Model Comparison
GPT-5.4 nano (medium)
vs. GPT-5.5 Instant (May 2026)
Comparing 2 AI models · 7 benchmarks · OpenAI
Recommended Pick
Op GPT-5.5 Instant (May 2026) 10 metric wins Strongest on: TTFT, Latency, Reasoning
Best Value
GPT-5.4 nano (medium)
100.0 value score
40.3 reasoning / $0.46/1M
Lowest Price
GPT-5.4 nano (medium)
$0.20/1M input price
Best Reasoning
GPT-5.5 Instant (May 2026)
46.1 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-5.4 nano (medium) has the strongest quality-to-price mix at 100.0 out of 100 value points.
Price gap
GPT-5.4 nano (medium) is 25x cheaper on input tokens than GPT-5.5 Instant (May 2026).
Reasoning gap
GPT-5.5 Instant (May 2026) leads GPT-5.4 nano (medium) by 5.8 points on reasoning.
Coding gap
GPT-5.5 Instant (May 2026) leads GPT-5.4 nano (medium) by 10.1 points on coding.
Top-pick rationale
GPT-5.5 Instant (May 2026) wins 10 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-5.4 nano (medium)
OpenAI
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
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GPT-5.5 Instant (May 2026)
OpenAI
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
Which answer was more useful?
Full Comparison
| Metric | Op GPT-5.4 nano (medium) | Top Pick Op GPT-5.5 Instant (May 2026) |
|---|---|---|
| Pricing per 1M tokens | ||
| Input Cost | $0.20/1M | $5.00/1M |
| Output Cost | $1.25/1M | $30.00/1M |
| Blended (3:1) | $0.46/1M | $11.25/1M |
| Specifications | ||
| Organization | OpenAI | OpenAI |
| Release Date | Mar 17, 2026 | May 5, 2026 |
| Performance & Speed | ||
| Throughput | 165.7 tok/s | — |
| TTFT | 3574ms | — |
| Latency | 3574ms | — |
| Composite Indices | ||
| Value Score | 100.0 | 4.7 |
| Reasoning Score | 40.3 | 46.1 |
| Intelligence | 30.2 | 33.5 |
| Coding | 35.0 | 45.1 |
| Standard Benchmarks | ||
| GPQA | 76.1% | 84.6% |
| HLE | 14.7% | 20.3% |
| SciCode | 38.4% | 50.3% |
| LCR | 57.3% | 55.7% |
| IFBench | 64.4% | 71.5% |
| TAU-bench v2 | 52.6% | 49.4% |
| TerminalBench Hard | 33.3% | 42.4% |
Key Takeaways
GPT-5.4 nano (medium) offers the best value at $0.20/1M, making it ideal for high-volume applications and cost-conscious projects.
GPT-5.5 Instant (May 2026) has the strongest reasoning profile with a 46.1 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-5.4 nano (medium)
- Cost-sensitive applications
- High-volume processing
GPT-5.5 Instant (May 2026)
- Complex reasoning tasks
- Research & analysis
- Code generation
- Software development
