AI model comparison

gpt-oss-120b vs GLM 4.5 Air

Pricing, context window, benchmarks, and features compared side by side. Or skip the guesswork and send one prompt to both.

gpt-oss-120b is an open-weight, 117B-parameter Mixture-of-Experts (MoE) language model from OpenAI designed for high-reasoning, agentic, and general-purpose production use cases.

Input / 1M
$0.15
Output / 1M
$0.60
Context
131K

GLM-4.5-Air is the lightweight variant of our latest flagship model family, also purpose-built for agent-centric applications.

Input / 1M
$0.13
Output / 1M
$0.85
Context
131K

At a glance

Quick verdict

How the two models stack up on the things people ask about most.

Lower price

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gpt-oss-120b

1.1x cheaper for a typical chat

Higher intelligence score

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gpt-oss-120b

11.6 vs 11.1 on Artificial Analysis

Larger context window

Tie

131K vs 131K tokens

Newer release

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gpt-oss-120b

Released August 5, 2025

Benchmarks

Benchmark scores

Independent scores from Artificial Analysis. Higher is better.

Intelligence index

openai logogpt-oss-120b11.6
z-ai logoGLM 4.5 Air11.1

Coding index

openai logogpt-oss-120b30.4
z-ai logoGLM 4.5 AirNot available

Agentic index

openai logogpt-oss-120b3.7
z-ai logoGLM 4.5 AirNot available

Pricing

gpt-oss-120b vs GLM 4.5 Air API pricing

Per-token API rates. Cheaper option highlighted.

Metricopenai logogpt-oss-120bz-ai logoGLM 4.5 Air
Input tokensPer 1M tokens$0.15$0.13
Output tokensPer 1M tokens$0.60$0.85
Cached input (read)Per 1M tokens$0.08$0.03
Cache writePer 1M tokensNot availableNot available

What it costs in practice

Estimated cost per 1,000 requests at standard rates. Coding and long-document figures also show the cost when the input is already cached.

Chat message

2K in, 500 out

openai logogpt-oss-120b$0.60
z-ai logoGLM 4.5 Air$0.69

Coding task

30K in, 4K out

openai logogpt-oss-120b$6.90$4.65 cached
z-ai logoGLM 4.5 Air$7.30$4.15 cached

Long document summary

150K in, 2K out

openai logogpt-oss-120b$23.70$12.45 cached
z-ai logoGLM 4.5 Air$21.20$5.45 cached

Specs

Context window and capabilities

How much each model can read, how much it can write, and what it accepts as input.

Metricopenai logogpt-oss-120bz-ai logoGLM 4.5 Air
Context window131K tokens131K tokens
Max output66K tokens98K tokens
Input typesTextText
Output typesTextText
Reasoning effort levelsHigh, Medium, LowNot available
Default reasoning effortMediumNot available
Release dateAugust 5, 2025July 25, 2025

Features

Supported features

API features available for each model.

Metricopenai logogpt-oss-120bz-ai logoGLM 4.5 Air
Tool callingSupportedSupported
Structured outputsSupportedNot supported
JSON modeSupportedNot supported
ReasoningSupportedSupported
TemperatureSupportedSupported
Stop sequencesSupportedSupported
Deterministic seedSupportedSupported
Verbosity controlNot supportedNot supported

Our take

gpt-oss-120b is 1.1x cheaper for a typical chat. gpt-oss-120b scores higher on the Artificial Analysis Intelligence Index (11.6 vs 11.1). The right pick depends on your workload, so the quickest way to settle it is to send the same prompt to both and compare.

FAQ

Frequently asked questions

Is gpt-oss-120b or GLM 4.5 Air cheaper?

gpt-oss-120b is cheaper for a typical chat (2K input tokens and 500 output tokens). gpt-oss-120b costs $0.15 per 1M input tokens and $0.60 per 1M output tokens, while GLM 4.5 Air costs $0.13 per 1M input tokens and $0.85 per 1M output tokens.

Which has a bigger context window, gpt-oss-120b or GLM 4.5 Air?

gpt-oss-120b supports up to 131K tokens of context, compared with 131K for GLM 4.5 Air.

Is gpt-oss-120b smarter than GLM 4.5 Air?

On the Artificial Analysis Intelligence Index, gpt-oss-120b scores 11.6 and GLM 4.5 Air scores 11.1, putting gpt-oss-120b ahead. Benchmarks don't capture everything, so the best test is running your own prompts through both.

Can I use gpt-oss-120b and GLM 4.5 Air at the same time?

Yes. Shortcut Chat sends one prompt to multiple models at once, so you can see gpt-oss-120b and GLM 4.5 Air answer side by side and keep the better response.

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Why choose? Ask both.

Send one prompt to gpt-oss-120b and GLM 4.5 Air at the same time. Compare the answers side by side and keep the best one.