Data verified: Sep 12, 2026, 12:29 AM UTC · Prices sourced from official provider pages. Verify current rates before production use.

GLM 5.3 Flash vs Grok 4.20

Price, context and performance head to head. Data synced from the provider catalog.

Quick verdict

Cheaper

GLM 5.3 Flash

Larger context

Grok 4.20

Faster

GLM 5.3 Flash

Higher quality

GLM 5.3 Flash

Head-to-head

Head-to-head
Feature	GLM 5.3 Flash	Grok 4.20
Provider	Z.AI	xAI
Tier	Budget	Mid-tier
Input per 1M tokens	$0.15	$1.25
Output per 1M tokens	$0.5	$2.5
Cached input per 1M	$0.03	$0.2
Context window	1.3M	2M
Intelligence index	42/100	—
Coding index	72/100	—
Agentic index	51/100	—
GPQA Diamond	0.87	—
Tau-bench (airline)	0.73	—
Speed	Fast	Standard
Vision (image input)	Yes	Yes
Function calling	Yes	Yes
Batch API	No	No

Estimated monthly cost

Enter how many requests per day you send with an average prompt (1K input + 1K output) and compare the monthly cost of both models.

Requests per day

GLM 5.3 Flash

$1.95

/ mo

Grok 4.20

$11.25

/ mo

GLM 5.3 Flash saves $9.3/mo vs Grok 4.20

Which one should I pick?

Pick GLM 5.3 Flash if cost is the priority: it's 83% cheaper than Grok 4.20 on an average prompt.
Pick Grok 4.20 if you need to process long documents: its context window is 2× larger.
Pick GLM 5.3 Flash if answer quality is the priority: it's better positioned for your use case.
Pick GLM 5.3 Flash if latency matters: it's noticeably faster.

Want us to build it for you?

We integrate GLM 5.3 Flash or Grok 4.20 into your product with caching, observability and continuous evaluation — typically 40-80% cheaper than the obvious first pick.

Talk to an expert

Related comparisons

Other combinations developers frequently compare in 2026.

GLM 4.7 FlashvsGrok 4.20

Frequently asked questions about AI models and pricing

What people ask us when comparing GPT, Claude, Gemini and the rest.

A token is the unit an AI model processes: usually between half a word and a full word. Rule of thumb: 1,000 tokens ≈ 750 English words. A 20-word sentence is about 26 tokens; a 300-word email is around 400. Models charge for input tokens (your prompt) and output tokens (their answer) separately.

When your app sends the same system prompt on every request (e.g. "You are a customer support agent for Acme…"), providers store it once and reuse the computation. They only charge full price for the new part (the user's question). OpenAI, Anthropic and Google give 50% to 90% off cached tokens. The calculator above accounts for this via a cache-hit % slider.

Chatbot: GPT-5.4 Mini or Claude Haiku 4.5 for latency; DeepSeek V3.2 for cost. Code: Claude Opus 4.6 and GPT-5.4 still lead the benchmarks, with o3 and DeepSeek R1 for hard reasoning. Document analysis: you need a large window — Gemini 3.1 Pro, Claude Opus or Llama 4 Maverick. Use the Model Finder above for a personalised pick.

Five levers: (1) cache system prompts (saves 50-90%), (2) batch API for non-urgent requests (50% off), (3) smaller model for simple tasks and flagship only when needed (complexity router), (4) trim prompts and cap output tokens, (5) fine-tune or use RAG instead of re-sending the same context every call. At Letbrand we audit each lever and typically cut costs by 40-80%.

GLM 5.3 Flash vs Grok 4.20

Price, context and performance head to head. Data synced from the provider catalog.

Quick verdict

Cheaper

GLM 5.3 Flash

Larger context

Grok 4.20

Faster

GLM 5.3 Flash

Higher quality

GLM 5.3 Flash

Head-to-head

Head-to-head
Feature	GLM 5.3 Flash	Grok 4.20
Provider	Z.AI	xAI
Tier	Budget	Mid-tier
Input per 1M tokens	$0.15	$1.25
Output per 1M tokens	$0.5	$2.5
Cached input per 1M	$0.03	$0.2
Context window	1.3M	2M
Intelligence index	42/100	—
Coding index	72/100	—
Agentic index	51/100	—
GPQA Diamond	0.87	—
Tau-bench (airline)	0.73	—
Speed	Fast	Standard
Vision (image input)	Yes	Yes
Function calling	Yes	Yes
Batch API	No	No

Estimated monthly cost

Enter how many requests per day you send with an average prompt (1K input + 1K output) and compare the monthly cost of both models.

Requests per day

GLM 5.3 Flash

$1.95

/ mo

Grok 4.20

$11.25

/ mo

GLM 5.3 Flash saves $9.3/mo vs Grok 4.20

Which one should I pick?

Pick GLM 5.3 Flash if cost is the priority: it's 83% cheaper than Grok 4.20 on an average prompt.
Pick Grok 4.20 if you need to process long documents: its context window is 2× larger.
Pick GLM 5.3 Flash if answer quality is the priority: it's better positioned for your use case.
Pick GLM 5.3 Flash if latency matters: it's noticeably faster.

Want us to build it for you?

We integrate GLM 5.3 Flash or Grok 4.20 into your product with caching, observability and continuous evaluation — typically 40-80% cheaper than the obvious first pick.

Talk to an expert