OpenAI: GPT-5.6 Terra Pro API Pricing
OpenAI: GPT-5.6 Terra Pro costs $2.00 per 1M input tokens and $12.00 per 1M output tokens (cache reads: $0.200). Context window: 1.1M. Prices verified 2026-10-21 · source
Alternatives to consider
91% cheaper with nearly identical quality (60 vs 57)
Cheapest openai model — 99% less per month
Where to buy it
Same model, different sellers. First-party vs router pricing, verified independently.
| Channel | Input /1M | Output /1M | vs priciest | Verified |
|---|---|---|---|---|
| OpenAI (direct) | $2 | $12 | baseline | 2026-08-25 |
| OpenRouter | $2 | $12 | baseline | 2026-10-21 |
Rebuilt daily from our snapshot archive — the chart appears once a model has 5+ snapshots of history.
From our own daily snapshot archive — independent of provider announcements.
Intelligence measures reasoning/knowledge/coding benchmarks. A high score with a low blended price = value pick; check the value chart to see where this model lands.
Token economics
| Token type | Price | vs base input |
|---|---|---|
| Standard input | $2.00 | — |
| Cache read | $0.200 | −90% |
| Cache write (5m) | $2.50 | +25% |
| Output | $12.00 | — |
| Web search tool | $10/1k searches | — |
Prompt caching stores repeated context server-side: reads cost far less, but writes carry a one-time premium.
Higher effort = deeper thinking = more reasoning tokens billed as output.
Training data ends here — newer events require retrieval or web search.
What would OpenAI: GPT-5.6 Terra Pro cost you per month?
| Workload | Requests/mo | Avg tokens (in/out) | Est. monthly cost |
|---|---|---|---|
| Light chatbot | 10,000 | 800 / 400 | $64.00 |
| Coding agent | 5,000 | 8,000 / 2,000 | $200.00 |
| RAG pipeline | 30,000 | 4,000 / 500 | $420.00 |
| Doc summarizer | 2,000 | 20,000 / 1,000 | $104.00 |
Estimates use list prices without prompt caching. Caching can cut input cost by up to 90% on repeated context.
About OpenAI: GPT-5.6 Terra Pro
GPT-5.6 Terra Pro is the same underlying model as [GPT-5.6 Terra](https://openrouter.ai/openai/gpt-5.6-terra), served with `reasoning.mode` set to `pro` for higher-quality responses on complex tasks. **Cost note:** pro mode spends far more...
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Frequently asked questions
How much does OpenAI: GPT-5.6 Terra Pro cost?
OpenAI: GPT-5.6 Terra Pro costs $2.00 per 1M input tokens and $12.00 per 1M output tokens; cached input tokens cost $0.200 per 1M. Verified 2026-10-21 — provider source.
What is the context window?
1.1M tokens, with up to 128K output tokens per response. That's roughly 1313 pages of text in a single request.
Does it support prompt caching?
Yes — cached input is $0.200/1M, about 90% cheaper than standard input. Agents and RAG workloads with repeated context benefit most.
What's a cheaper alternative?
ScaleDown: Summarize saves about 99% on a typical workload with comparable quality.
Official resources
- OpenAI: GPT-5.6 Terra Pro on OpenRouter — live endpoint, pricing source of record.
- Artificial Analysis benchmarks → — independent intelligence and performance analysis.
- OpenAI pricing → — first-party pricing and billing details.
- LMArena leaderboard → — independent human-preference rankings.
- Shred your current bill — paste a CSV and see if switching saves money.