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Head-to-head comparison

GPT-5.4 Nano vs GPT-5.6 Terra

GPT-5.4 Nano (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 22 September 2026

As of 22 September 2026, GPT-5.6 Terra holds the stronger ModelCap Index position (#21 vs #81); GPT-5.4 Nano is 9.6× cheaper per output token ($1.25/1M vs $12.00/1M); and GPT-5.6 Terra offers the longer context window (1M vs 400K tokens).

Which should you choose?

Choose GPT-5.4 Nano if…

  • API cost matters — $1.25/1M output tokens against $12.00/1M, about 9.6× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.20/1M against $2.00/1M.

Choose GPT-5.6 Terra if…

  • you want the stronger overall ModelCap Index position — #21 against #81 (79.7 vs 57.3 points).
  • you need the longer context window — 1M tokens against 400K.
  • you want provider choice — 3 listed API providers against 2.
  • Arena coding is your yardstick — 1518 against 1460.
  • ARC-AGI-2 is your yardstick — 83.9% against 5.7%.
  • AA Intelligence Index is your yardstick — 42.1 against 20.7.
  • AA τ²-Bench Telecom is your yardstick — 86.3% against 76.0%.
  • AA Humanity's Last Exam is your yardstick — 42.9% against 28.3%.
  • you want the more recently listed model — GPT-5.6 Terra was listed 9 July 2026, GPT-5.4 Nano 17 March 2026.

GPT-5.4 Nano vs GPT-5.6 Terra: specs, pricing and context

Specification comparison of GPT-5.4 Nano and GPT-5.6 Terra
FieldGPT-5.4 NanoOpenAIGPT-5.6 TerraOpenAI
ModelCap Index position#81#21
Index score57.379.7
EvidenceMeasuredMeasured
Input price / 1M tokens$0.20$2.00
Output price / 1M tokens$1.25$12.00
Context window400K tokens1M tokens
Max output tokens128K128K
API providers listed23
Weight accessAPI onlyAPI only
Input modalitiesFile, Image, TextFile, Image, Text
First listed17 March 20269 July 2026
PublisherOpenAIOpenAI

Evidence: 4 public benchmark observations across 4 boards · 6 public benchmark observations across 6 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: GPT-5.4 Nano vs GPT-5.6 Terra

Public benchmark boards where GPT-5.4 Nano or GPT-5.6 Terra has a published result
BoardGPT-5.4 NanoGPT-5.6 TerraLeads
Arena codingArena (LMArena)14601454–1466High15181510–1525X-HighGPT-5.6 Terra
LMArena AgentLMArena—1.4%0.3%–2.6%X-HighOnly one result
ARC-AGI-2ARC Prize Foundation5.7%X-High83.9%MaxGPT-5.6 Terra
ARC-AGI-3ARC Prize Foundation—0.8%MaxOnly one result
AA Intelligence IndexArtificial Analysis20.7intelligence-index:v4.3:xhigh42.1intelligence-index:v4.3:maxGPT-5.6 Terra
AA τ²-Bench TelecomArtificial Analysis76.0%tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="GPT-5.4 nano (xhigh)":reasoning=true86.3%tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="GPT-5.6 Terra (max)":reasoning=trueGPT-5.6 Terra
AA Humanity's Last ExamArtificial Analysis28.3%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="GPT-5.4 nano (xhigh)":reasoning=true42.9%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="GPT-5.6 Terra (max)":reasoning=trueGPT-5.6 Terra
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-5.4 Nano vs GPT-5.6 Terra: common questions

Is GPT-5.4 Nano better than GPT-5.6 Terra?

GPT-5.6 Terra ranks higher on the ModelCap Index as of 22 September 2026: #21 against #81. 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-5.4 Nano cheaper than GPT-5.6 Terra?

GPT-5.4 Nano is cheaper on output tokens: $1.25/1M against $12.00/1M. Input tokens are $0.20/1M for GPT-5.4 Nano 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 $1.02 for GPT-5.4 Nano versus $10.00 for GPT-5.6 Terra. GPT-5.4 Nano costs 89.8% less in this scenario. 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-5.4 Nano or GPT-5.6 Terra?

GPT-5.6 Terra has the larger context window: 1M tokens against 400K.

Which is better for coding, GPT-5.4 Nano or GPT-5.6 Terra?

Arena coding: GPT-5.4 Nano 1460, GPT-5.6 Terra 1518 — GPT-5.6 Terra leads.

Are GPT-5.4 Nano and GPT-5.6 Terra open-weight models?

GPT-5.4 Nano: API only. GPT-5.6 Terra: API only. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.

Where can I run GPT-5.4 Nano and GPT-5.6 Terra?

ModelCap currently lists 2 API providers for GPT-5.4 Nano 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-5.4 Nano vs GPT-5.6 Terra comparison?

Every figure comes from the sealed ModelCap dataset published 22 September 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.

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