Claude Opus 4 vs Claude Sonnet 4.6: Which AI Model Should You Choose?
Pricing, context windows, latency, capabilities, and a one-line code switch — everything you need to pick the right model.
Choose Claude Sonnet 4.6 for cost-sensitive workloads — it is roughly 50000.0× cheaper on input tokens. Choose Claude Opus 4 when you need its broader capabilities or stronger benchmarks.
These models serve different use cases (Text & Chat vs Multimodal) — pick the one whose category matches your workload.
Side-by-side specs
| Spec | Claude Opus 4 | Claude Sonnet 4.6 |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Category | Text & Chat | Multimodal |
| Input cost / 1M tokens | €150.00 | €0.0030 |
| Output cost / 1M tokens | €750.00 | €0.015 |
| Context window | 200K tokens | 200K tokens |
| Max output tokens | 32,000 | 64,000 |
| Avg. latency | 5.0s | — |
| Featured | Yes | Yes |
| New | Yes | Yes |
| Capabilities | — | text image |
Pricing example
A typical chat workload of 100,000 input tokens plus 50,000 output tokens.
100K in × €150.00 + 50K out × €750.00
100K in × €0.0030 + 50K out × €0.015
For this workload, Claude Sonnet 4.6 is cheaper than Claude Opus 4 by €52.4990 per request.
Switch in one line
Both models live behind Railwail's OpenAI-compatible endpoint. Replace the model string and you are done.
import OpenAI from "openai";
const client = new OpenAI({
apiKey: process.env.RAILWAIL_API_KEY,
baseURL: "https://railwail.com/v1",
});
// Before — using Claude Opus 4
let r = await client.chat.completions.create({
model: "claude-opus-4-20250514",
messages: [{ role: "user", content: "Hello" }],
});
// After — switched to Claude Sonnet 4.6
r = await client.chat.completions.create({
model: "claude-sonnet-4-6-20260217",
messages: [{ role: "user", content: "Hello" }],
});from openai import OpenAI
client = OpenAI(
api_key=os.environ["RAILWAIL_API_KEY"],
base_url="https://railwail.com/v1",
)
# Before — using Claude Opus 4
r = client.chat.completions.create(
model="claude-opus-4-20250514",
messages=[{"role": "user", "content": "Hello"}],
)
# After — switched to Claude Sonnet 4.6
r = client.chat.completions.create(
model="claude-sonnet-4-6-20260217",
messages=[{"role": "user", "content": "Hello"}],
)# Before — using Claude Opus 4
curl https://railwail.com/v1/chat/completions \
-H "Authorization: Bearer $RAILWAIL_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "claude-opus-4-20250514",
"messages": [{"role": "user", "content": "Hello"}]
}'
# After — switched to Claude Sonnet 4.6
curl https://railwail.com/v1/chat/completions \
-H "Authorization: Bearer $RAILWAIL_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "claude-sonnet-4-6-20260217",
"messages": [{"role": "user", "content": "Hello"}]
}'Which one wins for...
Quick verdicts derived from public specs. Always validate on your own workload.
Higher coding category match or larger context wins.
Bigger context window helps maintain long-form coherence.
The larger context window is the deciding factor.
Multimodal/vision support is required for image inputs.
Lower average latency wins for interactive UX.
The model with the lower input-token price wins.
Frequently asked questions
Try Claude Opus 4 and Claude Sonnet 4.6 side by side
One API key, one endpoint, both models. Start free — no credit card required.