GLM 5 vs GPT-5.2

Z.ai · China  |  OpenAI · US · Updated June 2026

Quick verdict

Pick GLM 5 for agentic planning and long-horizon coding workflows or complex systems design and backend reasoning. Pick GPT-5.2 for strong all-round reasoning or reliable structured output. Choose GLM 5 if you need self-hosting or data privacy; GPT-5.2 if you want a managed API.

GLM 5 (Z.ai, China) and GPT-5.2 (OpenAI, US) line up two different AI ecosystems against each other — a comparison that is as much about cost philosophy and openness as raw capability. GLM 5 is z.ai's flagship open-weight (MIT) MoE foundation model, engineered for complex systems design and long-horizon agentic coding. GPT-5.2 is a capable GPT-5-generation all-rounder, now succeeded by GPT-5.5. They diverge most on price, context window and open vs. closed weights — each quantified below from the models' real specs.

Key differences at a glance

Side-by-side specs

SpecGLM 5GPT-5.2
ProviderZ.ai (China) OpenAI (US)
ReleasedFebruary 11, 2026 December 11, 2025
Context window200K (~300 pages) 400K (~600 pages)
Price (in/out)$1/$3.2 per 1M tokens $1.75/$14 per 1M tokens
Open weight?Yes — self-hostable No — API only
Modalitiestext, code text, image, code
SWE-Bench Verified77.8% Not published
MRCR v2 @ 1MNot published Not published

Who wins what

Agentic planning and long-horizon coding workflows

GLM 5

A core design strength of GLM 5.

Complex systems design and backend reasoning

GLM 5

A core design strength of GLM 5.

Iterative self-correction on autonomous tasks

GLM 5

A core design strength of GLM 5.

Strong all-round reasoning

GPT-5.2

A core design strength of GPT-5.2.

Reliable structured output

GPT-5.2

A core design strength of GPT-5.2.

Broad ecosystem and tooling

GPT-5.2

A core design strength of GPT-5.2.

Lowest cost at scale

GLM 5

At $1/$3.2 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.

Largest single-prompt input

GPT-5.2

Its 400K window is about 2× larger, fitting roughly 600 pages in one prompt.

Which should you pick?

A cost-sensitive startup shipping high volume

GLM 5

At $1/$3.2 per 1M tokens it undercuts GPT-5.2, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

GPT-5.2

Larger 400K window fits more in one prompt.

A team with data-privacy or self-hosting needs

GLM 5

Open weights let you run it on your own hardware; GPT-5.2 is API-only.

Anyone whose priority is agentic planning and long-horizon coding workflows

GLM 5

It is specifically built for that.

Anyone whose priority is strong all-round reasoning

GPT-5.2

That is its strongest area.

An enterprise with regional data-residency rules

GPT-5.2 or GLM 5

Origin (China vs US) affects where data is processed and which compliance regime applies — check the provider's terms for your region.

GLM 5: where it fits

Z.ai's flagship open-weight (MIT) MoE foundation model, engineered for complex systems design and long-horizon agentic coding. Released February 11, 2026 by Z.ai, it is built for agentic planning and long-horizon coding workflows, complex systems design and backend reasoning, iterative self-correction on autonomous tasks, and open weights under the permissive MIT license.

Its trade-offs are real: 200K context trails 1M-context rivals, and quickly superseded by GLM-5.1 and GLM-5.2. At $1 in / $3.2 out per million tokens, it sits in the budget price band.

GPT-5.2: where it fits

A capable GPT-5-generation all-rounder, now succeeded by GPT-5.5. Released December 11, 2025 by OpenAI, it is built for strong all-round reasoning, reliable structured output, broad ecosystem and tooling, and professional workflows.

Its trade-offs: superseded by GPT-5.5, and smaller context than flagships. At $1.75 in / $14 out per million tokens, it sits in the mid price band.

The bottom line for this matchup

The defining split here is open vs. closed. GLM 5 gives you weights you control — self-host it, fine-tune it, keep data in-house, pay only for hardware. GPT-5.2 gives you a managed, always-updated API with no infrastructure to run. Teams with GPUs, privacy requirements, or huge volume often favour the open model; teams that want zero ops and the latest capabilities favour the closed one. Capability is close enough that this operational question, not the benchmark, usually decides it.

Want both GLM 5 and GPT-5.2 without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.

See pricing

Frequently asked questions

Is GLM 5 or GPT-5.2 better for coding?

Public SWE-Bench figures are not available for GPT-5.2, so the honest test is your own repository — run an identical real bug through both. By design, GLM 5 leans toward agentic planning and long-horizon coding workflows while GPT-5.2 leans toward strong all-round reasoning, and that positioning usually predicts which feels better on your codebase.

Which is cheaper, GLM 5 or GPT-5.2?

GLM 5 is open-weight, so self-hosting means no per-token fee (you pay for hardware instead), while GPT-5.2 is API-metered at $1.75/$14 per 1M tokens. For most teams without GPUs, the API model is cheaper to start; at very high volume, self-hosting can win.

Which has the bigger context window?

GPT-5.2 — 400K vs 200K, about 2× larger. Useful only if the model actually reasons over the full window, which not all do.

Can I use both GLM 5 and GPT-5.2 together?

Yes — a multi-model platform like LumiChats gives you GLM 5, GPT-5.2 and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.

Which is newer, GLM 5 or GPT-5.2?

GLM 5 — released February 11, 2026, about 2 months after GPT-5.2.

Related comparisons

Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.