GPT-5.5 vs GPT-5.6
Pricing, benchmarks, and use case comparison
Quick take
- •GPT-5.6 is meaningfully stronger at cost efficiency (70 vs 58).
Specs comparison
| GPT-5.5 | GPT-5.6 | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Type | Closed source | Closed source |
| Context window | ✓1,050,000 tokens (128,000 max output) | Not announced |
| Input / 1M tokens | $5.00 | 5 |
| Output / 1M tokens | $30.00 | 30 |
| Release date | 2026-04 | 2026-06 |
Benchmarks
| Benchmark | GPT-5.5 | GPT-5.6 |
|---|---|---|
| SWE-bench Verified | 82.6% | - |
| SWE-bench Pro | 58.6% | - |
| Terminal-Bench 2.1 (Sol) | - | 88.8% |
| Terminal-Bench 2.1 (Terra) | - | 82.5% |
| Terminal-Bench 2.1 (Luna) | - | 84.3% |
| Terminal-Bench 2.1 | - | 88.8 |
| ExploitBench | - | Competitive with Anthropic Mythos Preview |
| ExploitGym | - | Significant improvements |
| GeneBench v1 | - | Not announced |
Scores sourced from official provider release posts and independent benchmark aggregators.
Which should you choose?
Choose GPT-5.5 if...
- →Complex professional coding, data analysis, and multi-tool agentic workflows
- →Long-document or large-codebase tasks needing a 1M+ context window
- →You want OpenAI's recommended default frontier model for new projects
Choose GPT-5.6 if...
- →You want to standardize on one model generation but route requests across cost/quality tiers
- →You are an approved preview partner exploring the newest OpenAI capabilities
- →Workloads spanning agentic coding, knowledge work, and research where tier flexibility helps