Google: Gemini 3.1 Flash Lite Preview vs Z.ai: GLM 5.3 Flash

Neither wins outright: Google: Gemini 3.1 Flash Lite Preview is the pick when you need audio input, Z.ai: GLM 5.3 Flash when cost matters at scale.

Key numbers

SpecGoogle: Gemini 3.1 Flash Lite PreviewZ.ai: GLM 5.3 Flash
ProviderGoogleZ Ai
Input price (per 1M tokens)$0.25$0.15
Output price (per 1M tokens)$1.50$0.50
Blended price (3:1 input/output)$0.56$0.24
Cheaper than … of all models we track50%67%
Context window1.0M tokens (~1,573 pages)1.0M tokens (~1,573 pages)
Larger context than … of all models81%81%
Max output per response66K tokens (~49,200 words)944K tokens (~707,800 words)
Input typestext, image, video, file, audiotext, image, video
Output typestexttext
Free variantNoNo
Listed since2026-03-032026-08-26

What it costs for real workloads

Monthly cost at list price for five common workloads. Token counts per unit are stated so you can scale them to your own traffic. A workload that does not fit a model's context window is marked rather than priced.

Workload (per month)Google: Gemini 3.1 Flash Lite PreviewZ.ai: GLM 5.3 FlashDifference
Customer-support chatbot
50,000 conversations — each a 6-turn conversation (1,500 in / 400 out tokens)
$48.75$21.25Z.ai: GLM 5.3 Flash saves $27.50
RAG search over documents
20,000 questions — each a question answered from ~8 retrieved passages (6,000 in / 500 out tokens)
$45.00$23.00Z.ai: GLM 5.3 Flash saves $22.00
Coding / tool-using agent
2,000 tasks — each a multi-step task with tool calls and file context (60,000 in / 6,000 out tokens)
$48.00$24.00Z.ai: GLM 5.3 Flash saves $24.00
Batch summarisation
10,000 documents — each a 6,000-word report summarised to a page (8,000 in / 600 out tokens)
$29.00$15.00Z.ai: GLM 5.3 Flash saves $14.00
Long-document analysis
500 documents — each a 150-page contract or codebase read in one pass (100,000 in / 2,000 out tokens)
$14.00$8.00Z.ai: GLM 5.3 Flash saves $6.00

Capabilities side by side

CapabilityGoogle: Gemini 3.1 Flash Lite PreviewZ.ai: GLM 5.3 FlashWhat it lets you do
Tool / function calling✓ Yes✓ Yescall your APIs and run agent loops
Structured output (JSON schema)✓ Yes✓ Yesreturn JSON that validates against your schema
Reasoning / thinking mode✓ Yes✓ Yesspend extra tokens thinking before answering hard problems
Image input✓ Yes✓ Yesread screenshots, charts and scanned pages
Audio input✓ Yes—take speech or audio directly
File / PDF input✓ Yes—accept documents without your own parsing step
Image output——generate images, not just text
Built-in web search✓ Yes—answer from live web results
Seed (reproducible sampling)✓ Yes✓ Yesrepeat a generation for tests and evals
Log-probabilities—✓ Yesread token confidence for classification and scoring

From each model's published parameters and input/output types. “—” means not advertised, not proven absent.

Price history

DateModelInput / 1MOutput / 1M
2026-10-07Z.ai: GLM 5.3 Flash$0.15$0.50
2026-10-06Z.ai: GLM 5.3 Flash$0.03$0.50
2026-09-28Z.ai: GLM 5.3 Flash$0.15$0.50
2026-09-26Z.ai: GLM 5.3 Flash$0.04$0.50
2026-09-25Z.ai: GLM 5.3 Flash$0.04$0.60
2026-09-22Z.ai: GLM 5.3 Flash$0.15$0.50
2026-09-17Z.ai: GLM 5.3 Flash$0.09$0.30
2026-09-16Z.ai: GLM 5.3 Flash$0.10$0.33

Which should you choose?

