Claude Opus 4.8 vs Claude Sonnet 4.6

Both models are Anthropic's current production family on the Anthropic API, AWS Bedrock, and Google Vertex AI with a shared 1M-token context window. The choice is a cost-vs-capability trade: Claude Sonnet 4.6 costs $3/M input and $15/M output with a 64K max output; Claude Opus 4.8 costs $5/M input and $25/M output with a 128K max output, a stronger benchmark profile across SWE-bench, GPQA, and LiveCodeBench, and a Fast Mode research preview at $10/M input and $50/M output for latency-sensitive workloads.

Pick Claude Opus 4.8 when agentic coding quality, long-horizon reasoning, or computer-use accuracy is the primary constraint: it leads SWE-bench Verified 88.6% vs 79.6%, SWE-bench Pro 69.2%, GPQA Diamond 93.6% vs 89.9%, LiveCodeBench 88.8% vs 80%, and has a 128K vs 64K max output ceiling. Pick Claude Sonnet 4.6 when cost or throughput is the bottleneck: it is 40% cheaper on input and output tokens while sharing the same 1M context window, provider availability, prompt caching, Batch API support, and multimodal capabilities. Default to Sonnet 4.6 for high-volume pipelines, summarization, and JSON / Tool use agents where benchmark gaps do not visibly affect quality; upgrade to Opus 4.8 for SWE-bench-class coding agents, multi-step computer-use tasks, and hard-science reasoning where the ~9-point benchmark gap translates to real outcome differences.

Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.