Skip to main content
AI Choice Engine

Model comparison

GPT-5.6 Terra vs Grok 4.5

OpenAI against SpaceXAI, compared on context, price, and attributed benchmark results.

Recorded profile verification October 1, 2026Individual provider fields may changeEvidence confidence: Medium — see receipts below

OpenAI

GPT-5.6 Terra

Balanced

vs

SpaceXAI

Grok 4.5

Balanced

AI model capability comparison
SpecificationGPT-5.6 TerraGrok 4.5
ProviderOpenAISpaceXAI
TierBalancedBalanced
Context windowWinner: 1.05M500K
Max output128KNot verifiedUnverified
Input / 1M tokens$2$2
Output / 1M tokens$12Winner: $6
WeightsClosedClosed
ParametersNot verifiedUnverifiedNot verifiedUnverified
Reasoning levelsnone, low, medium, high, xhigh, maxlow, medium, high
Modalitiestext, imagetext, image
API model idgpt-5.6-terragrok-4.5
ReleasedJuly 9, 2026July 8, 2026
Artificial Analysis Intelligence Index [max] · source date GPT-5.6 Terra: 2026-10-0142Not verifiedUnverified
Terminal-Bench 2.1 · source date GPT-5.6 Terra: 2026-07-0987.4Not verifiedUnverified
Terminal-Bench 2.1 · source date Grok 4.5: 2026-07-16Not verifiedUnverified83.3
LiveBench · source date GPT-5.6 Terra: 2026-09-0577.9Not verifiedUnverified
DeepSWE 1.1 · source date Grok 4.5: 2026-07-16Not verifiedUnverified53
DeepSWE 1.1 · source date Grok 4.5: 2026-07Not verifiedUnverified54

Dates beside benchmark scores refer to the linked source’s publication or capture date unless that source explicitly states when it measured the result. A shared URL alone does not establish comparable runs; unverified setups are marked. Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.

Benchmark receipts

Where each score comes from, and how far it can be compared across models.

Pricing tiers

GPT-5.6 Terra: Launch $2.50/$15, reduced to $2/$12 on July 30. Above 272K input the full request bills $4/$18. Cached input $0.20; cache writes $2.50 at short context. Batch $1/$6 at short context. Regional/FedRAMP processing adds 10% where eligible.

Grok 4.5: Standard $2/$6 per MTok below 200K prompt tokens; at 200K or more the full request bills $4/$12. Cached input $0.30 short or $0.60 long. US regional inference adds 10%. No separate text-output cap is verified.

BalancedRecord checked October 1, 2026

GPT-5.6 Terra

OpenAI’s middle GPT-5.6 tier for balancing intelligence and cost, with text/image input and a 1.05M-token context.

Best for

  • Cost-sensitive production
  • Mixed reasoning workloads
  • High-volume agents

Watch out

GPT-6.1 Sol lists the same $2 input price and a lower $10 output price than Terra’s $12. Compare representative tasks rather than infer quality from token prices or one index. Terra remains listed in the API model catalog.

BalancedRecord checked October 1, 2026

Grok 4.5

Grok 4.5 is SpaceXAI's hosted reasoning model with a 500K-token context and configurable low, medium and high effort.

Best for

  • Real-time data queries
  • Technical tasks
  • Cost-sensitive reasoning

Watch out

An earlier API model, still listed in pricing; current docs recommend Grok 4.7. Context is 500K. xhigh requests map to high and reasoning cannot be disabled; presencePenalty, frequencyPenalty and stop are unsupported. Match the exact model, effort and dated benchmark configuration.

When the cheaper one wins

Grok 4.5 is cheaper on output at $6 per million tokens against $12 for GPT-5.6 Terra — about 2.0×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. On DeepSWE 1.1, Grok 4.5 is 53.8% Pass@1 at $2.42/task versus GPT-5.6 Terra at 69.6% / $4.95/task. This compares standard short-context token rates, not total cost per accepted task. Include input, cache, context tiers, schedules, retries and review in your pilot.

Run the model picker

Evidence confidence: Medium

How strong and complete the evidence behind this comparison is — not a prediction of which model is better.

  • Pricing verified on both sides — Input and output rates are verified for both models.
  • 3/5 core specs verified on both sides — Not published for at least one side: max output, parameter count.
  • No directly aligned benchmark setup — No benchmark has matching cited sources, source dates, units, effort and recorded run details on both models.
  • Verified within the last 90 days — Older of the two catalog checks was 25 days ago.
  • Both models carry source citations — Each side has at least two catalog sources on record.

Source receipts

Each catalog figure was checked against the provider or an independent second source on the date shown.

Related comparisons

Diving deeper on one model? GPT-5.6 Terra · Grok 4.5

Common questions

GPT-5.6 Terra vs Grok 4.5

Answered from the verified figures on this page rather than general guidance.

Is GPT-5.6 Terra or Grok 4.5 cheaper for input?
Both list a base rate of $2 per million input tokens. Actual cost can differ with context tiers, caching, tools and other charges. GPT-5.6 Terra: Launch $2.50/$15, reduced to $2/$12 on July 30. Above 272K input the full request bills $4/$18. Cached input $0.20; cache writes $2.50 at short context. Batch $1/$6 at short context. Regional/FedRAMP processing adds 10% where eligible. Grok 4.5: Standard $2/$6 per MTok below 200K prompt tokens; at 200K or more the full request bills $4/$12. Cached input $0.30 short or $0.60 long. US regional inference adds 10%. No separate text-output cap is verified.
Is GPT-5.6 Terra or Grok 4.5 cheaper for output?
Grok 4.5 is cheaper at $6 per million output tokens, against $12 for GPT-5.6 Terra — roughly 2.0× the price. Estimate both input and output token volume for your workload. These are base rates; GPT-5.6 Terra: Launch $2.50/$15, reduced to $2/$12 on July 30. Above 272K input the full request bills $4/$18. Cached input $0.20; cache writes $2.50 at short context. Batch $1/$6 at short context. Regional/FedRAMP processing adds 10% where eligible. Grok 4.5: Standard $2/$6 per MTok below 200K prompt tokens; at 200K or more the full request bills $4/$12. Cached input $0.30 short or $0.60 long. US regional inference adds 10%. No separate text-output cap is verified.
Which has the larger context window, GPT-5.6 Terra or Grok 4.5?
GPT-5.6 Terra accepts 1.05M tokens against 500K for Grok 4.5. This only matters if you routinely send very long documents or large codebases.
Do GPT-5.6 Terra and Grok 4.5 support the same reasoning levels?
GPT-5.6 Terra exposes none, low, medium, high, xhigh, max, while Grok 4.5 exposes low, medium, high.
Should I use GPT-5.6 Terra or Grok 4.5?
Both are classified in our balanced tier; this editorial grouping does not imply equal capability. GPT-5.6 Terra is a candidate for cost-sensitive production; Grok 4.5 is a candidate for real-time data queries. Compare accuracy, tool reliability, latency and cost on representative tasks.

Next step

Choosing between them

The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.

  • Context: GPT-5.6 Terra takes 1.05M against 500K for Grok 4.5 — only decisive if your prompts approach the smaller window.
Run the model pickerEstimate stack costAll model comparisons

Choosing a harness rather than a model — Cursor, Copilot, Claude Code, Windsurf, or Lovable? Compare agentic harnesses · Latest releases.