Claude Sonnet 5 vs Claude Opus 4.8
Claude Sonnet 5 landed June 30, 2026 as Anthropic's most agentic Sonnet-class model, and its introductory $2 input / $10 output pricing through August 31 puts it at roughly 40 percent of Opus 4.8's $5 / $25. On several agentic benchmarks Sonnet 5 gets close to, and in one case beats, the current flagship: Anthropic's own numbers put Sonnet 5 at 80.4 on Terminal-Bench 2.1 (vs Opus 4.8 at 74.6), 85.2 on SWE-bench Verified (vs 88.6), 63.2 on SWE-bench Pro (vs 69.2), and 81.2 on OSWorld-Verified (vs 83.4). Opus 4.8 still wins on the hardest reasoning and knowledge-work tasks, but Sonnet 5 is now the default choice for cost-sensitive agentic pipelines, and for most coding workloads it is the model you should try first.
Head-to-Head Specs
| Spec | Claude Sonnet 5 | Claude Opus 4.8 |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Input Price | $2.00/1M | $5.00/1M |
| Output Price | $10.00/1M | $25.00/1M |
| Context Window | 1M | 1M |
| Released | 2026-06 | 2026-05 |
| Capabilities | text, vision, tool-use, code, reasoning | text, vision, tool-use, code |
Benchmark Scores
| Benchmark | Claude Sonnet 5 | Claude Opus 4.8 | Winner |
|---|---|---|---|
| SWE-bench | 85.2 | 88.6 | Claude |
See the full benchmark leaderboard for all models.
Category Breakdown
Sonnet 5 costs $2/$10 through August 31, 2026 vs Opus 4.8 at $5/$25 per 1M tokens
Sonnet 5 scores 80.4 vs Opus 4.8 at 74.6, an actual capability win for the cheaper model
Opus 4.8 posts 88.6 vs Sonnet 5 at 85.2
Opus 4.8 posts 69.2 vs Sonnet 5 at 63.2
Opus 4.8 posts 83.4 vs Sonnet 5 at 81.2 on computer use
Both ship a 1 million token context window (Sonnet 5 adds context compaction)
Both support adaptive thinking; Sonnet 5 goes up to xhigh effort
Both are on Claude API, Amazon Bedrock, Google Vertex, and Microsoft Foundry
Choose Claude Sonnet 5 when:
- ▸Cost-sensitive agentic coding pipelines
- ▸Terminal-Bench and shell-agent workloads where Sonnet 5 actually beats Opus
- ▸High-volume production RAG and knowledge work
- ▸New deployments during the introductory pricing window
Choose Claude Opus 4.8 when:
- ▸Hardest whole-repository refactors where the SWE-bench delta matters
- ▸Computer-use agents where the extra 2.2 points on OSWorld pays for itself
- ▸Existing prompts and evals already tuned to Opus 4.8 behavior
- ▸Workloads where the top of Opus's reasoning ceiling justifies the price
Frequently Asked Questions
Which is better, Claude Sonnet 5 or Claude Opus 4.8?
It depends on your use case. Claude Sonnet 5 from Anthropic excels at cost-sensitive agentic coding pipelines, while Claude Opus 4.8 from Anthropic is better for hardest whole-repository refactors where the swe-bench delta matters. See the full comparison above for detailed benchmarks and pricing.
How much does Claude Sonnet 5 cost compared to Claude Opus 4.8?
Claude Sonnet 5 costs $2.00 input and $10.00 output per 1M tokens. Claude Opus 4.8 costs $5.00 input and $25.00 output per 1M tokens.
What is the context window difference between Claude Sonnet 5 and Claude Opus 4.8?
Claude Sonnet 5 supports 1M tokens, while Claude Opus 4.8 supports 1M tokens.