8 yet, so there is no like-for-like coding score. Test both on a sample of your own tasks. Both support tool calling for agent workflows.
Which has the bigger context window?
Claude Opus 4.8 has the largest context window at 1,000,000 tokens, against 128,000 for GPT-5.3 Chat. Maximum output per response: GPT-5.3 Chat up to 16,384, Claude Opus 4.8 up to 128,000 tokens.
Which can read images, PDFs, audio or video?
GPT-5.3 Chat accepts text and images; Claude Opus 4.8 accepts text, images and PDFs. Claude Opus 4.8 handles the widest range of inputs.
Are any of these open source?
No. GPT-5.3 Chat and Claude Opus 4.8 are proprietary and only available through APIs and apps.
Which is newer?
Claude Opus 4.8 is the newest, released May 28, 2026. GPT-5.3 Chat came out Mar 3, 2026. Knowledge cutoff: GPT-5.3 Chat Aug 31, 2025, Claude Opus 4.8 Jan 2026.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.
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