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Head-to-head comparison

GPT-5.4 Nano vs o3

GPT-5.4 Nano (OpenAI) and o3 (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, o3 holds the stronger ModelCap Index position (#53 vs #81); GPT-5.4 Nano is 6.4× cheaper per output token ($1.25/1M vs $8.00/1M); and GPT-5.4 Nano offers the longer context window (400K vs 200K tokens).

Which should you choose?

Choose GPT-5.4 Nano if…

  • API cost matters — $1.25/1M output tokens against $8.00/1M, about 6.4× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.20/1M against $2.00/1M.
  • you need the longer context window — 400K tokens against 200K.
  • you want provider choice — 2 listed API providers against 1.
  • AA Humanity's Last Exam is your yardstick — 28.3% against 20.1%.
  • you want the more recently listed model — GPT-5.4 Nano was listed 17 March 2026, o3 16 April 2025.

Choose o3 if…

  • you want the stronger overall ModelCap Index position — #53 against #81 (66.5 vs 57.3 points).
  • Arena coding is your yardstick — 1460 against 1460.
  • ARC-AGI-2 is your yardstick — 6.5% against 5.7%.
  • AA τ²-Bench Telecom is your yardstick — 80.7% against 76.0%.

GPT-5.4 Nano vs o3: specs, pricing and context

Specification comparison of GPT-5.4 Nano and o3
FieldGPT-5.4 NanoOpenAIo3OpenAI
ModelCap Index position#81#53
Index score57.366.5
EvidenceMeasuredMeasured
Input price / 1M tokens$0.20$2.00
Output price / 1M tokens$1.25$8.00
Context window400K tokens200K tokens
Max output tokens128K100K
API providers listed21
Weight accessAPI onlyAPI only
Input modalitiesFile, Image, TextImage, Text, File
First listed17 March 202616 April 2025
PublisherOpenAIOpenAI

Evidence: 4 public benchmark observations across 4 boards · 3 public benchmark observations across 3 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: GPT-5.4 Nano vs o3

Public benchmark boards where GPT-5.4 Nano or o3 has a published result
BoardGPT-5.4 Nanoo3Leads
Arena codingArena (LMArena)14601454–1466High14601454–1467o3
ARC-AGI-2ARC Prize Foundation5.7%X-High6.5%Higho3
SWE-benchSWE-bench (Princeton / SWE-agent team)—58.4%Only one result
BFCL V4UC Berkeley (Gorilla)—63.1PromptOnly one result
AA Intelligence IndexArtificial Analysis20.7intelligence-index:v4.3:xhigh—Only one result
AA τ²-Bench TelecomArtificial Analysis76.0%tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="GPT-5.4 nano (xhigh)":reasoning=true80.7%tau2:telecom:dual-control:pass-at-1:3-repeats:source-model="o3":reasoning=trueo3
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=true20.1%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="o3":reasoning=trueGPT-5.4 Nano

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 o3: common questions

Is GPT-5.4 Nano better than o3?

o3 ranks higher on the ModelCap Index as of 22 September 2026: #53 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 overlap, so the rank difference alone does not establish a reliable capability advantage for your workload.

Is GPT-5.4 Nano cheaper than o3?

GPT-5.4 Nano is cheaper on output tokens: $1.25/1M against $8.00/1M. Input tokens are $0.20/1M for GPT-5.4 Nano and $2.00/1M for o3. 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 $8.00 for o3. GPT-5.4 Nano costs 87.2% 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 o3?

GPT-5.4 Nano has the larger context window: 400K tokens against 200K.

Which is better for coding, GPT-5.4 Nano or o3?

Arena coding: GPT-5.4 Nano 1460, o3 1460 — o3 leads.

Are GPT-5.4 Nano and o3 open-weight models?

GPT-5.4 Nano: API only. o3: 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 o3?

ModelCap currently lists 2 API providers for GPT-5.4 Nano and 1 for o3, 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 o3 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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