Claude Opus vs Sonnet: which model to use
Opus and Sonnet solve different problems. Choosing well is the easiest way to get better results and spend fewer tokens — and you can keep both on one key.
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Use Sonnet by default
Sonnet 5 and Sonnet 4.6 handle the vast majority of coding and agent work quickly and cost-effectively. Start here.
See also: Claude Opus 4.8 through the API
Escalate to Opus for hard problems
Reach for Opus 4.8 on complex refactors, architecture, and long high-stakes sessions where extra reasoning pays for itself.
Because one key covers both, you can route each task to the right tier without juggling providers.
| Claude Opus 4.8 | Claude Sonnet 5 | |
|---|---|---|
| Official price (in / out per 1M) | $5 / $25 | $3 / $15 |
| Here from −60% | $2 / $10 | $1.20 / $6 |
| Context window | 1M tokens | 1M tokens |
| Best for | Hard reasoning, long agent runs | Everyday coding and agents |
Frequently asked questions
Which is better for coding?
Sonnet is the recommended default for daily coding; use Opus for complex reasoning and long refactors.
Can I use both on one account?
Yes. Opus, Sonnet and Haiku all share the same key and prepaid balance.
Start with Google or GitHub and get $10 of Claude usage at official prices — no card required.