# Claude Sonnet 5 vs Claude Sonnet 5.5

As of October 21, 2026, Claude Sonnet 5 and Claude Sonnet 5.5 cost the same: $2.00 per 1M input tokens and $10.00 per 1M output tokens, and both have a 1M-token context window.

- Page: https://models.litellm.ai/compare/claude-sonnet-5-vs-claude-sonnet-5-5
- Claude Sonnet 5: https://models.litellm.ai/models/claude-sonnet-5
- Claude Sonnet 5.5: https://models.litellm.ai/models/claude-sonnet-5-5

## Side by side

| | Claude Sonnet 5 | Claude Sonnet 5.5 |
|---|---|---|
| Input, per 1M tokens | $2.00 | $2.00 |
| Output, per 1M tokens | $10.00 | $10.00 |
| Cache read, per 1M tokens | $0.20 | $0.10 |
| Cache write, per 1M tokens | $2.50 | $2.50 |
| Context window | 1,000,000 tokens | 1,000,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Image input | Yes | Yes |
| Tool calling | Yes | Yes |
| Structured output (JSON) | Yes | Yes |
| Prompt caching | Yes | Yes |
| Reasoning | Yes | Yes |
| Providers on LiteLLM | 9 | 7 |
| Price shown is from | Anthropic | Anthropic |
| Added to LiteLLM | June 30, 2026 | September 28, 2026 |

Headline prices in USD per 1M tokens, from LiteLLM's model price file.

## Cheapest provider for each

- Claude Sonnet 5: Anthropic at $2.00 input per 1M tokens (`claude-sonnet-5`)
- Claude Sonnet 5.5: Anthropic at $2.00 input per 1M tokens (`claude-sonnet-5-5`)

## Benchmark scores

| Benchmark | Claude Sonnet 5 | Claude Sonnet 5.5 |
|---|---|---|
| Epoch Capabilities Index (Overall) | 156.9 | 166.2 |
| FrontierCode (Coding and agents) | 42.7% | 52.1% (xhigh) |
| APEX-Agents (Coding and agents) | 54.5% | 75.5% (max) |
| GPQA Diamond (Reasoning and knowledge) | 90.5% (xhigh) | 95.6% (max) |
| SimpleQA Verified (Reasoning and knowledge) | 33.7% (max) | 46.5% (max) |
| FrontierMath (tiers 1-3) (Math) | 65.6% (max) | 88.8% (max) |
| FrontierMath (tier 4) (Math) | 29.3% (max) | 80.5% (max) |
| OTIS Mock AIME 2024-2025 (Math) | 94.7% (xhigh) | 100.0% (max) |

From the Epoch AI Benchmarking Hub (https://epoch.ai/benchmarks), CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/), data as of September 29, 2026: Epoch's own runs and results it collects from each benchmark's leaderboard. Higher is better.

## FAQ

### Which is cheaper, Claude Sonnet 5 or Claude Sonnet 5.5?

They cost the same: $2.00 per 1M input tokens and $10.00 per 1M output tokens, as of October 21, 2026.

### Which has the larger context window, Claude Sonnet 5 or Claude Sonnet 5.5?

Both have a 1,000,000-token context window.

### Can I switch from Claude Sonnet 5 to Claude Sonnet 5.5 without changing my code?

Yes. Through LiteLLM both use the OpenAI format, so switching means changing the model name from "claude-sonnet-5" to "claude-sonnet-5-5", or pointing a LiteLLM gateway model alias at the other model. You can also use one as a fallback for the other.