Prices → Compare → GPT-5.6 Terra vs Claude Sonnet 5
GPT-5.6 Terra vs Claude Sonnet 5: API cost compared
GPT-5.6 Terra lists at $1.000 in / $6.000 out per 1M tokens. Claude Sonnet 5 lists at $2.000 in / $10.00. Sticker price only tells you so much — below is what each actually costs across eight production workloads.
Side by side
| GPT-5.6 Terra | Claude Sonnet 5 | |
|---|---|---|
| Provider | OpenAI | Anthropic |
| Input per 1M | $1.000 | $2.000 |
| Output per 1M | $6.000 | $10.00 |
| Cached input per 1M | $0.100 | $0.200 |
| Context window | 400k | 200k |
| Blended per 1M (3:1) | $2.250 | $4.000 |
Monthly cost by workload
Caching applied at each workload's typical hit rate. This is where the two models actually separate.
| Workload | GPT-5.6 Terra | Claude Sonnet 5 | Cheaper | Difference |
|---|---|---|---|---|
| Customer support chatbot | $146.40 | $257.80 | GPT-5.6 Terra | $111.40 (43%) |
| RAG document Q&A | $196.00 | $368.00 | GPT-5.6 Terra | $172.00 (47%) |
| Coding agent | $104.50 | $185.00 | GPT-5.6 Terra | $80.50 (44%) |
| Bulk summarization | $1,386 | $2,692 | GPT-5.6 Terra | $1,306 (49%) |
| Structured data extraction | $1,870 | $3,490 | GPT-5.6 Terra | $1,620 (46%) |
| Long-form content generation | $254.60 | $429.20 | GPT-5.6 Terra | $174.60 (41%) |
| Email triage agent | $432.50 | $805.00 | GPT-5.6 Terra | $372.50 (46%) |
| Translation pipeline | $1,645 | $2,810 | GPT-5.6 Terra | $1,165 (41%) |
How to read this
GPT-5.6 Terra is cheaper on the majority of these workloads, but "majority" is not the decision. The output:input price ratio is 6.0 for GPT-5.6 Terra and 5.0 for Claude Sonnet 5. If your traffic is output-heavy — long-form drafting, translation — the model with the lower output price wins regardless of what the input price suggests. If you are input-heavy — RAG, bulk summarization, agents re-reading a codebase — the cached input rate matters more than either headline number.
Cost is also not the only axis. This site does not benchmark quality, latency, or rate limits, and a model that is 3x cheaper but needs two attempts per task is not cheaper. Use these numbers to size a bill, then validate on your own evals.
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| Model | In /1M | Out /1M | Monthly | vs best |
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