Claude Opus 5 vs Claude Sonnet 5.5.
Verdict by category, tale of the tape, shared benchmarks only, and cost at three workloads — all from the tracked data.
Verdict by category
| Category | Claude Opus 5 | Claude Sonnet 5.5 | Winner |
|---|---|---|---|
| League Score | 91.7 | 86.9 | Claude Opus 5 |
| Coding (SWE-bench %) | 96.0 | — | — |
| Reasoning (GPQA %) | 93.2 | — | — |
| Context (tokens) | 1000000 | 1000000 | Draw |
| Speed (tok/s) | — | — | — |
| Price (blended $/1M) | $10.00 | $4.00 | Claude Sonnet 5.5 (cheaper) |
Tale of the tape
| Spec | Claude Opus 5 | Claude Sonnet 5.5 |
|---|---|---|
| Maker | Anthropic | Anthropic |
| Released | Jul 24, 2026 | Sep 28, 2026 |
| League Score | 92 | 87 |
| Context | 1,000,000 tokens | 1,000,000 tokens |
| Max output | 128,000 | 128,000 |
| $/1M input | $5.00 | $2.00 |
| $/1M output | $25.00 | $10.00 |
| Weights | Closed | Closed |
| Speed | — | — |
Head-to-head benchmarks (shared only)
| Benchmark | Claude Opus 5 | Claude Sonnet 5.5 |
|---|---|---|
| LiveBench overall | 82.1 | 82.5 |
Cost at three workloads
| Workload | Claude Opus 5 | Claude Sonnet 5.5 |
|---|---|---|
| Light — 1M in / 250K out | $11.25 | $4.50 |
| Standard — 10M in / 2.5M out | $112.50 | $45.00 |
| Long-context — 50M in / 5M out | $375.00 | $150.00 |
The pick
Pick Claude Opus 5 if you want the higher overall League Score; coding is the priority.
Pick Claude Sonnet 5.5 if you want the lower running cost.
All figures from the model database — sources and dates on each model page. Cost your own workload or compare a different pair.
Frequently asked questions
Which is better overall, Claude Opus 5 or Claude Sonnet 5.5?
Claude Opus 5 leads on overall League Score, 92 to 87 — a gap of 5 points on a composite of sourced benchmarks. That is overall form, not every category: check the per-category verdicts before choosing.
Which is cheaper, Claude Opus 5 or Claude Sonnet 5.5?
Claude Sonnet 5.5 is cheaper: $4.00 vs $10.00 blended per 1M tokens (3:1 input/output mix) — about 2.5x less per token.
Which has the bigger context window, Claude Opus 5 or Claude Sonnet 5.5?
Neither — both take 1M of context.
Are Claude Opus 5 and Claude Sonnet 5.5 open source?
Claude Opus 5 is closed weights — API access only; Claude Sonnet 5.5 is closed weights — API access only.