Claude Opus 4.8 vs Claude Sonnet 5
Pricing, benchmarks, and use case comparison
Verdict
Our pick: Claude Sonnet 5Pick Claude Opus 4.8 for the hardest long-horizon coding and highest accuracy; pick Claude Sonnet 5 for near-Opus quality at roughly one-third to one-half the cost and faster responses.
Specs comparison
| Claude Opus 4.8 | Claude Sonnet 5 | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Type | Closed source | Closed source |
| Context window | 1M | 1M |
| Input / 1M tokens | $5.00 | ✓$3.00 |
| Output / 1M tokens | $25.00 | $15.00 |
| Release date | 2026-05 | 2026-06 |
Benchmarks
| Benchmark | Claude Opus 4.8 | Claude Sonnet 5 |
|---|---|---|
| SWE-bench Verified | ✓88.6% | ~85.2% |
| SWE-bench Pro | ✓69.2% | 63.2% |
| Terminal-Bench 2.1 | 74.6% | ✓80.4% |
| GPQA Diamond | 93.6% | - |
| Artificial Analysis Intelligence Index | 61.4 | - |
| OSWorld-Verified | - | 81.2% |
Scores sourced from official provider release posts and independent benchmark aggregators.
Capability and benchmarks
Opus 4.8 is the stronger model overall: 88.6% SWE-bench Verified, 69.2% SWE-bench Pro, and 93.6% GPQA Diamond, versus Sonnet 5's ~85.2% SWE-bench Verified and 63.2% SWE-bench Pro. Interestingly, Sonnet 5 beats Opus on Terminal-Bench 2.1 (80.4% vs 74.6%) and posts 81.2% on OSWorld-Verified for computer use. So Opus leads on the hardest end-to-end coding and science, while Sonnet 5 is remarkably close and even ahead on terminal-agent and computer-use tasks.
Price and context
Both share a 1M-token context and 128k output, and both use adaptive-only thinking (manual thinking budgets and custom sampling return 400 errors). The gap is price: Opus 4.8 is $5/$25 while Sonnet 5 is $3/$15 standard, with $2/$10 introductory pricing through August 31, 2026. Anthropic positions Sonnet 5 as approaching Opus 4.8 quality at roughly one-third to one-half the price, and Sonnet is faster (capability speed 82 vs 68).
Which to pick
- Pick Opus 4.8 for long-running autonomous agents on complex, high-value tasks, and where its honesty edge and top SWE-bench Pro score justify the premium.
- Pick Sonnet 5 for high-volume agent loops, general coding, and cost-sensitive production where you want the best capability per dollar. For most teams Sonnet 5 is the default and Opus 4.8 is the escalation tier.
Which should you choose?
Choose Claude Opus 4.8 if...
- →You need top-tier autonomous coding and multi-step agentic reliability
- →You run long-horizon agent traces that previously derailed after compaction
- →You want enterprise-grade reasoning with 1M context and 128k output
- →You need throughput and are willing to pay fast-mode premium for 2.5x speed
Choose Claude Sonnet 5 if...
- →You want frontier-adjacent agentic coding but need better cost-efficiency than Opus
- →You are running high-volume agent loops and want strong reasoning per dollar
- →You are already on Sonnet 4.6 and want a same-price capability upgrade
- →You need a 1M context window with fast latency