Sonnet 5 reaches what used to be Opus-tier quality on a lot of coding and agentic work, at $3 per million input tokens against Opus 5's $5. For most teams this is the routing decision that actually moves the budget — not which vendor, but which tier handles which task.
Claude Opus 5 vs Claude Sonnet 5 at a glance
| Claude Opus 5 | Claude Sonnet 5 | |
|---|---|---|
| Price (per 1M tokens) | $5 in / $25 out | $3 in / $15 out |
| Context window | 1M tokens | 1M tokens |
| Max output | 128K tokens | 128K tokens |
| Positioning | Deep reasoning, long-horizon agentic work | Best speed-to-intelligence balance |
| Thinking default | On (adaptive) | On (adaptive) |
| Effort ladder | low → max | low → max |
| Fast mode | Yes | No |
| Best for | The hard 20% of your workload | The routine 80% |
Choose Claude Opus 5 if
- Unfamiliar codebases, gnarly debugging, and multi-file features where a wrong answer is expensive.
- Long autonomous runs where coherence over hours matters more than cost per turn.
- Work where correctness carries commercial weight — a model you can escalate to.
Choose Claude Sonnet 5 if
- High-volume production traffic: chat, classification, routine drafting, well-patterned code.
- Latency-sensitive interactive features.
- Anything where you would happily accept 95% of the quality for 60% of the price.
The verdict
Do not pick one. Route: Sonnet 5 as the default, Opus 5 as the escalation tier. That structure beats either model used alone on both cost and quality.
Whichever way you lean, run the decision on your own workload rather than a benchmark table. Twenty representative tasks from your real queue will tell you more than any published score.
More on Claude Opus 5
Start with the complete Claude Opus 5 guide for the overview, or go deeper:
Ready to go deeper?
Read the full Claude Opus 5 guideFrequently Asked Questions
Is Claude Opus 5 significantly better than Sonnet 5?
On hard work, yes — deep reasoning, unfamiliar codebases, long autonomous runs. On routine work the gap narrows sharply, which is exactly why routing beats picking. Sonnet 5 reaches near-Opus quality on much of the coding and agentic workload at $3/$15.
How do I decide which model handles a request?
By task shape, not by user or plan. Route on difficulty signals you can measure — input size, whether tools are involved, how many steps the task needs, and the cost of being wrong. Then escalate to Opus 5 when the cheaper model's answer fails a check.
Does Sonnet 5 have the same 1M context window?
Yes. Both models offer a 1M-token context window and 128K maximum output, so long-document work is not by itself a reason to pay for Opus. The reason to pay for Opus is reasoning depth over that context.
