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Head-to-head comparison

o3 Pro vs GLM 4.5 Air

o3 Pro (OpenAI) and GLM 4.5 Air (Z.ai) 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 18 August 2026

As of 18 August 2026, o3 Pro holds the stronger ModelCap Index position (#53 vs #68); GLM 4.5 Air is 94.1× cheaper per output token ($0.85/1M vs $80.00/1M); o3 Pro offers the longer context window (200K vs 131K tokens); and GLM 4.5 Air ships open weights.

Which should you choose?

Choose o3 Pro if…

  • you want the stronger overall ModelCap Index position — #53 against #68 (46.5 vs 36.9 points).
  • you need the longer context window — 200K tokens against 131K.
  • Artificial Analysis Intelligence Index is your yardstick — 33.3 against 16.7.

Choose GLM 4.5 Air if…

  • API cost matters — $0.85/1M output tokens against $80.00/1M, about 94.1× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.13/1M against $20.00/1M.
  • you want to self-host: GLM 4.5 Air ships open weights while o3 Pro is api only.
  • you want provider choice — 3 listed API providers against 1.
  • you want the more recently listed model — GLM 4.5 Air was listed 25 July 2025, o3 Pro 10 June 2025.

o3 Pro vs GLM 4.5 Air: specs, pricing and context

Specification comparison of o3 Pro and GLM 4.5 Air
Fieldo3 ProOpenAIGLM 4.5 AirZ.ai
ModelCap Index position#53#68
Index score46.536.9
EvidenceMeasuredMeasured
Input price / 1M tokens$20.00$0.13
Output price / 1M tokens$80.00$0.85
Context window200K tokens131K tokens
Max output tokens100K98K
API providers listed13
Weight accessAPI onlyOpen weights
Input modalitiesText, File, ImageText
First listed10 June 202525 July 2025
PublisherOpenAIZ.ai

Evidence: 1 public benchmark observation across 1 board · 3 public benchmark observations across 3 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: o3 Pro vs GLM 4.5 Air

Public benchmark boards where o3 Pro or GLM 4.5 Air has a published result
Boardo3 ProGLM 4.5 AirLeads
Arena codingArena (LMArena)—14261419–1434Only one result
Artificial Analysis Intelligence IndexArtificial Analysis33.3intelligence-index16.7intelligence-indexo3 Pro

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.

o3 Pro vs GLM 4.5 Air: common questions

Is o3 Pro better than GLM 4.5 Air?

o3 Pro ranks higher on the ModelCap Index as of 18 August 2026: #53 against #68. 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.

Is o3 Pro cheaper than GLM 4.5 Air?

GLM 4.5 Air is cheaper on output tokens: $0.85/1M against $80.00/1M. Input tokens are $20.00/1M for o3 Pro and $0.13/1M for GLM 4.5 Air. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens.

Which has the bigger context window, o3 Pro or GLM 4.5 Air?

o3 Pro has the larger context window: 200K tokens against 131K.

Which is better for coding, o3 Pro or GLM 4.5 Air?

The two models do not share a coding benchmark board on ModelCap yet, so no head-to-head coding score is published; the ModelCap Index position is the closest overall signal.

Are o3 Pro and GLM 4.5 Air open-weight models?

o3 Pro: API only. GLM 4.5 Air: Open weights. 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 o3 Pro and GLM 4.5 Air?

ModelCap currently lists 1 API provider for o3 Pro and 3 for GLM 4.5 Air, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this o3 Pro vs GLM 4.5 Air comparison?

Every figure comes from the sealed ModelCap dataset published 18 August 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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