GPT-4o vs GPT-5.5
2026 - Pricing, benchmarks, and use case comparison
Quick take
- •GPT-5.5 is open-weights - free to self-host with no API costs. GPT-4o requires paid API access.
- •Both models come from OpenAI. GPT-4o targets higher capability; GPT-5.5 is the faster, cheaper tier.
Specs comparison
| GPT-4o | GPT-5.5 | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Type | Closed source | Closed source |
| Context window | 128K | 128K |
| Input / 1M tokens | $2.50 | ✓Free (self-host) |
| Output / 1M tokens | $10.00 | Free (self-host) |
| Release date | 2024-05 | 2026-04 |
Benchmarks
| Benchmark | GPT-4o | GPT-5.5 |
|---|---|---|
| MMLU | 88.7% | - |
| HumanEval | 90.2% | - |
| GPQA | 53.6% | - |
Scores sourced from official provider release posts.
Strengths
GPT-4o
- ✓Native multimodal input (text, image, audio)
- ✓Fast response times at this capability level
- ✓Strong on structured data and JSON output
- ✓Best ecosystem support across SDKs and tools
- ✓Real-time audio capabilities
GPT-5.5
- ✓Improved instruction following over GPT-4o
- ✓Stronger long-context coherence
- ✓Better output consistency for agentic pipelines
- ✓GPT-5.5 Pro tier for reliability-critical workloads
- ✓Easier migration path than jumping from GPT-4o to GPT-5
Which should you choose?
Choose GPT-4o if you need...
- →Multimodal apps
- →High-volume production use
- →Chatbots and assistants
- →Structured data extraction
Choose GPT-5.5 if you need...
- →Production API integrations migrating from GPT-4o
- →Agentic workflows needing consistent structured output
- →Long-context document tasks
- →Teams deferring full GPT-5 migration costs