GPT-6 Sol vs GPT-5.3 Codex
GPT-6 Sol comes out ahead, 47 to 42 on our weighted score, and it is the cheaper option too.
- Our pick
OpenAIGPT-6 Sol
47/100- ECI—
- Price$2.00 / $10.00
- Context1.05M
- OpenAI
GPT-5.3 Codex
42/100- ECI156.8
- Price$1.75 / $14.00
- Context400K
Add a model
Make it a three-way comparison.
GPT-6 Sol is our pick
GPT-6 Sol is the better all-round choice, scoring 47/100 against GPT-5.3 Codex (42). It leads on price and context window. 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-6 SolGPT-6 Sol $4.00 · GPT-5.3 Codex $4.81 per 1M tokens (3:1 blend)
- Longest contextGPT-6 SolGPT-6 Sol 1,050,000 · GPT-5.3 Codex 400,000 tokens
- Widest inputsSame inputsGPT-6 Sol: Text, Images, PDFs · GPT-5.3 Codex: Text, Images, PDFs
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | GPT-6 Sol | GPT-5.3 Codex |
|---|---|---|---|
| Price | 50% | 21 | 18 |
| Inputs & features | 30% | 80 | 80 |
| Context window | 20% | 61 | 44 |
| Overall | 100% | 47/100 | 42/100 |
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-6 SolOpenAI | GPT-5.3 CodexOpenAI |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | — | 156.8 |
| ECI rank | — | #18 of 148 |
| GPQA DiamondGraduate-level science questions | 94.3% | — |
| FrontierMath Tiers 1–3Research-level mathematics | 89.8% | — |
| OTIS Mock AIME 2024–2025Competition mathematics | 100% | — |
| SWE-bench VerifiedFixing real GitHub issues | — | 74.8% |
| SimpleQA VerifiedShort factual questions | 60.7% | — |
| Price per million tokens | ||
| Input | $2.00 | $1.75 (best) |
| Output | $10.00 (best) | $14.00 |
| Cached input | $0.20 | $0.175 (best) |
| Blended (3:1) | $4.00 (best) | $4.81 |
| Long-context rate | Over 272K: $4.00 / $15.00 | Same rate |
| Price source | Official OpenAI API | Official OpenAI API |
| Limits | ||
| Context window | 1,050,000 tokens (best) | 400,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | Yes |
| PDFs | Yes | Yes |
| Audio | No | No |
| Video | No | No |
| Reasoning | Yeslow · medium · high · xhigh · max | Yeslow · medium · high · xhigh |
| Tool calling | Yes | Yes |
| Structured output | Yes | Yes |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | gpt-6-sol | gpt-5.3-codex |
| API providers | 25 (best) | 19 |
| Released | Sep 22, 2026 | Feb 5, 2026 |
| Knowledge cutoff | Apr 20, 2026 | 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.
- GPT-6 Sol$40.00
- GPT-5.3 Codex$45.50
Which should you choose?
Which is better: GPT-6 Sol or GPT-5.3 Codex?
GPT-6 Sol is the better all-round choice, scoring 47/100 against GPT-5.3 Codex (42). It leads on price and context window. 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-6 Sol or GPT-5.3 Codex?
GPT-6 Sol is cheaper at $2.00 input / $10.00 output per million tokens (official OpenAI API price). GPT-5.3 Codex costs $1.75 input / $14.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $4.00 per million tokens for GPT-6 Sol versus $4.81 for GPT-5.3 Codex (1.2× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. GPT-6 Sol has not been scored yet and GPT-5.3 Codex has an ECI of 156.8.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-6 Sol 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?
GPT-6 Sol has the largest context window at 1,050,000 tokens, against 400,000 for GPT-5.3 Codex. Maximum output per response: GPT-6 Sol up to 128,000, GPT-5.3 Codex up to 128,000 tokens.
Which can read images, PDFs, audio or video?
GPT-6 Sol accepts text, images and PDFs; GPT-5.3 Codex accepts text, images and PDFs. They handle the same number of input types.
Are any of these open source?
No. GPT-6 Sol and GPT-5.3 Codex are proprietary and only available through APIs and apps.
Which is newer?
GPT-6 Sol is the newest, released Sep 22, 2026. GPT-5.3 Codex came out Feb 5, 2026. Knowledge cutoff: GPT-6 Sol Apr 20, 2026, GPT-5.3 Codex 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.
Related comparisons
- Add Claude Sonnet 5.5Three-way comparison
- GPT-6 Sol vs Claude Sonnet 5.5Anthropic · ECI 165.2
- GPT-6 Sol vs Grok 4.6xAI · ECI 156.6
- GPT-6 Sol vs Gemini 3.1 Pro PreviewGoogle · ECI 154.8
- GPT-6 Sol vs Qwen3.8 MaxAlibaba (Qwen) · ECI 156.6
- GPT-5.3 Codex vs Gemini 3.1 Pro PreviewGoogle · ECI 154.8
- GPT-5.3 Codex vs Claude Sonnet 5Anthropic · ECI 156.3
