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Comparison · 2 models · Updated Nov 2, 2026

GPT-5.6 Terra vs GPT-6.1 Terra

GPT-6.1 Terra comes out ahead, 76 to 67 on our weighted score, and it is the cheaper option too.

  1. OpenAI

    GPT-5.6 Terra

    Released Jul 9, 2026

    67/100
    • ECI160.1
    • Price$2.00 / $12.00
    • Context1.05M
    Full specs Remove GPT-5.6 Terra
  2. Our pick

    OpenAI

    GPT-6.1 Terra

    Released Oct 26, 2026New

    76/100
    • ECI168.1
    • Price$1.00 / $5.00
    • Context1.05M
    Full specs Remove GPT-6.1 Terra

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

GPT-6.1 Terra is our pick

GPT-6.1 Terra is the better all-round choice, scoring 76/100 against GPT-5.6 Terra (67). It leads on capability and price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGPT-6.1 TerraCapabilities Index (ECI): GPT-6.1 Terra 168.1 · GPT-5.6 Terra 160.1
  • Lowest priceGPT-6.1 TerraGPT-6.1 Terra $2.00 · GPT-5.6 Terra $4.50 per 1M tokens (3:1 blend)
  • Longest contextAbout the sameGPT-5.6 Terra 1,050,000 · GPT-6.1 Terra 1,050,000 tokens
  • Widest inputsSame inputsGPT-5.6 Terra: Text, Images, PDFs · GPT-6.1 Terra: Text, Images, PDFs
  • Self-hostingNo open weightsBoth are available only through APIs
How the score is built
MeasureWeightGPT-5.6 TerraGPT-6.1 Terra
CapabilityCapabilities Index (ECI)50%8999
Price25%1834
Inputs & features15%8080
Context window10%6161
Overall100%67/10076/100
02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

GPT-5.6 Terra vs GPT-6.1 Terra specifications side by side
SpecificationGPT-5.6 TerraOpenAIGPT-6.1 TerraOpenAI
Capability
Capabilities Index (ECI)160.1168.1 (best)
ECI rank#15 of 165#3 of 165 (best)
GPQA DiamondGraduate-level science questions93.3%94.3% (best)
FrontierMath Tiers 1–3Research-level mathematics86.0%90.9% (best)
OTIS Mock AIME 2024–2025Competition mathematics99.7%100% (best)
SimpleQA VerifiedShort factual questions43.2%57.3% (best)
Price per million tokens
Input$2.00$1.00 (best)
Output$12.00$5.00 (best)
Cached input$0.20$0.05 (best)
Blended (3:1)$4.50$2.00 (best)
Long-context rateOver 272K: $4.00 / $18.00Over 272K: $2.00 / $7.50
Price sourceOfficial OpenAI APIOfficial OpenAI API
Limits
Context window1,050,000 tokens1,050,000 tokens
Max output128,000 tokens128,000 tokens
Inputs and features
TextYesYes
ImagesYesYes
PDFsYesYes
AudioNoNo
VideoNoNo
ReasoningYeslow · medium · high · xhigh · maxYeslow · medium · high · xhigh · max
Tool callingYesYes
Structured outputYesYes
Availability
WeightsProprietaryProprietary
API model IDgpt-5.6-terragpt-6.1-terra
API providers45 (best)22
ReleasedJul 9, 2026Oct 26, 2026
Knowledge cutoffFeb 16, 2026Jun 1, 2026
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • GPT-5.6 Terra$44.00
  • GPT-6.1 Terra$20.00
04 — Questions

Which should you choose?

Which is better: GPT-5.6 Terra or GPT-6.1 Terra?

GPT-6.1 Terra is the better all-round choice, scoring 76/100 against GPT-5.6 Terra (67). It leads on capability and price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT-5.6 Terra or GPT-6.1 Terra?

GPT-6.1 Terra is cheaper at $1.00 input / $5.00 output per million tokens (official OpenAI API price). GPT-5.6 Terra costs $2.00 input / $12.00 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $2.00 per million tokens for GPT-6.1 Terra versus $4.50 for GPT-5.6 Terra (2.3× as much).

Which scores higher on benchmarks?

GPT-6.1 Terra scores higher on the Capabilities Index (ECI): GPT-6.1 Terra 168.1 (#3 of 165) and GPT-5.6 Terra 160.1 (#15 of 165). Their confidence ranges do not overlap (164.9–172.9 vs 157.8–163.4), so the gap is a real one. On individual benchmarks: GPQA Diamond — GPT-6.1 Terra 94.3%, GPT-5.6 Terra 93.3%; FrontierMath Tiers 1–3 — GPT-6.1 Terra 90.9%, GPT-5.6 Terra 86.0%; OTIS Mock AIME 2024–2025 — GPT-6.1 Terra 100%, GPT-5.6 Terra 99.7%; SimpleQA Verified — GPT-6.1 Terra 57.3%, GPT-5.6 Terra 43.2%.

Which is better for coding?

There are no published SWE-bench Verified results for GPT-5.6 Terra and GPT-6.1 Terra yet, so there is no like-for-like coding score. On overall capability, GPT-6.1 Terra leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.

Which has the bigger context window?

GPT-5.6 Terra and GPT-6.1 Terra share the same 1,050,000-token context window. Maximum output per response: GPT-5.6 Terra up to 128,000, GPT-6.1 Terra up to 128,000 tokens.

Which can read images, PDFs, audio or video?

GPT-5.6 Terra accepts text, images and PDFs; GPT-6.1 Terra accepts text, images and PDFs. They handle the same number of input types.

Are any of these open source?

No. GPT-5.6 Terra and GPT-6.1 Terra are proprietary and only available through APIs and apps.

Which is newer?

GPT-6.1 Terra is the newest, released Oct 26, 2026. GPT-5.6 Terra came out Jul 9, 2026. Knowledge cutoff: GPT-5.6 Terra Feb 16, 2026, GPT-6.1 Terra Jun 1, 2026.

How do you decide the winner?

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.

05 — Keep comparing

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