Model comparison

GLM 5.3 Flash vs Grok 4.5

Q: Is GLM 5.3 Flash or Grok 4.5 cheaper for input?

GLM 5.3 Flash is cheaper at $0.15 per million input tokens, against $2 for Grok 4.5 — 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 is the standard first-party and third-party rate (Z.ai docs; GMI, Novita, Together). A 50% promo tier runs $0.075/$0.25 — confirm which rate your account quotes. Grok 4.5 has tiered pricing: $2/$6 per MTok (<200K prompt); $4/$12 (≥200K). Cached input $0.30/MTok.

Q: Is GLM 5.3 Flash or Grok 4.5 cheaper for output?

GLM 5.3 Flash is cheaper at $0.50 per million output tokens, against $6 for Grok 4.5 — roughly 12× 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 is the standard first-party and third-party rate (Z.ai docs; GMI, Novita, Together). A 50% promo tier runs $0.075/$0.25 — confirm which rate your account quotes. Grok 4.5 has tiered pricing: $2/$6 per MTok (<200K prompt); $4/$12 (≥200K). Cached input $0.30/MTok.

Q: Which has the larger context window, GLM 5.3 Flash or Grok 4.5?

GLM 5.3 Flash accepts 1.05M tokens against 500K for Grok 4.5. This only matters if you routinely send very long documents or large codebases.

Q: Should I use GLM 5.3 Flash or Grok 4.5?

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; Grok 4.5 suits real-time data queries.

Q: Can I self-host GLM 5.3 Flash or Grok 4.5?

GLM 5.3 Flash publishes open weights, but self-hosting and third-party provider access depend on the licence, hardware, serving support, and availability. Grok 4.5 is a closed model whose supported access paths are controlled by its provider.

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

Catalog record checked September 5, 2026Individual provider fields may changeEvidence confidence: High — see receipts below

Z.ai

GLM 5.3 Flash

Balanced · Open weights

xAI

Grok 4.5

Balanced

AI model capability comparison
Specification	GLM 5.3 Flash	Grok 4.5
Provider	Z.ai	xAI
Tier	Balanced	Balanced
Context window	Winner: 1.05M	500K
Max output	131K	131K
Input / 1M tokens	Winner: $0.15	$2
Output / 1M tokens	Winner: $0.50	$6
Weights	Open	Closed
Parameters	320B total / 18B active (MoE)	Not disclosedUnverified
Reasoning levels	Not verifiedUnverified	low, medium, high
Modalities	text, image, video	text, image
License	MIT	Not disclosedUnverified
API model id	Not publishedUnverified	grok-4.5
Released	August 26, 2026	July 8, 2026
Artificial Analysis Intelligence Index (2026-08-26)	57	Not verifiedUnverified
Artificial Analysis Intelligence Index [high] (2026-08-14)	Not verifiedUnverified	56
SWE-bench Verified (2026-09-01)	92	Not verifiedUnverified
Terminal-Bench 2.1 (2026-08)	Winner: 84.3	83.3
DeepSWE 1.1 (2026-08)	Winner: 63.4	54
Humanity's Last Exam (2026-08)	55.3	Not verifiedUnverified

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

2026-09-01: vals.ai SWE-bench Verified leaderboard (independent, mini-swe-agent bash-only); not published by Z.aiReal GitHub issue resolution: does the model's patch pass the hidden tests. Comparability: comparable with caveat — Post-audit vendor claims and pre-audit scores sit on different task trust levels; scaffolding (agent harness, compute budget) also dominates results. Never aggregate across scaffolds.
2026-08-14: Artificial AnalysisComposite index blending reasoning, knowledge, and coding evals into one 0–100 score. Comparability: directly comparable — AA occasionally rebaselines the index scale between snapshots — a score captured on one date is only comparable to same-snapshot scores (check measuredAt).
2026-08: Z.ai GLM-5.3-Flash blog (vendor, mini-swe-agent, 400K context)Agentic software engineering: pass@1 on real repo tasks with reported cost per completed task. Comparability: directly comparable
2026-08: GLM-5.3-Flash HF model card (vendor, with tools, full set)Agentic terminal work: multi-step tasks executed in a sandboxed shell environment. Comparability: comparable with caveat — Scores across Terminal-Bench major versions (v1 vs v2) are NOT comparable; harness configuration (container, time limits) also shifts results.
2026-07-16: xAI — Introducing Grok 4.5 (vendor; Datacurve-run)Agentic terminal work: multi-step tasks executed in a sandboxed shell environment. Comparability: comparable with caveat — Scores across Terminal-Bench major versions (v1 vs v2) are NOT comparable; harness configuration (container, time limits) also shifts results.
2026-07: Google DeepMind 3.6 Flash evaluation report (independent tabulation; conflicts with xAI's 53 — both preserved)Agentic software engineering: pass@1 on real repo tasks with reported cost per completed task. Comparability: directly comparable

Pricing tiers: GLM 5.3 Flash: $0.15/$0.50 per MTok is the standard first-party and third-party rate (Z.ai docs; GMI, Novita, Together). A 50% promo tier runs $0.075/$0.25 — confirm which rate your account quotes. · Grok 4.5: $2/$6 per MTok (<200K prompt); $4/$12 (≥200K). Cached input $0.30/MTok.

BalancedOpen weightsRecord checked September 3, 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 5, 2026

Grok 4.5

Grok 4.5 is xAI's balanced model with a 500K context and real-time X integration.

Best for

Real-time data queries
Technical tasks
Cost-sensitive reasoning

Watch out

A step behind Grok 4.6; 500K context is smaller than the 1M-class models.

When the cheaper one wins

GLM 5.3 Flash is cheaper on output at $0.50 per million tokens against $6 for Grok 4.5 — about 12×. 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.
3/5 core specs verified on both sides — Not published for at least one side: parameter count, reasoning levels.
3 shared named benchmarks with differing scores — Measured on: Artificial Analysis Intelligence Index, Terminal-Bench 2.1, DeepSWE 1.1.
Verified within the last 90 days — Newest catalog check was 6 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.

GLM 5.3 Flash: Z.ai — GLM-5.3-Flash announcement (accessed 2026-08-29)
GLM 5.3 Flash: getdeploying — GLM-5.3-Flash reference (accessed 2026-08-29)
GLM 5.3 Flash: GMI Cloud — GLM-5.3-Flash analysis (accessed 2026-08-29)
Grok 4.5: xAI — Introducing Grok 4.5 (public launch 8 Jul 2026; formal announcement 16 Jul) (accessed 2026-08-29)
Grok 4.5: xAI pricing (grok-4.5 $2/$6, 500K) (accessed 2026-08-29)

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Diving deeper on one model? GLM 5.3 Flash · Grok 4.5

Common questions