GPT-5.5 Instant vs o1
Pricing, benchmarks, and use case comparison
Quick take
- •GPT-5.5 Instant is meaningfully stronger at speed (92 vs 30 on our capability index).
- •o1 is meaningfully stronger at reasoning (90 vs 78).
- •GPT-5.5 Instant is 67% cheaper on input tokens, which compounds fast on high-volume or agentic workloads.
- •GPT-5.5 Instant has a 1050000 context window vs 200,000 tokens (100,000 max output) - better for whole-repo or long-document work.
Specs comparison
| GPT-5.5 Instant | o1 | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Type | Closed source | Closed source |
| Context window | ✓1050000 | 200,000 tokens (100,000 max output) |
| Input / 1M tokens | ✓5.00 | $15.00 |
| Output / 1M tokens | 30.00 | $60.00 |
| Release date | 2026-05 | 2024-12 |
Benchmarks
| Benchmark | GPT-5.5 Instant | o1 |
|---|---|---|
| AIME 2025 | 81.2 | - |
| Terminal-Bench 2.0 | 82.7 | - |
| FrontierMath Tier 1–3 | 51.7 | - |
| AIME 2024 | - | 74% |
| GPQA Diamond | - | 77.3% |
| Codeforces | - | ~89th percentile |
Scores sourced from official provider release posts and independent benchmark aggregators.
Which should you choose?
Choose GPT-5.5 Instant if...
- →Interactive chat and everyday assistant tasks where responsiveness matters most
- →High-volume, latency-sensitive workloads that do not need deep reasoning
- →General questions, drafting, and summarization at speed
Choose o1 if...
- →Hard, multi-step math, science, and logic problems that reward deliberate reasoning
- →Competitive programming and algorithmic problem solving
- →Existing o1-based pipelines already validated for reasoning tasks