ModelRefs / Claude 3.5 Sonnet vs Claude Sonnet 4.5
Claude 3.5 Sonnet vs Claude Sonnet 4.5
Claude 3.5 Sonnet vs Claude Sonnet 4.5: side-by-side benchmarks, pricing, context windows, coding ability and deployment. Pick the right model for your stack.
Overview
Claude 3.5 Sonnet: Claude 3.5 Sonnet is Anthropic's mid-2024 balanced model, the release that introduced computer use and anchored Anthropic's agentic-coding positioning for its generation across a 200,000-token context window. It is now retired: Anthropic deprecated both the claude-3-5-sonnet-20240620 and claude-3-5-sonnet-20241022 snapshots on 13 August 2025 and retired them on 28 October 2025 on Anthropic-operated platforms, naming Claude Sonnet 5.5 as the replacement.
Claude Sonnet 4.5: Claude Sonnet 4.5 is Anthropic's balanced frontier model, designed for complex reasoning, coding, and agentic tasks while maintaining production-grade speed. It builds on the Claude 4 family's emphasis on honesty and reduced hallucination rates.
Context window: Claude 3.5 Sonnet accepts up to 200,000 tokens, Claude Sonnet 4.5 up to 200,000. Confirm the limit for your specific deployment channel before relying on it.
Claude 3.5 Sonnet vs Claude Sonnet 4.5 at a glance
| Attribute | Claude 3.5 Sonnet | Claude Sonnet 4.5 |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Released | 2024-06-20 | 2025-09-29 |
| Context window | 200,000 tokens | 200,000 tokens |
| Input price | $3/M tokens | $3/M tokens |
| Output price | $15/M tokens | $15/M tokens |
| Licence | Proprietary | Proprietary |
| Self-hostable | No, hosted only | No, hosted only |
| Modalities | text, vision | text, vision |
Benchmarks reported for both
| Benchmark | Claude 3.5 Sonnet | Claude Sonnet 4.5 | Reported |
|---|---|---|---|
| SWE-Bench Verified (resolved) | 49 | 77.2 | 2025-01-06 / 2025-09-29 |
Each row compares the same benchmark, the same reported metric, and the same task set. Scores are as published by their cited sources on the dates shown. Different runs still use different harnesses and prompts, so treat these as directional evidence rather than a head-to-head result.
Where they differ most
- Coding: Claude 3.5 Sonnet 49%, Claude Sonnet 4.5 77%. Claude Sonnet 4.5 leads on this dimension.
- Agentic: Claude 3.5 Sonnet 49%, Claude Sonnet 4.5 66%. Claude Sonnet 4.5 leads on this dimension.
- Cost Efficiency: Claude 3.5 Sonnet 37%, Claude Sonnet 4.5 37%. Both score the same on this dimension.
Capability scores are ModelRefs' own derived signals, not vendor claims or benchmark results. Validate against your own workload before relying on them.
Continue your research
Use these connected ModelRefs sections to compare alternatives, inspect implementation paths, and review the evidence and governance boundaries relevant to Claude 3.5 Sonnet vs Claude Sonnet 4.5.
Frequently asked questions
Which is better, Claude 3.5 Sonnet or Claude Sonnet 4.5?
Claude 3.5 Sonnet and Claude Sonnet 4.5 target different workloads — see the benchmark and pricing tables for a side-by-side answer.
Is Claude 3.5 Sonnet cheaper than Claude Sonnet 4.5?
Compare $0.00300 vs $0.00300 on this page.