Claude Sonnet 4.6 vs GPT-5.3 Codex vs GPT-5.2
Too close to call on our weighted score (GPT-5.3 Codex 64, Claude Sonnet 4.6 62, GPT-5.2 61). The right pick depends on what you value most.
AnthropicClaude Sonnet 4.6
62/100- ECI152.3
- Price$3.00 / $15.00
- Context1M
OpenAIGPT-5.3 Codex
64/100- ECI156.8
- Price$1.75 / $14.00
- Context400K
- OpenAI
GPT-5.2
61/100- ECI153.5
- Price$1.75 / $14.00
- Context400K
Too close to call
It is close. Our weighted score puts them within 2 points (GPT-5.3 Codex 64/100, Claude Sonnet 4.6 62/100, GPT-5.2 61/100), so choose by what matters most for your work: GPT-5.3 Codex for raw capability and Claude Sonnet 4.6 for long inputs. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
- CapabilityGPT-5.3 CodexCapabilities Index (ECI): GPT-5.3 Codex 156.8 · GPT-5.2 153.5 · Claude Sonnet 4.6 152.3
- Lowest priceGPT-5.3 Codex and GPT-5.2GPT-5.3 Codex $4.81 · GPT-5.2 $4.81 · Claude Sonnet 4.6 $6.00 per 1M tokens (3:1 blend)
- Longest contextClaude Sonnet 4.6Claude Sonnet 4.6 1,000,000 · GPT-5.3 Codex 400,000 · GPT-5.2 400,000 tokens
- Widest inputsClaude Sonnet 4.6 and GPT-5.3 CodexClaude Sonnet 4.6: Text, Images, PDFs · GPT-5.3 Codex: Text, Images, PDFs · GPT-5.2: Text, Images
- Self-hostingNo open weightsAll three are available only through APIs
| Measure | Weight | Claude Sonnet 4.6 | GPT-5.3 Codex | GPT-5.2 |
|---|---|---|---|---|
| CapabilityCapabilities Index (ECI) | 50% | 81 | 87 | 83 |
| Price | 25% | 13 | 18 | 18 |
| Inputs & features | 15% | 80 | 80 | 70 |
| Context window | 10% | 60 | 44 | 44 |
| Overall | 100% | 62/100 | 64/100 | 61/100 |
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | Claude Sonnet 4.6Anthropic | GPT-5.3 CodexOpenAI | GPT-5.2OpenAI |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 152.3 | 156.8 (best) | 153.5 |
| ECI rank | #40 of 148 | #18 of 148 (best) | #38 of 148 |
| GPQA DiamondGraduate-level science questions | 87.4% | — | 91.4% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | — | — | 67.4% |
| OTIS Mock AIME 2024–2025Competition mathematics | 85.8% | — | 96.1% (best) |
| SWE-bench VerifiedFixing real GitHub issues | 75.2% (best) | 74.8% | 73.8% |
| SimpleQA VerifiedShort factual questions | 35.5% | — | 37.1% (best) |
| Price per million tokens | |||
| Input | $3.00 | $1.75 (best) | $1.75 (best) |
| Output | $15.00 | $14.00 (best) | $14.00 (best) |
| Cached input | $0.30 | $0.175 (best) | $0.175 (best) |
| Blended (3:1) | $6.00 | $4.81 (best) | $4.81 (best) |
| Long-context rate | Same rate | Same rate | Same rate |
| Price source | Official Anthropic API | Official OpenAI API | Official OpenAI API |
| Limits | |||
| Context window | 1,000,000 tokens (best) | 400,000 tokens | 400,000 tokens |
| Max output | 64,000 tokens | 128,000 tokens (best) | 128,000 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | Yes |
| PDFs | Yes | Yes | No |
| Audio | No | No | No |
| Video | No | No | No |
| Reasoning | Yeslow · medium · high · max | Yeslow · medium · high · xhigh | Yeslow · medium · high · xhigh |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | Yes |
| Availability | |||
| Weights | Proprietary | Proprietary | Proprietary |
| API model ID | claude-sonnet-4-6 | gpt-5.3-codex | gpt-5.2 |
| API providers | 41 (best) | 19 | 21 |
| Released | Feb 17, 2026 | Feb 5, 2026 | Dec 11, 2025 |
| Knowledge cutoff | Aug 31, 2025 | Aug 31, 2025 | Aug 31, 2025 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- Claude Sonnet 4.6$60.00
- GPT-5.3 Codex$45.50
- GPT-5.2$45.50
Which should you choose?
Which is better: Claude Sonnet 4.6, GPT-5.3 Codex or GPT-5.2?
It is close. Our weighted score puts them within 2 points (GPT-5.3 Codex 64/100, Claude Sonnet 4.6 62/100, GPT-5.2 61/100), so choose by what matters most for your work: GPT-5.3 Codex for raw capability and Claude Sonnet 4.6 for long inputs. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.
Which is cheaper, Claude Sonnet 4.6, GPT-5.3 Codex or GPT-5.2?
GPT-5.3 Codex is cheaper at $1.75 input / $14.00 output per million tokens (official OpenAI API price). GPT-5.2 costs $1.75 input / $14.00 output per million tokens (official OpenAI API price); Claude Sonnet 4.6 costs $3.00 input / $15.00 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 Codex versus $4.81 for GPT-5.2 (1× as much) and $6.00 for Claude Sonnet 4.6 (1.2× as much).
Which scores higher on benchmarks?
GPT-5.3 Codex scores higher on the Capabilities Index (ECI): GPT-5.3 Codex 156.8 (#18 of 148), GPT-5.2 153.5 (#38 of 148) and Claude Sonnet 4.6 152.3 (#40 of 148). The confidence ranges of the top two overlap (153.5–160.8 vs 151.7–155.4), so treat the gap as small. On individual benchmarks: SWE-bench Verified — Claude Sonnet 4.6 75.2%, GPT-5.3 Codex 74.8%, GPT-5.2 73.8%.
Which is better for coding?
Claude Sonnet 4.6 resolves more real GitHub issues on SWE-bench Verified: Claude Sonnet 4.6 75.2%, GPT-5.3 Codex 74.8% and GPT-5.2 73.8%. All three support tool calling for agent workflows.
Which has the bigger context window?
Claude Sonnet 4.6 has the largest context window at 1,000,000 tokens, against 400,000 for GPT-5.3 Codex and 400,000 for GPT-5.2. Maximum output per response: Claude Sonnet 4.6 up to 64,000, GPT-5.3 Codex up to 128,000, GPT-5.2 up to 128,000 tokens.
Which can read images, PDFs, audio or video?
Claude Sonnet 4.6 accepts text, images and PDFs; GPT-5.3 Codex accepts text, images and PDFs; GPT-5.2 accepts text and images. Claude Sonnet 4.6 handles the widest range of inputs.
Are any of these open source?
No. Claude Sonnet 4.6, GPT-5.3 Codex and GPT-5.2 are proprietary and only available through APIs and apps.
Which is newer?
Claude Sonnet 4.6 is the newest, released Feb 17, 2026. GPT-5.3 Codex came out Feb 5, 2026; GPT-5.2 came out Dec 11, 2025. Knowledge cutoff: Claude Sonnet 4.6 Aug 31, 2025, GPT-5.3 Codex Aug 31, 2025, GPT-5.2 Aug 31, 2025.
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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