Claude Sonnet 4.6 vs GPT-5.6 Terra
Anthropic against OpenAI, costed on the same three workloads. GPT-5.6 Terra is cheaper on all three workloads.
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Monthly bill, side by side
| Workload | Claude Sonnet 4.6 | GPT-5.6 Terra | Difference |
|---|---|---|---|
| Support chatbot 2,500 six-turn conversations a day |
$12,083 | $8,865 | $3,218 (+36%) |
| Document summarizer 1,000 single-shot summaries a day |
$1,458 | $1,020 | $438 (+43%) |
| Coding agent 200 twelve-turn sessions a day |
$8,424 | $5,976 | $2,448 (+41%) |
No prompt caching and no batch discount on either side, so the comparison is like for like. Both figures assume 30 days a month.
The rate cards
| Claude Sonnet 4.6 | GPT-5.6 Terra | |
|---|---|---|
| Input, per 1M tokens | $3 | $2 |
| Output, per 1M tokens | $15 | $12 |
| Cached input | $0.3 | $0.2 |
| Context window | 1M | 922K |
| Maximum output | 128K | 128K |
| Reasoning model | yes | yes |
| Vision | yes | yes |
Beyond the price
- Claude Sonnet 4.6 reads up to 1M tokens of context in one request; GPT-5.6 Terra stops at 922K.
- Only GPT-5.6 Terra offers a batch discount — 50% off both rates for work that can wait.
Run this comparison on your own numbers
Full detail: Claude Sonnet 4.6 pricing · GPT-5.6 Terra pricing
More comparisons
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- GPT-5.6 Terra vs Claude Opus 4.6
- GPT-5.6 Terra vs Claude Opus 4.7
- GPT-5.6 Terra vs Claude Opus 4.8
Common questions
Which is cheaper, Claude Sonnet 4.6 or GPT-5.6 Terra?
GPT-5.6 Terra is cheaper on all three workloads.
How much would Claude Sonnet 4.6 and GPT-5.6 Terra cost each month?
On PromptSpend's standard workloads, per month: support chatbot: Claude Sonnet 4.6 $12,083, GPT-5.6 Terra $8,865 (GPT-5.6 Terra is cheaper by $3,218); document summarizer: Claude Sonnet 4.6 $1,458, GPT-5.6 Terra $1,020 (GPT-5.6 Terra is cheaper by $438); coding agent: Claude Sonnet 4.6 $8,424, GPT-5.6 Terra $5,976 (GPT-5.6 Terra is cheaper by $2,448). No prompt caching and no batch discount is assumed.
How do Claude Sonnet 4.6 and GPT-5.6 Terra differ apart from price?
Claude Sonnet 4.6 reads up to 1M tokens of context in one request; GPT-5.6 Terra stops at 922K. Only GPT-5.6 Terra offers a batch discount — 50% off both rates for work that can wait.