Claude Opus 5 vs Claude Sonnet 5: what the multiplier costs you
Same vendor, same API, two price tiers. This is the decision most Claude API users actually face: pay the frontier rate on everything, or route work by difficulty. The gap in the table below is what that decision is worth — and because both sit behind the same endpoint and the same key, it is the cheapest tiering decision on the site to implement: a model-ID change per request, not a new integration.
Claude Opus 5 vs Claude Sonnet 5: the numbers side by side
| Claude Opus 5 | Claude Sonnet 5 | |
|---|---|---|
| Gateway rate — input | $2.5 | $1 |
| Gateway rate — output | $12.5 | $5 |
| Official list — input | $5 | $2 |
| Official list — output | $25 | $10 |
| Blended at 1/3 output | $5.83 | $2.33 |
| Output : input price ratio | 5.0× | 5.0× |
USD per 1M tokens. Gateway rates checked 2026-09-16; official list prices as published by each vendor. Gateway rates move with upstream promotions — re-check before committing a budget.
What each costs per month
| Monthly tokens | Claude Opus 5 | Claude Sonnet 5 | Cheaper |
|---|---|---|---|
| 10M | $58.33 | $23.33 | Claude Sonnet 5 — 60% less |
| 100M | $583 | $233 | Claude Sonnet 5 — 60% less |
| 1000M | $5,833 | $2,333 | Claude Sonnet 5 — 60% less |
Assumes 1/3 of tokens are output and 2/3 input — roughly a chat or coding-agent mix. At a 100M tokens/month workload the gap is $350 a month, or $4,200 a year. Change the split in the calculator — output-heavy workloads widen the gap.
How much tokens each budget buys
| Budget | Claude Opus 5 | Claude Sonnet 5 | Extra tokens |
|---|---|---|---|
| $100 | 17M | 43M | Claude Sonnet 5 — 26M more |
| $1,000 | 171M | 429M | Claude Sonnet 5 — 257M more |
Tokens purchasable at the blended rate above. Output tokens cost more than input, so reading these figures as "all input" would overstate them.
Which one to pick
The routing pattern beats the model choice here. Three workable arrangements:
- All Sonnet. Simplest, one model to reason about, and the right call if your volume is low enough that the difference does not fund the engineering time to route.
- Sonnet with Opus escalation. Run everything on the cheaper model, detect failures or low confidence, re-run only those on the frontier model. You keep most of the saving and cap the quality risk.
- Opus for planning, Sonnet for execution. Use the dearer model once to produce a plan or a spec, then let the cheaper model carry out the mechanical steps. Common in coding agents, where the expensive part is deciding and the cheap part is typing.
The monthly table above is the budget side of that decision. Whether the quality difference is worth the multiplier is a question for your own eval set — the price index should not answer it for you.
Switching between them
Both models are called through the same endpoint, so this is a model-ID change, not a migration. Setup references: OpenAI & Anthropic SDK · Claude Code · Cursor · reducing API cost.
Related comparisons: Three ways to pay for Claude · Claude vs GPT · What Claude Code costs per month
FAQ
Is Claude Opus 5 or Claude Sonnet 5 cheaper?
At current gateway rates Claude Sonnet 5 is cheaper for a mixed workload — $5.83 versus $2.33 per 1M tokens blended at one third output. The answer depends on your input/output split: output tokens are priced several times higher than input on both models (5x and 5x respectively), so an output-heavy workload widens the gap.
How much does Claude Opus 5 cost per month?
At $5.83 per 1M blended tokens: about $58.33 for 10M tokens a month, $583 for 100M, and $5,833 for 1B. That is pure token spend — there is no subscription on either model.
How much does Claude Sonnet 5 cost per month?
At $2.33 per 1M blended tokens: about $23.33 for 10M tokens a month, $233 for 100M, and $2,333 for 1B.
Can I switch between them without rewriting my code?
Both are reached through the same gateway endpoint, so switching is a model-ID change in the request rather than a new integration. See the SDK guide for the one-line change, or the Claude Code setup if you are switching inside a coding agent.
Should I run everything on the cheaper model?
Only if your eval set says quality holds. The pattern we would suggest testing first is verification rather than blind substitution: run the cheaper model, detect failures, and escalate only those. That usually captures most of the saving while bounding the risk, and it is measurable before you commit.