AllocateClaude Opus 4.8 vs Claude Sonnet 5
On provider list prices, Claude Sonnet 5 costs $3 per million input tokens against $5 for Claude Opus 4.8: 1.7x apart. Output is $15 against $25 (1.7x).
Claude Opus 4.8 Claude Sonnet 5Specifications and provider list prices from the Allocate catalog, checked 2026-07-21.
What the numbers say
Take 1,000,000 requests a month at 1,200 input and 350 output tokens each. That workload costs $8,850 a month on Claude Sonnet 5 and $14,750 on Claude Opus 4.8 at list: a gap of $5,900, or 1.7x.
Claude Sonnet 5 reads 1M tokens per request against 200K for Claude Opus 4.8, 5.0x the window. That decides which one can take whole documents without splitting them.
Choose Claude Opus 4.8 for
- Hardest reasoning problems
- High-stakes analysis
- Escalation tier for agents
Choose Claude Sonnet 5 for
- Judgment calls with policy context
- Customer-facing writing
- Review and escalation flows
Common questions
Which is cheaper, Claude Opus 4.8 or Claude Sonnet 5?
Claude Sonnet 5, on this workload shape. At list prices it is $3/$15 per million tokens in and out against $5/$25 for Claude Opus 4.8. Billed on Allocate: $3.21/$16.05 against $5.35/$26.75.
Which has the bigger context window?
Claude Sonnet 5: 1,000,000 tokens (1M) against 200,000 (200K) for Claude Opus 4.8.
Can I fine-tune Claude Opus 4.8 or Claude Sonnet 5?
No. Both are closed models served over API. If you want a model you can train and own, start from an open-weights base in the catalog.
Related comparisons
Run the numbers on your workload
Or don’t choose. On Allocate a route name is the contract: point yours at one model today, swap to the other tomorrow, and compare them on your live traffic with per-token metering.