Comparison · prices as of 2026-07-04 · re-verified 2026-08-18
Claude Opus 4.5 vs Claude Sonnet 4.5
On price alone, Claude Sonnet 4.5 (Anthropic) runs about 40% cheaper than Claude Opus 4.5 for a typical chat workload (2K input + 500 output tokens, 1,000 requests/day). Whether that's the right trade depends on the capability gap — the breakdown below shows where each one wins.
Price per million tokens
| Spec | Claude Opus 4.5 | Claude Sonnet 4.5 |
|---|---|---|
| Input / MTok | $5 | $3 |
| Output / MTok | $25 | $15 |
| Context window | 200K | 200K |
| Max output | 64K | 64K |
| Class | frontier | workhorse |
Estimated monthly cost by workload
Same models, three realistic usage levels. The gap between them scales with volume, so the right pick can change as you grow.
| Workload | Claude Opus 4.5 | Claude Sonnet 4.5 | Cheaper |
|---|---|---|---|
| Light — chatbot 0.5K in / 0.2K out · 200 req/day | $45.00 | $27.00 | Claude Sonnet 4.5 |
| Typical — assistant 2K in / 0.5K out · 1K req/day | $675 | $405 | Claude Sonnet 4.5 |
| Heavy — RAG / agent 8K in / 2K out · 5K req/day | $13,500 | $8,100 | Claude Sonnet 4.5 |
Which should you pick?
- Cheapest overall: Claude Sonnet 4.5 — about 40% less per month on a typical assistant workload.
- Claude Sonnet 4.5 is cheaper on both input and output, so it stays cheaper whether your workload is prompt-heavy or generation-heavy.
- Different classes: Claude Opus 4.5 is a frontier model, Claude Sonnet 4.5 is a workhorse model — expect Claude Opus 4.5 to be stronger on hard reasoning and Claude Sonnet 4.5 to be faster and cheaper to run.
Frequently asked questions
Is Claude Opus 4.5 or Claude Sonnet 4.5 cheaper?
Claude Sonnet 4.5 is cheaper — roughly 40% less per month on a typical assistant workload (2K input + 500 output tokens, 1,000 requests/day).
What do Claude Opus 4.5 and Claude Sonnet 4.5 cost per million tokens?
Claude Opus 4.5 is $5 per million input tokens and $25 per million output. Claude Sonnet 4.5 is $3 input and $15 output. Prices are first-party API list rates as of 2026-07-04.
Which has the larger context window, Claude Opus 4.5 or Claude Sonnet 4.5?
Both handle up to 200K tokens of context.
When should I choose Claude Opus 4.5 over Claude Sonnet 4.5?
Choose Claude Opus 4.5 when you need the extra capability of its frontier class; drop to Claude Sonnet 4.5 when speed and cost matter more than peak quality.
Related comparisons
Sources: Anthropic pricing · Anthropic pricing. Run your own numbers in the cost calculator.