GPT-4o vs GPT-5.5 Instant
Pricing, benchmarks, and use case comparison
Quick take
- •GPT-4o is meaningfully stronger at cost efficiency (82 vs 70 on our capability index).
- •GPT-5.5 Instant is meaningfully stronger at long context (80 vs 55).
- •GPT-4o is 50% cheaper on input tokens, which compounds fast on high-volume or agentic workloads.
- •GPT-5.5 Instant has a 1050000 context window vs 128,000 tokens (16,384 max output) - better for whole-repo or long-document work.
Specs comparison
| GPT-4o | GPT-5.5 Instant | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Type | Closed source | Closed source |
| Context window | 128,000 tokens (16,384 max output) | ✓1050000 |
| Input / 1M tokens | ✓$2.50 | 5.00 |
| Output / 1M tokens | $10.00 | 30.00 |
| Release date | 2024-05 | 2026-05 |
Benchmarks
| Benchmark | GPT-4o | GPT-5.5 Instant |
|---|---|---|
| MMLU | 88.7% | - |
| HumanEval | 90.2% | - |
| MATH | 76.6% | - |
| AIME 2025 | - | 81.2 |
| Terminal-Bench 2.0 | - | 82.7 |
| FrontierMath Tier 1–3 | - | 51.7 |
Scores sourced from official provider release posts and independent benchmark aggregators.
Which should you choose?
Choose GPT-4o if...
- →Everyday assistant, drafting, summarization, and classification tasks
- →Latency- and cost-sensitive applications at scale
- →Multimodal tasks needing image understanding with fast responses
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