# Claude 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).

## Specifications

| | Claude Opus 4.8 | Claude Sonnet 5 |
| --- | --- | --- |
| Lab | Anthropic | Anthropic |
| Access | API only | API only |
| Context window | 200K tokens | 1M tokens |
| List price, input | $5 / M tokens | $3 / M tokens |
| List price, output | $25 / M tokens | $15 / M tokens |
| Cached input | n/a | n/a |
| License | Proprietary API | Proprietary API |
| Fine-tunable | No | No |

Specifications 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.

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[HTML page](https://allocate.network/compare/opus-4-8-vs-sonnet-5) · [Claude Opus 4.8](https://allocate.network/models/opus-4-8.md) · [Claude Sonnet 5](https://allocate.network/models/sonnet-5.md) · [Machine-readable catalog](https://allocate.network/catalog.json)