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ModelCap

Head-to-head comparison

GLM 4.5 Air vs GLM 5.3

GLM 4.5 Air (Z.ai) and GLM 5.3 (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 2 October 2026

As of 2 October 2026, GLM 5.3 holds the stronger ModelCap Index position (#11 vs #125); GLM 4.5 Air is 5.2× cheaper per output token ($0.85/1M vs $4.40/1M); GLM 5.3 offers the longer context window (1M vs 131K tokens); and GLM 4.5 Air ships open weights.

Which should you choose?

Choose GLM 4.5 Air if…

  • API cost matters — $0.85/1M output tokens against $4.40/1M, about 5.2× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.13/1M against $1.40/1M.
  • you want to self-host: GLM 4.5 Air ships open weights while GLM 5.3 is restricted license.

Choose GLM 5.3 if…

  • you want the stronger overall ModelCap Index position — #11 against #125 (80.0 vs 46.7 points).
  • you need the longer context window — 1M tokens against 131K.
  • you want provider choice — 32 listed API providers against 3.
  • Arena text is your yardstick — 1479 against 1373.
  • Arena coding is your yardstick — 1521 against 1427.
  • AA Humanity's Last Exam is your yardstick — 42.3% against 7.0%.
  • you want the more recently listed model — GLM 5.3 was listed 18 August 2026, GLM 4.5 Air 25 July 2025.

GLM 4.5 Air vs GLM 5.3: specs, pricing and context

Specification comparison of GLM 4.5 Air and GLM 5.3
FieldGLM 4.5 AirZ.aiGLM 5.3Z.ai
ModelCap Index position#125#11
Index score46.780.0
EvidenceMeasuredMeasured
Input price / 1M tokens$0.13$1.40
Output price / 1M tokens$0.85$4.40
Context window131K tokens1M tokens
Declared route output cap98K131K
API providers listed332
Weight accessOpen weightsRestricted license
Input modalitiesTextText
First listed25 July 202518 August 2026
PublisherZ.aiZ.ai

Evidence: 2 public benchmark observations across 2 boards · 4 public benchmark observations across 4 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: GLM 4.5 Air vs GLM 5.3

Public benchmark boards where GLM 4.5 Air or GLM 5.3 has a published result
BoardGLM 4.5 AirGLM 5.3Leads
Arena textArena (LMArena)13731369–1378Not reported14791474–1485MaxGLM 5.3
Arena codingArena (LMArena)14271419–143415211512–1531MaxGLM 5.3
LMArena AgentLMArena—2.6%1.9%–3.3%MaxOnly one result
AA Intelligence IndexArtificial Analysis—44.8MaxOnly one result
AA Terminal-Bench 2.1Artificial Analysis—83.9%MaxOnly one result
AA τ²-Bench TelecomArtificial Analysis46.5%Reasoning—Only one result
AA Humanity's Last ExamArtificial Analysis7.0%Reasoning42.3%MaxGLM 5.3
Terminal-Bench 4.0Terminal-Bench (Laude Institute)—41.8%38.6%–45.1%Claude Code · MaxOnly one result

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.

GLM 4.5 Air vs GLM 5.3: common questions

Is GLM 4.5 Air better than GLM 5.3?

GLM 5.3 ranks higher on the ModelCap Index as of 2 October 2026: #11 against #125. 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 do not overlap, but the aggregate Index does not predict performance on every task; compare the relevant benchmark configurations before choosing.

Is GLM 4.5 Air cheaper than GLM 5.3?

GLM 4.5 Air is cheaper on output tokens: $0.85/1M against $4.40/1M. Input tokens are $0.13/1M for GLM 4.5 Air and $1.40/1M for GLM 5.3. 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 $0.69 for GLM 4.5 Air versus $5.00 for GLM 5.3. GLM 4.5 Air costs 86.3% 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, GLM 4.5 Air or GLM 5.3?

GLM 5.3 has the larger context window: 1M tokens against 131K. OpenRouter catalogue or provider-endpoint declaration. Limits can vary by provider and prompt length; a model-wide maximum has not been independently verified.

Which is better for coding, GLM 4.5 Air or GLM 5.3?

Arena coding: GLM 4.5 Air 1427, GLM 5.3 1521 — GLM 5.3 leads.

Are GLM 4.5 Air and GLM 5.3 open-weight models?

GLM 4.5 Air: Open weights. GLM 5.3: Restricted license. Open weights mean the checkpoint can be downloaded and self-hosted under its licence. A missing weight link does not identify every API or chat product that offers a model.

Where can I run GLM 4.5 Air and GLM 5.3?

ModelCap currently lists 3 API providers for GLM 4.5 Air and 32 for GLM 5.3, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this GLM 4.5 Air vs GLM 5.3 comparison?

Every figure and ModelCap Index position comes from the same published snapshot dated 2 October 2026. Publication and page updates happen separately; use the snapshot date shown on the page.

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