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GPT-5 nano vs o4

A complete head-to-head: pricing, context window, benchmarks, modality coverage, and openness, with a programmatic verdict synthesized from the underlying data.

Updated

GPT-5 nano specs · o4 specs
Verdict by category
  • PriceGPT-5 nano

    GPT-5 nano publishes pricing ($0.40 / 1M output tokens) while o4 does not.

  • Context windowGPT-5 nano

    GPT-5 nano accepts 400K tokens vs 200K, 2.0× the room for long documents and codebases.

  • BenchmarksTie

    No directly comparable public benchmarks are available for both models, check the spec sheets for individual scores.

  • ModalitiesTie

    Both handle text, vision.

  • OpennessTie

    Both are closed-weight, API-only.

On balance GPT-5 nano edges ahead, winning 2 of 5 categories against o4's 0. GPT-5 nano publishes pricing ($0.40 / 1M output tokens) while o4 does not. GPT-5 nano accepts 400K tokens vs 200K, 2.0× the room for long documents and codebases.

No directly comparable public benchmarks are available for both models, check the spec sheets for individual scores. Both target the same set of modalities (text, vision), so the deciding factors are price, context, and raw quality. Both are closed-weight, API-only.

o4 is the newer of the two, released 4 months after GPT-5 nano, which usually means a more recent knowledge cutoff and updated safety post-training. GPT-5 nano is usually picked for cheapest llm and fastest llm workloads, while o4 sees more deployments in reasoning and math. If pricing matters more than every last benchmark point, run the numbers in the calculator below before committing.

Side-by-side specs

SpecGPT-5 nanoo4
ProviderOpenAIOpenAI
ReleasedAug 2025Dec 2025
Modalitiestext, visiontext, vision
Context window400K tokens200K tokens
Max output128K tokens,
Input · 1M$0.050 / 1M tokensPricing not published
Output · 1M$0.40 / 1M tokensPricing not published
Knowledge cutoff2024-09,
Open weightsNoNo
API availableYesYes

Pricing at scale

What you'd actually pay at typical workloads. Numbers come from each model's published per-million-token rates.

  • Light usage, 100k in / 50k out per day$0.750 vs ,
  • Heavy usage, 1M in / 500k out per day$7.50 vs ,
  • RAG workload, 5M in / 200k out per day$9.90 vs ,

Light usage, 100k in / 50k out per day: pricing not directly comparable (one or both models are missing public per-token rates). Heavy usage, 1M in / 500k out per day: pricing not directly comparable (one or both models are missing public per-token rates). RAG workload, 5M in / 200k out per day: pricing not directly comparable (one or both models are missing public per-token rates).

Price calculator

Estimated spend for the listed models at your usage. Numbers are derived from each model's published per-million-token rates.

  • GPT-5 nano$0.025
  • o4Pricing unavailable

Benchmarks compared

Only sourced numbers. Where a benchmark is missing for one model we show the available value rather than fabricating the other.

Benchmark scores not yet available. We only publish numbers we can source from official model cards or independent leaderboards, see methodology.
Pick GPT-5 nano if

GPT-5 nano fits when…

  • Lowest-cost OpenAI model with vision support
  • Fast P99 latency
  • Good enough for routing and classification
  • Long-context tasks, handles 400K tokens vs 200K for o4.
Pick o4 if

o4 fits when…

  • Exceptional performance on hard math and reasoning benchmarks
  • Good at multi-step planning and verification
  • Strong scientific reasoning
Don't want either?

Consider GPT-5.5

OpenAI's mid-cycle GPT-5 refresh, improved reasoning, tool use, and multimodal grounding over the 2025 launch.

See GPT-5.5 specsGPT-5 nano vs GPT-5.5o4 vs GPT-5.5

Frequently asked

  • Is GPT-5 nano or o4 cheaper?
    Per-token pricing isn't published for at least one of these models, check each model's spec page for current rates.
  • Which has the larger context window?
    GPT-5 nano accepts 400K tokens vs 200K for o4.
  • Is GPT-5 nano or o4 better for coding?
    Both GPT-5 nano and o4 are competitive on coding benchmarks. See each model's individual spec page for HumanEval and SWE-bench scores where published. For an opinionated pick, consult our Best LLM for Coding ranking.
  • Are either of these models open source?
    Neither model ships open weights, both are accessible only via their respective providers' APIs.
  • When were GPT-5 nano and o4 released?
    GPT-5 nano was released by OpenAI on 2025-08-07. o4 was released by OpenAI on 2025-12-15.
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