The Claude 3 Family Positioning
Anthropic's Claude 3 family (released March 2024) ships in three tiers:
- Haiku — $0.25/1M input, fastest, for simple classification and extraction
- Sonnet — $3/1M input, balanced quality and cost, the default for most tasks
- Opus — $15/1M input, highest capability, for complex multi-step reasoning
The pricing ratio is roughly 1:12:60. The question is never "is Opus better?" — it usually is — but "does the quality difference justify 5x the cost of Sonnet for this specific task?"
Where Opus Outperforms Sonnet
Complex multi-step reasoning: Opus scores 50.4% on GPQA (Graduate-Level Google-Proof Q&A) versus Sonnet's 40.4%. This 10-point gap represents real performance differences on tasks like:
- Analyzing a legal contract and identifying specific risk clauses
- Multi-step scientific literature synthesis with correct attribution
- Complex business strategy analysis that requires holding many constraints simultaneously
Nuanced long-form writing: For tasks like writing a 5,000-word technical report that requires consistent voice, coherent argument structure, and domain accuracy throughout, Opus produces noticeably fewer internal contradictions and logical gaps.
Advanced mathematics: On the MATH benchmark (competition mathematics), Opus scores 60.1% vs Sonnet's 58.7% — a smaller gap than GPQA, meaning for standard math tasks Sonnet is sufficient.
Complex coding with subtle bugs: On problems from SWE-Bench (real GitHub issues), Opus's gap over Sonnet is meaningful for hard instances.
When NOT to Use Opus
- Simple extraction (parse this JSON, extract dates from this text) — Haiku handles this
- Summarization of a single document — Sonnet is sufficient
- FAQ answering where the answer is in the provided context — Haiku
- Translation — Sonnet matches Opus on most language pairs
- Code generation for standard CRUD tasks — Sonnet is sufficient
A rough rule: if the task would get a 100% correct answer from a smart undergraduate with unlimited time to think, Sonnet will handle it. Reserve Opus for tasks where even a smart human would struggle.
Batch API for 50% Cost Reduction
Anthropic's batch API allows you to submit large numbers of requests and receive results within 24 hours at half the standard price:
import anthropic
client = anthropic.Anthropic()
# Submit a batch of 100 complex analysis requests
batch = client.beta.messages.batches.create(
requests=[
{
"custom_id": f"analysis-{i}",
"params": {
"model": "claude-opus-4-5",
"max_tokens": 2048,
"messages": [
{"role": "user", "content": f"Analyze contract clause: {contract_clauses[i]}"}
],
},
}
for i in range(100)
]
)
print(f"Batch ID: {batch.id}")
At 50% off, Opus batch pricing becomes $7.50/1M input — still 2.5x Sonnet's standard rate, but much more tractable for high-volume non-latency-sensitive workloads like nightly document processing pipelines.
Practical Decision Framework
Is the task latency-sensitive (user waiting in real time)?
YES → Use Sonnet (Opus adds ~50% more latency)
NO → Consider batch API
Does the task require PhD-level domain reasoning?
YES → Opus
NO → Sonnet
Are you processing more than 10k requests/day?
YES → Build routing logic: use Haiku for simple tasks, Sonnet for medium, Opus only for flagged hard cases
NO → Sonnet as default, Opus for known hard cases
