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Head-to-head comparison

GPT-4o (2024-08-06) vs GPT-5.6 Terra

GPT-4o (2024-08-06) (OpenAI) and GPT-5.6 Terra (OpenAI) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 18 October 2026

As of 18 October 2026, GPT-5.6 Terra holds the stronger ModelCap Index position (#28 vs #185); GPT-4o (2024-08-06) is 1.2× cheaper per output token ($10.00/1M vs $12.00/1M); and GPT-5.6 Terra offers the longer context window (1M vs 128K tokens).

Which should you choose?

Choose GPT-4o (2024-08-06) if…

  • API cost matters — $10.00/1M output tokens against $12.00/1M, about 1.2× cheaper.

Choose GPT-5.6 Terra if…

  • you want the stronger overall ModelCap Index position — #28 against #185 (75.3 vs 36.8 points).
  • your workload is prompt-heavy — input tokens cost $2.00/1M against $2.50/1M.
  • you need the longer context window — 1M tokens against 128K.
  • you want provider choice — 3 listed API providers against 2.
  • Arena text is your yardstick — 1466 against 1336.
  • Arena coding is your yardstick — 1517 against 1360.
  • you want the more recently listed model — GPT-5.6 Terra was listed 9 July 2026, GPT-4o (2024-08-06) 6 August 2024.

GPT-4o (2024-08-06) vs GPT-5.6 Terra: specs, pricing and context

Specification comparison of GPT-4o (2024-08-06) and GPT-5.6 Terra
FieldGPT-4o (2024-08-06)OpenAIGPT-5.6 TerraOpenAI
ModelCap Index position#185#28
Index score36.875.3
EvidenceMeasuredMeasured
Input price / 1M tokens$2.50$2.00
Output price / 1M tokens$10.00$12.00
Context window128K tokens1M tokens
Declared route output cap16K128K
API providers listed23
Weight accessNo linked weightsNo linked weights
Input modalitiesText, Image, FileFile, Image, Text
First listed6 August 20249 July 2026
PublisherOpenAIOpenAI

Evidence: 2 public benchmark observations across 2 boards · 5 public benchmark observations across 5 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: GPT-4o (2024-08-06) vs GPT-5.6 Terra

Public benchmark boards where GPT-4o (2024-08-06) or GPT-5.6 Terra has a published result
BoardGPT-4o (2024-08-06)GPT-5.6 TerraLeads
Arena textArena (LMArena)13361331–1340Not reported14661462–1471X-HighGPT-5.6 Terra
Arena codingArena (LMArena)13601352–136815171510–1523X-HighGPT-5.6 Terra
LMArena AgentLMArena—0.4%-0.9%–1.7%X-HighOnly one result
ARC-AGI-2ARC Prize Foundation—83.9%MaxOnly one result
ARC-AGI-3ARC Prize Foundation—0.8%MaxOnly one result
AA Intelligence IndexArtificial Analysis—42.1MaxOnly one result
AA Terminal-Bench 2.1Artificial Analysis—88.0%MaxOnly one result
AA τ²-Bench TelecomArtificial Analysis—86.3%MaxOnly one result
AA Humanity's Last ExamArtificial Analysis—42.9%MaxOnly one result
Terminal-Bench 4.0Terminal-Bench (Laude Institute)—21.5%18.3%–24.8%Codex · MaxOnly one result

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

GPT-4o (2024-08-06) vs GPT-5.6 Terra: common questions

Is GPT-4o (2024-08-06) better than GPT-5.6 Terra?

GPT-5.6 Terra ranks higher on the ModelCap Index as of 18 October 2026: #28 against #185. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it. Their published uncertainty intervals do not overlap, but the aggregate Index does not predict performance on every task; compare the relevant benchmark configurations before choosing.

Is GPT-4o (2024-08-06) cheaper than GPT-5.6 Terra?

GPT-4o (2024-08-06) is cheaper on output tokens: $10.00/1M against $12.00/1M. Input tokens are $2.50/1M for GPT-4o (2024-08-06) and $2.00/1M for GPT-5.6 Terra. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens. For 1,000 requests with 2,000 input and 500 output tokens each (2M input + 0.5M output), the listed-rate estimate is $10.00 for GPT-4o (2024-08-06) versus $10.00 for GPT-5.6 Terra. The listed-rate totals are equal. This excludes caching, batch discounts, prompt-length tiers, tool charges and retries; verify the selected endpoint before budgeting.

Which has the bigger context window, GPT-4o (2024-08-06) or GPT-5.6 Terra?

GPT-5.6 Terra has the larger context window: 1M tokens against 128K. OpenRouter catalogue or provider-endpoint declaration. Limits can vary by provider and prompt length; a model-wide maximum has not been independently verified.

Which is better for coding, GPT-4o (2024-08-06) or GPT-5.6 Terra?

Arena coding: GPT-4o (2024-08-06) 1360, GPT-5.6 Terra 1517 — GPT-5.6 Terra leads.

Are GPT-4o (2024-08-06) and GPT-5.6 Terra open-weight models?

GPT-4o (2024-08-06): No linked weights. GPT-5.6 Terra: No linked weights. Open weights mean the checkpoint can be downloaded and self-hosted under its licence. A missing weight link does not identify every API or chat product that offers a model.

Where can I run GPT-4o (2024-08-06) and GPT-5.6 Terra?

ModelCap currently lists 2 API providers for GPT-4o (2024-08-06) and 3 for GPT-5.6 Terra, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this GPT-4o (2024-08-06) vs GPT-5.6 Terra comparison?

Every figure and ModelCap Index position comes from the same published snapshot dated 18 October 2026. Publication and page updates happen separately; use the snapshot date shown on the page.

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