THU, JULY 30, 2026
Independent · In‑Depth · Practitioner‑Tested
Large Language Models

Claude Sonnet 5 vs Opus 5 Before August 31 Deadline: Lock In $2/M vs Pay $5/M After

Sonnet 5 Intro Pricing Ends August 31 — What to Do Before the Deadline

🕐 5 min read 👁 14 views 📅 Jul 30, 2026

ACTION REQUIRED — AUGUST 31, 2026 DEADLINE

Sonnet 5 now (through Aug 31): $2/$10/M — 60% cheaper than Opus 5
Sonnet 5 after Aug 31: $3/$15/M — 40% cheaper than Opus 5
Opus 5 (unchanged): $5/$25/M
What to do before Aug 31: Run high-volume workloads on Sonnet 5, batch any large processing jobs, build and cache any high-cost context patterns
What changes Sept 1: Sonnet 5 becomes $3/M — still cheaper than Opus 5 but the gap narrows from 60% to 40%
When to use Opus 5 over Sonnet 5: Hard reasoning (ARC-AGI-3 30.2%), effort toggle (5-level), 128K output, Claude Max default

The intro pricing window closes August 31. If you have batch processing jobs, large-scale content generation, or any workload that can be front-loaded before the deadline, running them through Sonnet 5 at $2/M before September 1 saves 33% compared to the $3/M price after (or 60% compared to Opus 5). After the deadline: Sonnet 5 remains the right choice for writing, coding, and analysis that does not specifically need Opus 5's effort toggle or ARC-AGI-3 reasoning performance. The 40% price gap is still material for high-volume workloads.

Before August 31 — route to Sonnet 5: Content generation at volume, code review queues, batch document processing, RAG pipeline calls, any workload where quality difference from Opus 5 is marginal.

Use Opus 5 regardless of deadline: Tasks needing the effort toggle, extended reasoning (ARC-AGI-3 30.2%), very long outputs (128K), auto-fallback replacing hard refusals, and Claude Max sessions where Opus 5 is the default.

Last updated July 30, 2026. Related: Claude Opus 5 full review →

⚖ Our Verdict

Run high-volume work through Sonnet 5 before August 31 at $2/M — 60% cheaper than Opus 5. After Aug 31: Sonnet 5 moves to $3/M (40% cheaper than Opus 5). Use Opus 5 when you need the effort toggle, ARC-AGI-3 reasoning, 128K output, or Claude Max default. Batch any large processing jobs before the deadline.