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AI Choice Engine

Model comparison

GLM 5.3 Flash vs GPT-6 Sol

Z.ai against OpenAI, compared on context, price, and verified benchmark results.

Catalog record checked September 26, 2026Individual provider fields may changeEvidence confidence: High — see receipts below

Z.ai

GLM 5.3 Flash

Balanced · Open weights

vs

OpenAI

GPT-6 Sol

Balanced

AI model capability comparison
SpecificationGLM 5.3 FlashGPT-6 Sol
ProviderZ.aiOpenAI
TierBalancedBalanced
Context window1.05MWinner: 1.05M
Max outputWinner: 131K128K
Input / 1M tokensWinner: $0.15$2
Output / 1M tokensWinner: $0.50$10
WeightsOpenClosed
Parameters320B total / 18B active (MoE)GPT-6 mid-price tier
Reasoning levelsNot verifiedUnverifiednone, low, medium, high, xhigh, max
Modalitiestext, image, videotext, image
LicenseMITNot disclosedUnverified
API model idglm-5.3-flashgpt-6-sol
ReleasedAugust 26, 2026September 22, 2026
Artificial Analysis Intelligence Index (2026-09-26)41.8Not verifiedUnverified
Artificial Analysis Intelligence Index [max] (2026-09-26)Not verifiedUnverified47.5
SWE-bench Verified (2026-09-01)92Not verifiedUnverified
Terminal-Bench 2.1 (2026-08)84.3Not verifiedUnverified
DeepSWE 1.1 (2026-08)63.4Not verifiedUnverified
DeepSWE 1.1 [max] (2026-09-22)Not verifiedUnverified68.8
Humanity's Last Exam (2026-08)55.3Not verifiedUnverified
OSWorld 2.0 (offline) [xhigh] (2026-09-22)Not verifiedUnverified60.5
Terminal-Bench 4.0 [max] (2026-09-26)Not verifiedUnverified43.9

Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Bold indicates the better figure where one is objectively better. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.

Benchmark receipts

Where each score comes from, and how far it can be compared across models.

Pricing tiers

GLM 5.3 Flash: $0.15/$0.50 per MTok on Z.ai's first-party API (cached input $0.03); third-party hosts (GMI, Novita, Together) list the same $0.15/$0.50. No promo tier is listed. The faster GLM-5.3-FlashX costs $0.37/$1.25.

GPT-6 Sol: Replaces GPT-5.6 Sol at 50% of its $4/$20 promo price. Cached input $0.20/MTok; cache writes $2.50 (1.25x). Above 272K input the whole request bills $4/$15 ($0.40 cached). Batch/Flex $1/$5; Fast mode $4/$20. Knowledge cutoff Apr 20 2026. Launched in the API, ChatGPT Work and Codex the same day.

BalancedOpen weightsRecord checked September 26, 2026

GLM 5.3 Flash

GLM 5.3 Flash is Z.ai's natively multimodal open-weight workhorse — 1M context, hybrid sparse/linear attention, near-flagship Intelligence Index at a fraction of the cost.

Best for

  • Cost-efficient long-context
  • Multimodal input
  • Coding agents

Watch out

Self-hosting needs ~186GB GPU memory at 4-bit (multi-GPU). Third-party hosts charge more than Z.ai's own API.

BalancedRecord checked September 26, 2026

GPT-6 Sol

GPT-6 Sol brings GPT-6 Astra's training advances to OpenAI's mid-priced tier — OpenAI claims roughly half GPT-5.6 Sol's factual-error rate at half its price, with a 1.05M-token context.

Best for

  • Default OpenAI production model
  • Agentic coding
  • Long-context knowledge work

Watch out

Brand-new (2026-09-22): the DeepSWE figure is vendor-reported and it is not yet on the independent boards; long prompts above 272K bill $4/$15 for the whole request.

When the cheaper one wins

GLM 5.3 Flash is cheaper on output at $0.50 per million tokens against $10 for GPT-6 Sol — about 20×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. These are standard-tier API rates, excluding batch and cache discounts.

