GPT-5.6 Terra vs GPT-6.1 Terra
As of October 27, 2026, GPT-5.6 Terra costs 100% more per input token than GPT-6.1 Terra ($2.00 vs $1.00 per 1M), and both have a 922K-token context window.
GPT-5.6 Terra vs GPT-6.1 Terra side by side
| GPT-5.6 Terra | GPT-6.1 Terra | |
|---|---|---|
| Input, per 1M tokens | $2.00 | $1.00 |
| Output, per 1M tokens | $12.00 | $5.00 |
| Cache read, per 1M tokens | $0.20 | $0.05 |
| Cache write, per 1M tokens | $2.50 | $1.25 |
| Context window | 922,000 tokens | 922,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Image input | Yes | Yes |
| Tool calling | Yes | Yes |
| Structured output (JSON) | Yes | Yes |
| Prompt caching | Yes | Yes |
| Reasoning | Yes | Yes |
| Providers on LiteLLM | 9 | 4 |
| Price shown is from | OpenAI | OpenAI |
| Added to LiteLLM | July 9, 2026 | October 26, 2026 |
Cheapest provider for each
- GPT-5.6 Terra: OpenAI at $2.00 input and $12.00 output per 1M tokens (
gpt-5.6-terra) - GPT-6.1 Terra: OpenAI at $1.00 input and $5.00 output per 1M tokens (
gpt-6.1-terra)
When to pick which
Pick GPT-5.6 Terra for
- Available from 9 providers through LiteLLM, vs 4.
Pick GPT-6.1 Terra for
- Costs 50% less per input token: $1.00 vs $2.00 per 1M.
From differences in the data above only; where the data is equal, no reason is given.
Call GPT-5.6 Terra or GPT-6.1 Terra with LiteLLM
Both use the OpenAI format through LiteLLM, so switching is a model name change. Set each provider's API key in the environment first.
from litellm import completion
messages = [{"role": "user", "content": "Hello!"}]
# GPT-5.6 Terra
response = completion(model="gpt-5.6-terra", messages=messages)
# GPT-6.1 Terra
response = completion(model="gpt-6.1-terra", messages=messages)
# GPT-5.6 Terra, falling back to GPT-6.1 Terra if the call fails
response = completion(model="gpt-5.6-terra", messages=messages, fallbacks=["gpt-6.1-terra"])FAQ
Which is cheaper, GPT-5.6 Terra or GPT-6.1 Terra?
GPT-6.1 Terra is cheaper at 3 input tokens per output token: $2.00 per 1M tokens blended ($1.00 input, $5.00 output), versus $4.50 ($2.00 and $12.00) for GPT-5.6 Terra, as of October 27, 2026.
Which has the larger context window, GPT-5.6 Terra or GPT-6.1 Terra?
Both have a 922,000-token context window.
Can I switch from GPT-5.6 Terra to GPT-6.1 Terra without changing my code?
Yes. Through LiteLLM both use the OpenAI format, so switching means changing the model name from "gpt-5.6-terra" to "gpt-6.1-terra", or pointing a LiteLLM gateway model alias at the other model. You can also use one as a fallback for the other.