API cost decision in 10 seconds

🔥Gemini 3.1 Pro Preview vs 🔥GLM 5.1

Pick GLM 5.1 for lower cost; pick Gemini 3.1 Pro Preview only if the larger context window matters more.

Pricing data updated: 2026-05-15T02:08:14Z Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick GLM 5.1 for lower cost; pick Gemini 3.1 Pro Preview only if the larger context window matters more.

On the standard 1M input plus 500K output workload, GLM 5.1 is estimated at $2.52 vs $8 for Gemini 3.1 Pro Preview, saving $5.48 (68.5% lower).

Cost-first pickGLM 5.1

Context-first pickGemini 3.1 Pro Preview

Sample savings$5.4868.5%

10x traffic gap$54.8

Gemini 3.1 Pro Preview has more context, but GLM 5.1 saves $5.48 on the standard workload. At 10x that traffic, the same price gap is about $54.8. Use the calculator below to replace the sample workload with your own token volume.

Cheaper input GLM 5.1 $2 vs $0.98 / 1M

GLM 5.1 is $1.02 cheaper per 1M input tokens (51% lower; 2.04x difference).

Cheaper output GLM 5.1 $12 vs $3.08 / 1M

GLM 5.1 is $8.92 cheaper per 1M output tokens (74.3% lower; 3.9x difference).

Larger context Gemini 3.1 Pro Preview 1.05M vs 202.75K

Gemini 3.1 Pro Preview has 845.82K more context (5.17x larger).

Sample workload GLM 5.1 $8 vs $2.52

GLM 5.1 is $5.48 cheaper on the standard workload (68.5% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.

Monthly input tokens Monthly output tokens

Gemini 3.1 Pro Preview Calculating… Estimated API cost

GLM 5.1 Calculating… Estimated API cost

Cheaper for this workload Calculating… Difference: calculating…

This estimate uses normalized public API pricing per 1M tokens. It is a planning aid, not a billing quote. Verify provider pricing, limits, and terms before production use.

Quick Decision

Verdict

GLM 5.1 has the lower input price; GLM 5.1 has the lower output price; Gemini 3.1 Pro Preview offers the larger context window. For the 1M input plus 500K output sample, GLM 5.1 is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $8 for Gemini 3.1 Pro Preview and $2.52 for GLM 5.1.

Best Fit

Choose Gemini 3.1 Pro Preview when you care most about larger context window.

Choose GLM 5.1 when you care most about lower input-token price, and lower output-token price.

Decision Notes

On the standard 1M input plus 500K output workload, GLM 5.1 is estimated at $2.52 vs $8 for Gemini 3.1 Pro Preview, saving $5.48 (68.5% lower).
GLM 5.1 is $5.48 cheaper on the standard workload (68.5% lower).
GLM 5.1 is $1.02 cheaper per 1M input tokens (51% lower; 2.04x difference).
GLM 5.1 is $8.92 cheaper per 1M output tokens (74.3% lower; 3.9x difference).
Gemini 3.1 Pro Preview has 845.82K more context (5.17x larger).

Head-to-Head Specs

Feature	🔥Gemini 3.1 Pro Preview (Google)	🔥GLM 5.1 (Z.ai)
Input Price prompt tokens per 1M	$2	$0.98
Completion Price per 1M tokens	$12	$3.08
Sample Workload Cost 1M input + 500K output	$8	$2.52
Context Window	1.05M	202.75K
Release Date	2026-02-19	2026-04-07
Popularity Rank current rank	#10	#20

Use-Case Decision Matrix

Use case	Better pick	Why
Budget-constrained production	GLM 5.1	On the standard 1M input plus 500K output workload, GLM 5.1 is estimated at $2.52 vs $8 for Gemini 3.1 Pro Preview, saving $5.48 (68.5% lower).
High-volume input processing	GLM 5.1	Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbots	GLM 5.1	Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document work	Gemini 3.1 Pro Preview	A larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps

Gemma 4 26B A4B (free) can replace Gemini 3.1 Pro Preview when lower sample workload cost matters most: $0.
Gemma 4 31B (free) can replace Gemini 3.1 Pro Preview when lower sample workload cost matters most: $0.
Lyria 3 Pro Preview can replace Gemini 3.1 Pro Preview when lower sample workload cost matters most: $0.
Lyria 3 Clip Preview can replace Gemini 3.1 Pro Preview when lower sample workload cost matters most: $0.

Larger context near this budget

Grok 4.1 Fast offers 2M context with $0.45 sample workload cost.
Grok 4.20 Multi-Agent offers 2M context with $5 sample workload cost.
Grok 4.20 offers 2M context with $2.5 sample workload cost.
Grok 4 Fast offers 2M context with $0.45 sample workload cost.

Popular competitors

Hy3 preview · Tencent · #1
Claude Opus 4.7 · Anthropic · #2
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DeepSeek V4 Flash · DeepSeek · #4

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Google catalog

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Z.ai catalog

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