GPT-5.5 Instant vs GPT-6.1 Terra
GPT-6.1 Terra leads the LLM Stats Score 47.5 to 31.7. GPT-6.1 Terra is 5.6x cheaper per token.
OpenAI · OpenAI · Updated for 2026
Which is better?
GPT-6.1 Terra leads the overall LLM Stats Score 47.5 to 31.7, ranking #36 overall.
In the 4 individual benchmarks reported for both models, GPT-6.1 Terra wins 4; this is a narrower head-to-head signal than the composite indexes.
On price, GPT-6.1 Terra is roughly 5.6x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-6.1 Terra also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose GPT-5.5 Instant
- you want predictable pricing at $5.00/M input and $30.00/M output
Choose GPT-6.1 Terra
- overall performance matters — it scores 47.5 and ranks #36 on LLM Stats
- your work emphasizes reasoning — it leads those capability indexes
- you value its reported benchmark strengths — it wins 4 of 4 exact shared results
- cost matters — it's about 5.6x cheaper per token
- you process long inputs — it offers a 1,050,000 token context window
- you want the most recent training data — it shipped Oct 2026
At a glance
The differences that matter most.
Individual benchmarks
9 reported for GPT-5.5 Instant · 8 for GPT-6.1 Terra
GPT-5.5 Instant outperforms in 0 benchmarks, while GPT-6.1 Terra is better at 4 benchmarks (HealthBench, HealthBench Consensus, HealthBench Hard, HealthBench Professional).
GPT-6.1 Terra significantly outperforms across most benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5.5 Instant ($5.00/1M tokens) is 5.0x more expensive than GPT-6.1 Terra ($1.00/1M tokens).
For output processing, GPT-5.5 Instant ($30.00/1M tokens) is 6.0x more expensive than GPT-6.1 Terra ($5.00/1M tokens).
In conclusion, GPT-5.5 Instant is more expensive than GPT-6.1 Terra.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-6.1 Terra accepts 1,050,000 input tokens compared to GPT-5.5 Instant's 400,000 tokens. Both models can generate responses up to 128,000 tokens.
Input capabilities
Documented input modalities across available providers
Both GPT-5.5 Instant and GPT-6.1 Terra support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5.5 Instant
GPT-6.1 Terra
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
GPT-5.5 Instant was released on 2026-05-05, while GPT-6.1 Terra was released on 2026-10-26.
GPT-6.1 Terra is 6 months newer than GPT-5.5 Instant.
May 5, 2026
5 months ago
Oct 26, 2026
3 days ago
5mo newerKnowledge Cutoff
When training data ends
GPT-5.5 Instant has a knowledge cutoff of 2025-08-31, while GPT-6.1 Terra has a cutoff of 2026-06-01.
GPT-6.1 Terra has more recent training data (up to 2026-06-01), making it potentially better informed about events through that date compared to GPT-5.5 Instant (2025-08-31).
Aug 2025
Jun 2026
10 mo newerProvider Availability
GPT-5.5 Instant is available from OpenAI. GPT-6.1 Terra is available from OpenAI.
GPT-5.5 Instant
GPT-6.1 Terra
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-5.5 Instant and GPT-6.1 Terra side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-5.5 Instant vs GPT-6.1 Terra.