QUICK VERDICT — JULY 28, 2026
● Cheaper (intro pricing through Aug 31): Sonnet 5 — $2/$10/M vs Opus 5 $5/$25/M (60% cheaper input)
● Cheaper (after Aug 31): Sonnet 5 — $3/$15/M vs Opus 5 $5/$25/M (40% cheaper input)
● Better effort control: Opus 5 only — 5-level toggle
● Better for hard reasoning: Opus 5 — ARC-AGI-3 30.2% (Sonnet 5 not published)
● Better for writing and coding at lower cost: Sonnet 5 — strong output, cheaper
● Claude Max default: Opus 5 (as of July 24)
● Claude Pro: Both available — Opus 5 is now the strongest Pro model
● Intro pricing deadline: Sonnet 5 at $2/$10/M ends August 31, 2026
| Feature | Claude Opus 5 | Claude Sonnet 5 |
|---|
| Input /1M (current) | $5 | $2 (intro) |
| Input /1M (after Aug 31) | $5 | $3 |
| Effort toggle | 5-level | None |
| ARC-AGI-3 | 30.2% | Not published |
| Claude Max default | Yes (Jul 24) | No |
Claude Sonnet 5 for: Cost-sensitive high-volume workloads, writing, coding, and analysis tasks where the 5-level effort toggle is not required. Lock in usage before August 31 at $2/M if you have a high-volume use case — the intro pricing window is closing.
Claude Opus 5 for: Hard reasoning tasks that benefit from the effort toggle, long-form output (128K), Claude Max default (no settings change needed), and agentic workflows with auto-fallback replacing hard refusals. The right model once Sonnet 5 intro pricing ends and the gap narrows to 40%.
Last updated July 28, 2026. Related: Claude Opus 5 full review → · Claude Opus 5 vs Fable 5 →
⚖ Our Verdict
Sonnet 5 wins on price (60% cheaper now at $2/M intro, 40% cheaper after Aug 31 at $3/M). Opus 5 wins on reasoning (ARC-AGI-3 30.2%), effort control (5-level toggle), and Claude Max default. Use Sonnet 5 for high-volume writing/coding at lower cost. Use Opus 5 for hard reasoning, long output (128K), and agentic workflows. Sonnet 5 intro pricing ($2/M) ends August 31 — lock in high-volume usage before then.