Claude Opus 4.7 vs Sonnet 4 (May 2026)
TL;DR: Use Sonnet by default; it's ~2x faster, 40% cheaper, and within striking distance of Opus on quality. Route to Opus for the hardest 10-20% of requests.
Spec comparison
| Spec | Claude Opus 4.7 | Claude Sonnet 4 |
|---|---|---|
| Tier | Flagship. top of Anthropic line | Workhorse, Anthropic's default |
| API input / output per 1M | $5 / $25 | $3 / $15 |
| Cached input per 1M | $0.50 | $0.30 |
| Context window | 500K | 1M |
| Best raw quality | Yes: Arena coding #1 @ 1567 Elo | Close second; strong on long-context |
| Latency | Slower (deeper reasoning) | ~2x faster on most workloads |
| Tool use / agentic | Best in class, and strongest planning | Excellent. production default for agents |
| Long-context retrieval | Strong | Strongest, 1M context |
| Best for | Hardest coding, multi-step reasoning, planning | Most production workloads, long-context RAG |
Cost scenarios
| Workload | Opus 4.7 | Sonnet 4 |
|---|---|---|
| 1M tokens in, 100K tokens out | $5.00 + $2.50 = $7.50 | $3.00 + $1.50 = $4.50 |
| 10M tokens in (90% cached), 1M out | $0.50 + $25.00 = $25.50 | $0.30 + $15.00 = $15.30 |
| Agent loop: 50K context × 8 turns × 1K out each | ~$10 | ~$6 |
| Long-context RAG; 800K context, 5K out | N/A (>500K) | $2.40 + $0.08 = $2.48 |
The routing rule that wins
The pattern most production teams settle on: Sonnet by default; promote to Opus only on a small set of triggers, and task complexity score above threshold, multi-step planning detected, or the prompt is in a whitelist (codebase migration, complex refactor, novel reasoning). With a gateway this is a config block:
route:
default: anthropic/claude-sonnet-4
promote_to: anthropic/claude-opus-4-7
promote_when:
- intent: code_refactor
- intent: multi_step_planning
- prompt_tokens_gt: 100000
- tool_calls_estimated_gt: 5
cache: prefix
fallback: openai/gpt-5-5 # if Anthropic 5xxFAQ
Should I use Claude Opus or Sonnet by default?
Sonnet. It is roughly 2x faster, 40% cheaper on input, and within striking distance of Opus on most evals. Reserve Opus for the hardest 10-20% of requests, and multi-step planning, novel coding problems, complex reasoning.
When is Opus actually worth the price?
When the marginal quality gain pays for the latency and cost. Typical wins: planning a multi-day project, refactoring a complex codebase, debugging a non-trivial system, or generating production-grade content where one extra revision saves a human hour.
What is the context window difference?
Sonnet 4 supports 1M tokens; Opus 4.7 supports 500K. Counter-intuitive but useful. for long-context RAG (whole codebases, multi-document research), Sonnet is the right pick despite being the "smaller" model.
Should I route between them?
Yes. The standard pattern: Sonnet handles every request by default, and a router promotes to Opus only when the task complexity or required answer length crosses a threshold. An AI gateway makes this one config block.
Are they on the same release cadence?
Roughly. Anthropic ships Opus → Sonnet → Haiku updates together each generation. Pricing has held steady through the 4.x cycle.
Route between Opus and Sonnet automatically
Swfte ships the policy primitive. default to Sonnet, promote to Opus on a complexity trigger, fall back if Anthropic 5xx. One config block.
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