GPT-5.6 Terra API Pricing
OpenAI · context window 1.1M · prices updated 2026-09-15
Where GPT-5.6 Terra sits on price
At $12.00 per million output tokens, GPT-5.6 Terra is a premium tier model — 5.8× the median output price of $2.08, which puts it cheaper than 18% and pricier than 82% of the models we track. It sits 64th cheapest of the 92 OpenAI models we track. Output costs 6.0× more than input here, so anything that makes the model write less — tighter instructions, structured output, lower max_tokens — moves the bill more than trimming the prompt.
Cached input is 90% cheaper. On an input-heavy workload you need roughly a 28% cache-hit rate to take 25% off the input line — reachable for chatbots and agents that resend the same system prompt and history.
What real workloads cost on GPT-5.6 Terra
These three workloads are the ones teams actually run on a premium-priced model — a $12.00/1M model is not bought for the same job as one ten times the price.
| Workload | Per request | Per month |
|---|---|---|
| Support chatbot — 500 conversations/day (5K in / 1.4K out) Conversation history re-sent each turn — the classic prompt-caching win. | $0.0268 | $402 |
| Coding agent — 300 sessions/day (60K in / 12K out) Multi-step loops re-read the same files; caching matters more than raw price. | $0.264 | $2376 |
| Long-context analysis — 200 runs/day (250K in / 4K out) Only possible on large-context models; input cost is nearly the whole bill. | $0.548 | $3288 |
Model your exact traffic in the API cost calculator — it preloads GPT-5.6 Terra with caching and batch options.
GPT-5.6 Terra price history
OpenAI last raised GPT-5.6 Terra's output price on Aug 21, 2026 (+100% per output token), from $1.00/$6.00 to $2.00/$12.00 per 1M in/out. That is the only repricing in the 44 days we have tracked it — worth knowing before you hard-code today's rate into a budget.
| Date | Input /1M | Output /1M | Output change |
|---|---|---|---|
| Aug 2, 2026 (tracking began) | $1.00 | $6.00 | — |
| Aug 21, 2026 | $2.00 | $12.00 | +100% |
Change-points from our daily price snapshots (tracking since Aug 2, 2026; intraday moves between snapshots are not captured).
GPT-5.6 Terra vs Gemini 3.1 Pro Preview Custom Tools
The closest-priced alternative from another vendor is Gemini 3.1 Pro Preview Custom Tools (Google) — priced within a rounding error on output, with identical input pricing. When two models land this close on price, the decision is quality on your own workload, not the price sheet: run 50 real requests through both and compare.
See Gemini 3.1 Pro Preview Custom Tools pricing →Cheaper alternatives
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Frequently asked questions
› How much does the GPT-5.6 Terra API cost?
GPT-5.6 Terra costs $2.00 per million input tokens and $12.00 per million output tokens, with cached input at $0.2 per million (90% cheaper). That works out to roughly 83,333 output tokens per dollar.
› What does the support chatbot workload cost on GPT-5.6 Terra?
Support chatbot — 500 conversations/day (5K in / 1.4K out) costs about $0.0268 per request and $402 per month on GPT-5.6 Terra. Conversation history re-sent each turn — the classic prompt-caching win.
› What does it cost to fill GPT-5.6 Terra's 1.1M context window?
Sending 1.1M of input in a single request costs $2.10 at $2.00 per million tokens — before any output. With prompt caching that same fill drops to about $0.21 on repeat requests. This is why large context windows are cheap to advertise and expensive to actually use.
› Is GPT-5.6 Terra worth the price?
GPT-5.6 Terra sits in the middle of the market (64 of 92 by price within OpenAI). The honest test is a routing experiment: send the same 200 real requests to this model and to a tier below, and compare failure rate against the price gap — most teams find a majority of traffic never needed the pricier model.