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GPT-5 vs GPT-5.5

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

    GPT-5 publishes pricing ($10.00 / 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.

  • ModalitiesTie

    Both handle text, vision, audio.

  • OpennessTie

    Both are closed-weight, API-only.

On balance GPT-5 edges ahead, winning 1 of 5 categories against GPT-5.5's 0. GPT-5 publishes pricing ($10.00 / 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. Both target the same set of modalities (text, vision, audio), so the deciding factors are price, context, and raw quality. Both are closed-weight, API-only.

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

Side-by-side specs

SpecGPT-5GPT-5.5
ProviderOpenAIOpenAI
ReleasedAug 2025Mar 2026
Modalitiestext, vision, audiotext, vision, audio
Context window400K tokens400K tokens
Max output128K tokens,
Input · 1M$1.25 / 1M tokensPricing not published
Output · 1M$10.00 / 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$18.75 vs ,
  • Heavy usage, 1M in / 500k out per day$188 vs ,
  • RAG workload, 5M in / 200k out per day$248 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$0.625
  • GPT-5.5Pricing unavailable

Benchmarks compared

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

GPT-5GPT-5.5
  • MMLU91.4
  • HumanEval96.2
  • GPQA89.4
  • SWE-bench Verified74.9
Pick GPT-5 if

GPT-5 fits when…

  • Unified model, reasoning routed automatically per query
  • Excellent tool-use and JSON-mode discipline
  • Strong agent performance on SWE-bench Verified
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
Don't want either?

Consider GPT-5 mini

GPT-5's mid-tier sibling, most of the quality at a fraction of the price, ideal for high-volume production workloads.

See GPT-5 mini specsGPT-5 vs GPT-5 miniGPT-5.5 vs GPT-5 mini

Frequently asked

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