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GPT-5.5 vs GPT-5 nano

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

Updated

GPT-5.5 specs · GPT-5 nano specs
Verdict by category
  • PriceGPT-5 nano

    GPT-5 nano publishes pricing ($0.40 / 1M output tokens) while GPT-5.5 does not.

  • Context windowTie

    Both ship a 400K-token context window.

  • BenchmarksTie

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

  • ModalitiesGPT-5.5

    GPT-5.5 supports 3 modalities (text, vision, audio) vs 2 for GPT-5 nano.

  • OpennessTie

    Both are closed-weight, API-only.

It's a genuine coin-flip between GPT-5.5 and GPT-5 nano: 1 category wins each, with the rest tied. GPT-5 nano publishes pricing ($0.40 / 1M output tokens) while GPT-5.5 does not. Both ship a 400K-token context window.

No directly comparable public benchmarks are available for both models, check the spec sheets for individual scores. They differ in modality coverage, GPT-5.5 handles text, vision, audio while GPT-5 nano handles text, vision, which can be the deciding factor before you even look at benchmarks. Both are closed-weight, API-only.

GPT-5.5 is the newer of the two, released 7 months after GPT-5 nano, which usually means a more recent knowledge cutoff and updated safety post-training. GPT-5.5 is usually picked for agents and tool use workloads, while GPT-5 nano sees more deployments in cheapest llm and fastest llm. If pricing matters more than every last benchmark point, run the numbers in the calculator below before committing.

Side-by-side specs

SpecGPT-5.5GPT-5 nano
ProviderOpenAIOpenAI
ReleasedMar 2026Aug 2025
Modalitiestext, vision, audiotext, vision
Context window400K tokens400K tokens
Max output,128K tokens
Input · 1MPricing not published$0.050 / 1M tokens
Output · 1MPricing not published$0.40 / 1M tokens
Knowledge cutoff,2024-09
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, vs $0.750
  • Heavy usage, 1M in / 500k out per day, vs $7.50
  • RAG workload, 5M in / 200k out per day, vs $9.90

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-5.5Pricing unavailable
  • GPT-5 nano$0.025

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-5.5 if

GPT-5.5 fits when…

  • Industry-leading tool-use and function-calling reliability
  • Strong end-to-end agent performance across SWE-bench and GAIA
  • Wide ecosystem support, ChatGPT, Realtime API, Responses API
  • Multimodal needs covering audio.
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
Don't want either?

Consider GPT-5

OpenAI's unified flagship combining GPT-line breadth with built-in reasoning, replacing both GPT-4o and the o-series for most users.

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

Frequently asked

  • Is GPT-5.5 or GPT-5 nano 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?
    Both GPT-5.5 and GPT-5 nano ship a 400K-token context window.
  • Is GPT-5.5 or GPT-5 nano better for coding?
    Both GPT-5.5 and GPT-5 nano 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-5.5 and GPT-5 nano released?
    GPT-5.5 was released by OpenAI on 2026-03-01. GPT-5 nano was released by OpenAI on 2025-08-07.
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