Run the model picker

Evidence confidence: High

How strong and complete the evidence behind this comparison is — not a prediction of which model is better.

  • Pricing verified on both sides — Input and output rates are verified for both models.
  • 4/5 core specs verified on both sides — Not published for at least one side: reasoning levels.
  • 2 shared named benchmarks with differing scores — Measured on: Artificial Analysis Intelligence Index, DeepSWE 1.1.
  • Verified within the last 90 days — Newest catalog check was 2 days ago.
  • Both models carry source citations — Each side has at least two catalog sources on record.

Source receipts

Each catalog figure was checked against the provider or an independent second source on the date shown.

Related comparisons

Diving deeper on one model? GLM 5.3 Flash · GPT-6 Sol

Common questions

GLM 5.3 Flash vs GPT-6 Sol

Answered from the verified figures on this page rather than general guidance.

Is GLM 5.3 Flash or GPT-6 Sol cheaper for input?
GLM 5.3 Flash is cheaper at $0.15 per million input tokens, against $2 for GPT-6 Sol — roughly 13× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; GLM 5.3 Flash has tiered pricing: $0.15/$0.50 per MTok on Z.ai's first-party API (cached input $0.03); third-party hosts (GMI, Novita, Together) list the same $0.15/$0.50. No promo tier is listed. The faster GLM-5.3-FlashX costs $0.37/$1.25. GPT-6 Sol has tiered pricing: Replaces GPT-5.6 Sol at 50% of its $4/$20 promo price. Cached input $0.20/MTok; cache writes $2.50 (1.25x). Above 272K input the whole request bills $4/$15 ($0.40 cached). Batch/Flex $1/$5; Fast mode $4/$20. Knowledge cutoff Apr 20 2026. Launched in the API, ChatGPT Work and Codex the same day.
Is GLM 5.3 Flash or GPT-6 Sol cheaper for output?
GLM 5.3 Flash is cheaper at $0.50 per million output tokens, against $10 for GPT-6 Sol — roughly 20× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; GLM 5.3 Flash has tiered pricing: $0.15/$0.50 per MTok on Z.ai's first-party API (cached input $0.03); third-party hosts (GMI, Novita, Together) list the same $0.15/$0.50. No promo tier is listed. The faster GLM-5.3-FlashX costs $0.37/$1.25. GPT-6 Sol has tiered pricing: Replaces GPT-5.6 Sol at 50% of its $4/$20 promo price. Cached input $0.20/MTok; cache writes $2.50 (1.25x). Above 272K input the whole request bills $4/$15 ($0.40 cached). Batch/Flex $1/$5; Fast mode $4/$20. Knowledge cutoff Apr 20 2026. Launched in the API, ChatGPT Work and Codex the same day.
Which has the larger context window, GLM 5.3 Flash or GPT-6 Sol?
Both accept about 1.05M tokens of context, so document length will not decide between them.
Should I use GLM 5.3 Flash or GPT-6 Sol?
Both sit in the balanced tier, so the choice usually comes down to price and context rather than capability. GLM 5.3 Flash suits cost-efficient long-context; GPT-6 Sol suits default openai production model.
Can I self-host GLM 5.3 Flash or GPT-6 Sol?
GLM 5.3 Flash publishes open weights, but self-hosting and third-party provider access depend on the licence, hardware, serving support, and availability. GPT-6 Sol is a closed model whose supported access paths are controlled by its provider.

Next step

Choosing between them

The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.

  • Input price: GLM 5.3 Flash costs $0.15 per 1M tokens versus $2 for GPT-6 Sol — a 13.3x difference at the headline tier.
  • Context: GPT-6 Sol takes 1.05M against 1.05M for GLM 5.3 Flash — only decisive if your prompts approach the smaller window.
  • Measured capability: GPT-6 Sol leads Artificial Analysis Intelligence Index 47.5 to 41.8 (measured 2026-09-26).
  • Deployment: GLM 5.3 Flash publishes weights you can self-host; the other is API-only.
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