Model Comparison
GPT-5.5 Instant (May 2026)
vs. GPT-5 (ChatGPT)
Comparing 2 AI models · 10 benchmarks · OpenAI
Recommended Pick
Op GPT-5.5 Instant (May 2026) 11 metric wins Strongest on: TTFT, Latency, Reasoning
Best Value
GPT-5 (ChatGPT)
100.0 value score
38.6 reasoning / $3.44/1M
Lowest Price
GPT-5 (ChatGPT)
$1.25/1M input price
Best Reasoning
GPT-5.5 Instant (May 2026)
48.9 reasoning score
Blends available reasoning benchmarks
Best for Coding
GPT-5.5 Instant (May 2026)
45.1 coding index
Composite Indices
Higher is better; speed and price are normalized
Standard Benchmarks
Only benchmarks with data are shown
Differences That Matter
Best value
GPT-5 (ChatGPT) has the strongest quality-to-price mix at 100.0 out of 100 value points.
Price gap
GPT-5 (ChatGPT) is 4.0x cheaper on input tokens than GPT-5.5 Instant (May 2026).
Reasoning gap
GPT-5.5 Instant (May 2026) leads GPT-5 (ChatGPT) by 10.3 points on reasoning.
Coding gap
GPT-5.5 Instant (May 2026) leads GPT-5 (ChatGPT) by 23.9 points on coding.
Top-pick rationale
GPT-5.5 Instant (May 2026) wins 11 measurable categories, including TTFT, Latency, Reasoning, Intelligence.
Response Face-Off
Run one prompt through the selected models and compare response quality with live speed and cost context.
GPT-5.5 Instant (May 2026)
OpenAI
TTFT
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Time
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tok/s
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Tokens
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Cost
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GPT-5 (ChatGPT)
OpenAI
TTFT
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Time
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tok/s
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Tokens
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Cost
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Which answer was more useful?
Full Comparison
| Metric | Top Pick Op GPT-5.5 Instant (May 2026) | Op GPT-5 (ChatGPT) |
|---|---|---|
| Pricing per 1M tokens | ||
| Input Cost | $5.00/1M | $1.25/1M |
| Output Cost | $30.00/1M | $10.00/1M |
| Blended (3:1) | $11.25/1M | $3.44/1M |
| Specifications | ||
| Organization | OpenAI | OpenAI |
| Release Date | May 5, 2026 | Aug 7, 2025 |
| Performance & Speed | ||
| Throughput | — | 181.3 tok/s |
| TTFT | — | 512ms |
| Latency | — | 512ms |
| Composite Indices | ||
| Value Score | 38.7 | 100.0 |
| Reasoning Score | 48.9 | 38.6 |
| Intelligence | 41.8 | 21.8 |
| Coding | 45.1 | 21.2 |
| Math | — | 48.3 |
| Standard Benchmarks | ||
| GPQA | 84.6% | 68.6% |
| MMLU Pro | — | 82.0% |
| HLE | 20.3% | 5.8% |
| LiveCodeBench | — | 54.3% |
| AIME 2025 | — | 48.3% |
| SciCode | 50.3% | 37.8% |
| LCR | 55.7% | 63.7% |
| IFBench | 71.5% | 45.0% |
| TAU-bench v2 | 49.4% | 0.0% |
| TerminalBench Hard | 42.4% | 12.9% |
Key Takeaways
GPT-5 (ChatGPT) offers the best value at $1.25/1M, making it ideal for high-volume applications and cost-conscious projects.
GPT-5.5 Instant (May 2026) has the strongest reasoning profile with a 48.9 reasoning score, combining the available reasoning-heavy benchmarks.
GPT-5.5 Instant (May 2026) reaches a 45.1 coding index, making it the top choice for software development and code generation tasks.
All models support context windows of ∞+ tokens, suitable for processing lengthy documents and maintaining extended conversations.
When to Choose Each Model
GPT-5.5 Instant (May 2026)
- Complex reasoning tasks
- Research & analysis
- Code generation
- Software development
GPT-5 (ChatGPT)
- Cost-sensitive applications
- High-volume processing