Choose Google: Gemini 3.1 Flash Lite Preview if…

  • you need audio input — to take speech or audio directly; Z.ai: GLM 5.3 Flash does not advertise it
  • you need file / PDF input — to accept documents without your own parsing step; Z.ai: GLM 5.3 Flash does not advertise it
  • you need built-in web search — to answer from live web results; Z.ai: GLM 5.3 Flash does not advertise it

Choose Z.ai: GLM 5.3 Flash if…

  • cost matters at scale — it is 58% cheaper on a typical 3:1 input/output mix ($21.25 vs $48.75 a month for 50,000 support chats)
  • you need log-probabilities — to read token confidence for classification and scoring; Google: Gemini 3.1 Flash Lite Preview does not advertise it
  • you generate long outputs in one go — up to 944K tokens (about 707,800 words) per response
  • you want the newer model — released 2026-08-26, 6 months after the other

Frequently asked questions

Is Google: Gemini 3.1 Flash Lite Preview better than Z.ai: GLM 5.3 Flash?

Neither wins outright: Google: Gemini 3.1 Flash Lite Preview is the pick when you need audio input, Z.ai: GLM 5.3 Flash when cost matters at scale. In short: Google: Gemini 3.1 Flash Lite Preview when you need audio input, you need file / PDF input, you need built-in web search; Z.ai: GLM 5.3 Flash when cost matters at scale, you need log-probabilities, you generate long outputs in one go, you want the newer model.

Which is cheaper, Google: Gemini 3.1 Flash Lite Preview or Z.ai: GLM 5.3 Flash?

Z.ai: GLM 5.3 Flash is cheaper: $0.24 vs $0.56 per 1M tokens at a typical 3:1 input/output mix, 58% less. For 50,000 support conversations a month that is $21.25 against $48.75.

How much do Google: Gemini 3.1 Flash Lite Preview and Z.ai: GLM 5.3 Flash cost per million tokens?

Google: Gemini 3.1 Flash Lite Preview costs $0.25 per 1M input tokens and $1.50 per 1M output tokens; Z.ai: GLM 5.3 Flash costs $0.15 input and $0.50 output. Output tokens are billed separately, so long answers shift the gap.

Which has the bigger context window, Google: Gemini 3.1 Flash Lite Preview or Z.ai: GLM 5.3 Flash?

Both take 1.0M tokens per request — roughly 1,573 pages of text.

Do Google: Gemini 3.1 Flash Lite Preview and Z.ai: GLM 5.3 Flash support function calling and JSON output?

Tool calling — Google: Gemini 3.1 Flash Lite Preview: yes, Z.ai: GLM 5.3 Flash: yes. JSON-schema structured output — Google: Gemini 3.1 Flash Lite Preview: yes, Z.ai: GLM 5.3 Flash: yes.

Can Google: Gemini 3.1 Flash Lite Preview or Z.ai: GLM 5.3 Flash read images?

Yes, both accept image input.

Is Google: Gemini 3.1 Flash Lite Preview or Z.ai: GLM 5.3 Flash free to use?

No free variant is listed for either; both are pay-per-token.

What is the maximum output length of Google: Gemini 3.1 Flash Lite Preview and Z.ai: GLM 5.3 Flash?

Google: Gemini 3.1 Flash Lite Preview can write up to 66K tokens (about 49,200 words) per response; Z.ai: GLM 5.3 Flash up to 944K (about 707,800 words).

When were Google: Gemini 3.1 Flash Lite Preview and Z.ai: GLM 5.3 Flash released?

Google: Gemini 3.1 Flash Lite Preview was listed on 2026-03-03; Z.ai: GLM 5.3 Flash on 2026-08-26.

Has the price of Google: Gemini 3.1 Flash Lite Preview or Z.ai: GLM 5.3 Flash changed?

Google: Gemini 3.1 Flash Lite Preview: price unchanged since we started tracking it on 2026-03-10. Z.ai: GLM 5.3 Flash: input price raised 81% ($0.03 → $0.15/1M) on 2026-10-07 (10 price changes since 2026-08-27).

About the two models

Z Ai

Z.ai: GLM 5.3 Flash

GLM-5.3-Flash is a native multimodal model from Z.ai. It is suited for efficient coding and long-horizon agent tasks. Its hybrid sparse and linear attention architecture maintains accurate long-context behavior while...

Full Z.ai: GLM 5.3 Flash specs →

Compare Google: Gemini 3.1 Flash Lite Preview with other models

Compare Z.ai: GLM 5.3 Flash with other models

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