gpt-oss-120b Open vs 
Claude Sonnet 5.5 Paid
gpt-oss-120b vs Claude Sonnet 5.5 compared — price per token, context window, multimodality, openness and which to choose. Can the open-source model replace the paid one? Full 2026 breakdown.
Claude Sonnet 5.5 — full profile ›
Prices & specs refreshed from live data · olud.ai
Open-model prices = cheapest provider via OpenRouter; official maker rates may be higher.
$0.17 /M outputNo per-token fees if you self-host
$10 /M outputManaged API (no infra to run)
gpt-oss-120b vs Claude Sonnet 5.5 specs
| Spec | gpt-oss-120b | Claude Sonnet 5.5 | Winner |
|---|---|---|---|
| Maker | OpenAI | Anthropic | – |
| Type | Open-weight | Proprietary | |
| Context window | 131K tokens | 1M tokens | |
| Input price | $0.04/M · free self-host | $2/M | |
| Output price | $0.17/M · free self-host | $10/M | |
| Vision / multimodal | No | Yes | |
| Tool / function calling | Yes | Yes | = Tie |
| Self-hostable | Yes | No (API only) | |
| License | Apache 2.0 | Proprietary |
Price gap & when to choose each
gpt-oss-120b is ~59× cheaper than Claude Sonnet 5.5 on output tokens ($0.17 vs $10 per M tokens).
- You want to self-host or run on your cloud
- You prioritize data privacy & control
- You want the lowest operating costs
- You are building open or reproducible AI
- You want frontier performance through a managed API
- You need the longer 1M context window
- You value reliability & ecosystem
- You don't want to manage infrastructure
Feature comparison
| Capability | gpt-oss-120b | Claude Sonnet 5.5 |
|---|---|---|
| Open weights (downloadable) | ✓ | ✗ |
| Self-hostable | ✓ | ✗ |
| Runs fully offline | ✓ | ✗ |
| Vision / multimodal | ✗ | ✓ |
| Tool / function calling | ✓ | ✓ |
| 1M+ context window | ✗ | ✓ |
Benchmarks: gpt-oss-120b vs Claude Sonnet 5.5
Independent benchmark scores measured by Artificial Analysis. Higher is better (except latency).
Benchmark data by Artificial Analysis.
How gpt-oss-120b and Claude Sonnet 5.5 score
| Criterion | gpt-oss-120b | Claude Sonnet 5.5 |
|---|---|---|
| Cost-efficiency | 5.0 | 3.5 |
| Context window | 3.5 | 5.0 |
| Openness | 5.0 | 1.5 |
| Self-hosting | 5.0 | 1.0 |
| Multimodality | 3.5 | 5.0 |
Scores come from live data — output price (cost), context length, open vs closed weights (openness & self-hosting) and vision/tool support (multimodality). Raw task quality isn't scored here; it depends on your benchmark — see the verdict.
What each model is
gpt-oss-120b Open
gpt-oss-120b is an open-weight, 117B-parameter Mixture-of-Experts (MoE) language model from OpenAI designed for high-reasoning, agentic, and general-purpose production use cases. It activates 5.1B parameters per forward pass and is optimize
Claude Sonnet 5.5 Paid
Claude Sonnet 5.5 is Anthropic's Sonnet-class model for well-scoped everyday work, succeeding Claude Sonnet 5 as a direct upgrade. It is especially strong at building features, fixing bugs, and producing...
Other models in these families
These variants are tracked but not compared here — one page per family keeps the comparison readable.
Frequently asked questions
Is gpt-oss-120b as good as Claude Sonnet 5.5?
gpt-oss-120b is open-weight and competitive on many tasks, but Claude Sonnet 5.5 may still lead on the hardest reasoning and agentic work. The gap keeps narrowing — benchmark both on your actual use case before deciding.
Can I run gpt-oss-120b locally?
Yes. gpt-oss-120b has open weights, so you can self-host it on your own GPUs or run it via a low-cost API. Claude Sonnet 5.5 is API-only and cannot be self-hosted.
How much cheaper is gpt-oss-120b?
gpt-oss-120b costs $0.17/M output vs $10/M for Claude Sonnet 5.5 — roughly 59x cheaper via API, and free if you self-host.
gpt-oss-120b vs Claude Sonnet 5.5 — which should I pick in 2026?
Choose gpt-oss-120b if you want to self-host, keep your data private and skip per-token fees — it's open-weight and runs on your own hardware. Choose Claude Sonnet 5.5 if you want frontier capability through a managed API with zero infrastructure to run.
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