Claude Sonnet vs Opus: Which Should You Use?

Compare exact Sonnet and Opus models first

A family name alone does not identify the model you are comparing. The official API has precise model IDs, while developer products may offer aliases. Record the actual model, interface, and reasoning effort so one trial does not use an older model while the other has moved to a new version. Official model overview

Claude Code model selection also depends on account, organization, and client settings. DSH has its own provider catalog and configuration. An official directory listing does not guarantee the model appears in everyone's picker. Claude Code model configuration

Compare upgrade costs on the same basis

Current standard text API input and output rates, in US dollars per million tokens:

These are standard text rates. They do not include every caching, tool, or service condition, and they are not Claude Code subscription prices. Official API pricing

If each model used 10,000 ordinary input tokens and 2,000 output tokens with no additional charges, the examples would cost $0.04 and $0.08. The unit-price difference is clear at equal usage, but completing the same task may consume different amounts.

If you use a subscription, distinguish the session's estimated token cost from usage counted against your plan. Official Claude Code documentation says the session dollar figure is not a subscription user's bill. Check the relevant metering page for authoritative API costs. Claude Code usage and cost documentation

When is trying Opus worthwhile?

Start with the cost of failure. For a small change with clear tests and straightforward review, you can start with your current lower-cost setup if it fits the task. Changes involving cross-module dependencies, hidden failures, or costly review give more reason to run an upgrade trial.

For example, a field-mapping change may have a direct input-to-output check. A concurrency change may require state-transition and boundary checks in addition to unit tests. Both are coding tasks, but that does not give them the same selection criteria.

The official cost-optimization guide also discusses models, reasoning effort, and task cost. Its recommendations come with methods and evaluation conditions; they do not establish a universal starting model for every task. Official optimization guide

Run a comparison whose result you can explain

Choose a task with clear acceptance checks. Begin from the same code state, provide the same requirements, keep tool permissions consistent, and record each model's reasoning effort and budget.

Use a small record:

One result can help you decide whether to keep testing that type of task. It cannot establish a universal model ranking. Different tasks need fresh checks.

Fix configuration problems before switching models

If tools cannot read the project, permissions are wrong, or the request lacks necessary material, a more expensive model does not directly fix those problems. Check what it received, which tools ran, and whether results returned correctly.

In DSH, use the Claude provider guide to confirm credentials and routing before a controlled task. An API key and product-subscription sign-in are not the same setting.

Existing articles can also supply context. TokenMix's April 2026 comparison concerns Sonnet 4.6 and Opus 4.7. Its rates and traffic recommendations belong to that version context. Its distinction between token prices and the cost of completing a task is useful. The old conclusions do not transfer simply by replacing the model names with 5.5. Historical selection article

Common questions

Which tasks are worth comparing with Opus?

Tasks with cross-module dependencies, hidden failures, or costly review are reasonable candidates for an Opus upgrade trial. Record whether it reduces failures and manual checking before deciding whether the extra spend is worthwhile.

How should I compare Sonnet and Opus task costs?

Total the charges for all requests, failed retries, and tools for each model. Record human review and correction time separately. Use the same acceptance checks for both models. Calculate spend from the rate table, then use your task records to assess rework.

What should I check in an online evaluation?

Check the exact model, test set, tool permissions, reasoning settings, and acceptance criteria. Use results with comparable conditions as a reference, then verify them on your own codebase. Official positioning and third-party examples cannot replace that check.

Make the upgrade a decision you can verify

To choose between Claude Sonnet and Opus, pin the exact models and how you pay for access, then compare the same task. If spending more reduces failures and review effort, it may be worthwhile for that type of task. Without those records, keep it as a candidate rather than a permanent default for every project.

Use the coding-repair test template to start a comparison. For retries and review costs, continue with the agent task-cost article.

Model setup, selection and cost guides