# GPT-5.5 vs OpenAI GPT-OSS 20B

On provider list prices, OpenAI GPT-OSS 20B costs $0.05 per million input tokens against $5 for GPT-5.5: 100.0x apart. Output is $0.20 against $30 (150.0x). On Allocate both bill at list plus the 7% transaction fee.

## Specifications

| | GPT-5.5 | OpenAI GPT-OSS 20B |
| --- | --- | --- |
| Lab | OpenAI | OpenAI |
| Access | API only | Open weights |
| Context window | 400K tokens | 128K tokens |
| List price, input | $5 / M tokens | $0.05 / M tokens |
| List price, output | $30 / M tokens | $0.20 / M tokens |
| Cached input | $0.50 / M tokens | n/a |
| License | Proprietary API | Apache 2.0 |
| Fine-tunable | No | Yes |

Specifications and provider list prices from the Allocate catalog, checked 2026-07-08. Billed price is list plus the 7% transaction fee.

## What the numbers say

Take 1,000,000 requests a month at 1,200 input and 350 output tokens each. That workload costs $130 a month on OpenAI GPT-OSS 20B and $16,500 on GPT-5.5 at list: a gap of $16,370, or 126.9x.

GPT-5.5 reads 400K tokens per request against 128K for OpenAI GPT-OSS 20B, 3.1x the window. That decides which one can take whole documents without splitting them.

## Choose GPT-5.5 for

- Complex tool-using agents
- Code generation
- General assistants

## Choose OpenAI GPT-OSS 20B for

- The lower list price ($0.05 in / $0.20 out per M tokens)
- Open weights you can fine-tune and own
- Fine-tuning under a permissive license (Apache 2.0)

## Common questions

### Which is cheaper, GPT-5.5 or OpenAI GPT-OSS 20B?

OpenAI GPT-OSS 20B, on this workload shape. At list prices it is $0.05/$0.20 per million tokens in and out against $5/$30 for GPT-5.5. Billed on Allocate: $0.053/$0.21 against $5.35/$32.10, list plus 7%.

### Which has the bigger context window?

GPT-5.5: 400,000 tokens (400K) against 131,072 (128K) for OpenAI GPT-OSS 20B.

### Can I fine-tune GPT-5.5 or OpenAI GPT-OSS 20B?

OpenAI GPT-OSS 20B publishes open weights (Apache 2.0) and can be fine-tuned on your own data. GPT-5.5 is a closed model served over API; its weights are not available.

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[HTML page](https://allocate.network/compare/gpt-5-5-vs-openai-gpt-oss-20b) · [GPT-5.5](https://allocate.network/models/gpt-5-5.md) · [OpenAI GPT-OSS 20B](https://allocate.network/models/openai-gpt-oss-20b.md) · [Machine-readable catalog](https://allocate.network/catalog.json)