# GPT-5.5 vs Kimi K2.5

On provider list prices, Kimi K2.5 costs $0.50 per million input tokens against $5 for GPT-5.5: 10.0x apart. Output is $2.80 against $30 (10.7x).

## Specifications

| | GPT-5.5 | Kimi K2.5 |
| --- | --- | --- |
| Lab | OpenAI | Togethercomputer |
| Access | API only | Open weights |
| Context window | 400K tokens | 256K tokens |
| List price, input | $5 / M tokens | $0.50 / M tokens |
| List price, output | $30 / M tokens | $2.80 / M tokens |
| Cached input | $0.50 / M tokens | n/a |
| License | Proprietary API | Not listed |
| Fine-tunable | No | Yes |

Specifications and provider list prices from the Allocate catalog, checked 2026-07-21.

## What the numbers say

Take 1,000,000 requests a month at 1,200 input and 350 output tokens each. That workload costs $1,580 a month on Kimi K2.5 and $16,500 on GPT-5.5 at list: a gap of $14,920, or 10.4x.

GPT-5.5 reads 400K tokens per request against 256K for Kimi K2.5, 1.5x 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 Kimi K2.5 for

- Whole-document reasoning
- Long-context retrieval
- Open-weight fine-tuning

## Common questions

### Which is cheaper, GPT-5.5 or Kimi K2.5?

Kimi K2.5, on this workload shape. At list prices it is $0.50/$2.80 per million tokens in and out against $5/$30 for GPT-5.5. Billed on Allocate: $0.54/$3.00 against $5.35/$32.10.

### Which has the bigger context window?

GPT-5.5: 400,000 tokens (400K) against 262,144 (256K) for Kimi K2.5.

### Can I fine-tune GPT-5.5 or Kimi K2.5?

Kimi K2.5 publishes open weights (Not listed) 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-kimi-k2-5) · [GPT-5.5](https://allocate.network/models/gpt-5-5.md) · [Kimi K2.5](https://allocate.network/models/kimi-k2-5.md) · [Machine-readable catalog](https://allocate.network/catalog.json)