GPT-5.5 vs GPT-5.3 Chat
GPT-5.5 comes out ahead, 36 to 32 on our weighted score, though GPT-5.3 Chat is 2.3× cheaper per token.
- Our pick
OpenAIGPT-5.5
36/100- ECI159.2
- Price$5.00 / $30.00
- Context1.05M
- OpenAI
GPT-5.3 Chat
32/100- ECI—
- Price$1.75 / $14.00
- Context128K
Add a model
Make it a three-way comparison.
GPT-5.5 is our pick
GPT-5.5 is the better all-round choice, scoring 36/100 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 · GPT-5.5 $11.25 per 1M tokens (3:1 blend)
- Longest contextGPT-5.5GPT-5.5 1,050,000 · GPT-5.3 Chat 128,000 tokens
- Widest inputsGPT-5.5GPT-5.5: Text, Images, PDFs · GPT-5.3 Chat: Text, Images
- Self-hostingNo open weightsBoth are available only through APIs
| Measure | Weight | GPT-5.5 | GPT-5.3 Chat |
|---|---|---|---|
| Price | 50% | 0 | 18 |
| Inputs & features | 30% | 80 | 60 |
| Context window | 20% | 61 | 24 |
| Overall | 100% | 36/100 | 32/100 |
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-5.5OpenAI | GPT-5.3 ChatOpenAI |
|---|---|---|
| Capability | ||
| Capabilities Index (ECI) | 159.2 | — |
| ECI rank | #10 of 148 | — |
| GPQA DiamondGraduate-level science questions | 94.0% | — |
| FrontierMath Tiers 1–3Research-level mathematics | 85.3% | — |
| OTIS Mock AIME 2024–2025Competition mathematics | 100% | — |
| SWE-bench VerifiedFixing real GitHub issues | 80.6% | — |
| SimpleQA VerifiedShort factual questions | 63.0% | — |
| Price per million tokens | ||
| Input | $5.00 | $1.75 (best) |
| Output | $30.00 | $14.00 (best) |
| Cached input | $0.50 | $0.175 (best) |
| Blended (3:1) | $11.25 | $4.81 (best) |
| Long-context rate | Over 272K: $10.00 / $45.00 | Same rate |
| Price source | Official OpenAI API | Official OpenAI API |
| Limits | ||
| Context window | 1,050,000 tokens (best) | 128,000 tokens |
| Max output | 128,000 tokens (best) | 16,384 tokens |
| Inputs and features | ||
| Text | Yes | Yes |
| Images | Yes | Yes |
| PDFs | Yes | No |
| Audio | No | No |
| Video | No | No |
| Reasoning | Yeslow · medium · high · xhigh | No |
| Tool calling | Yes | Yes |
| Structured output | Yes | Yes |
| Availability | ||
| Weights | Proprietary | Proprietary |
| API model ID | gpt-5.5 | gpt-5.3-chat-latest |
| API providers | 42 (best) | 4 |
| Released | Apr 23, 2026 | Mar 3, 2026 |
| Knowledge cutoff | Dec 1, 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.
- GPT-5.5$110.00
- GPT-5.3 Chat$45.50
Which should you choose?
Which is better: GPT-5.5 or GPT-5.3 Chat?
GPT-5.5 is the better all-round choice, scoring 36/100 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-5.5 or GPT-5.3 Chat?
GPT-5.3 Chat is cheaper at $1.75 input / $14.00 output per million tokens (official OpenAI API price). GPT-5.5 costs $5.00 input / $30.00 output per million tokens (official OpenAI 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 $11.25 for GPT-5.5 (2.3× as much).
Which scores higher on benchmarks?
There is no independent benchmark that covers both models yet. GPT-5.5 has an ECI of 159.2 and GPT-5.3 Chat has not been scored yet.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-5.3 Chat 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-5.5 has the largest context window at 1,050,000 tokens, against 128,000 for GPT-5.3 Chat. Maximum output per response: GPT-5.5 up to 128,000, GPT-5.3 Chat up to 16,384 tokens.
Which can read images, PDFs, audio or video?
GPT-5.5 accepts text, images and PDFs; GPT-5.3 Chat accepts text and images. GPT-5.5 handles the widest range of inputs.
Are any of these open source?
No. GPT-5.5 and GPT-5.3 Chat are proprietary and only available through APIs and apps.
Which is newer?
GPT-5.5 is the newest, released Apr 23, 2026. GPT-5.3 Chat came out Mar 3, 2026. Knowledge cutoff: GPT-5.5 Dec 1, 2025, GPT-5.3 Chat 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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