Head-to-head comparison

o3 vs GLM 5.2

o3 (OpenAI) and GLM 5.2 (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, GLM 5.2 holds the stronger ModelCap Index position (#11 vs #37); GLM 5.2 is 2.5× cheaper per output token ($3.15/1M vs $8.00/1M); GLM 5.2 offers the longer context window (1M vs 200K tokens); and GLM 5.2 ships open weights.

Which should you choose?

Choose o3 if…

ModelCap publishes no field on which o3 leads GLM 5.2 for this pair.

Choose GLM 5.2 if…

you want the stronger overall ModelCap Index position — #11 against #37 (73.6 vs 55.1 points).
API cost matters — $3.15/1M output tokens against $8.00/1M, about 2.5× cheaper.
your workload is prompt-heavy — input tokens cost $0.50/1M against $2.00/1M.
you need the longer context window — 1M tokens against 200K.
you want to self-host: GLM 5.2 ships open weights while o3 is api only.
you want provider choice — 27 listed API providers against 1.
Arena coding is your yardstick — 1506 against 1460.
ARC-AGI-2 is your yardstick — 22.8% against 6.5%.
Artificial Analysis Intelligence Index is your yardstick — 52.6 against 31.1.
you want the more recently listed model — GLM 5.2 was listed 16 June 2026, o3 16 April 2025.

o3 vs GLM 5.2: specs, pricing and context

Specification comparison of o3 and GLM 5.2
Field	o3OpenAI	GLM 5.2Z.ai
ModelCap Index position	#37	#11
Index score	55.1	73.6
Evidence	Measured	Measured
Input price / 1M tokens	$2.00	$0.50
Output price / 1M tokens	$8.00	$3.15
Context window	200K tokens	1M tokens
Max output tokens	100K	131K
API providers listed	1	27
Weight access	API only	Open weights
Input modalities	Image, Text, File	Text
First listed	16 April 2025	16 June 2026
Publisher	OpenAI	Z.ai

Evidence: 4 public benchmark observations across 4 boards · 6 public benchmark observations across 6 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: o3 vs GLM 5.2

Public benchmark boards where o3 or GLM 5.2 has a published result
Board	o3	GLM 5.2	Leads
Arena codingArena (LMArena)	14601453–1466	15061498–1514Max	GLM 5.2
LMArena AgentLMArena	—	6.7%5.8%–7.6%Max	Only one result
ARC-AGI-2ARC Prize Foundation	6.5%High	22.8%	GLM 5.2
SWE-benchSWE-bench (Princeton / SWE-agent team)	58.4%	—	Only one result
BFCL V4UC Berkeley (Gorilla)	63.1Prompt	—	Only one result
Artificial Analysis Intelligence IndexArtificial Analysis	31.1intelligence-index	52.6intelligence-index	GLM 5.2
WildClawBench OpenClawWildClawBench	—	54.2	Only 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.

o3 vs GLM 5.2: common questions

Is o3 better than GLM 5.2?

GLM 5.2 ranks higher on the ModelCap Index as of 18 August 2026: #11 against #37. 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 cheaper than GLM 5.2?

GLM 5.2 is cheaper on output tokens: $3.15/1M against $8.00/1M. Input tokens are $2.00/1M for o3 and $0.50/1M for GLM 5.2. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens.

Which has the bigger context window, o3 or GLM 5.2?

GLM 5.2 has the larger context window: 1M tokens against 200K.

Which is better for coding, o3 or GLM 5.2?

Arena coding: o3 1460, GLM 5.2 1506 — GLM 5.2 leads.

Are o3 and GLM 5.2 open-weight models?

o3: API only. GLM 5.2: 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 and GLM 5.2?

ModelCap currently lists 1 API provider for o3 and 27 for GLM 5.2, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this o3 vs GLM 5.2 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.