API cost decision in 10 seconds

🔥Gemini 2.5 Flash vs GLM 4.5 Air

Pick GLM 4.5 Air for lower cost; pick Gemini 2.5 Flash only if the larger context window matters more.

Page updated: 2026-05-26T19:08:13Z Data confirmed: 2026-05-26T19:08:13Z Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick GLM 4.5 Air for lower cost; pick Gemini 2.5 Flash only if the larger context window matters more.

On the standard 1M input plus 500K output workload, GLM 4.5 Air is estimated at $0.54 vs $1.55 for Gemini 2.5 Flash, saving $1.01 (64.8% lower).

Cost-first pickGLM 4.5 Air

Context-first pickGemini 2.5 Flash

Sample savings$1.0164.8%

10x traffic gap$10.05

Gemini 2.5 Flash has more context, but GLM 4.5 Air saves $1.01 on the standard workload. At 10x that traffic, the same price gap is about $10.05. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

GLM 4.5 Air stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shape	Token mix	Better pick	Gemini 2.5 Flash	GLM 4.5 Air
Input-heavy / RAG	5M input + 500K output	GLM 4.5 Air	$2.75	$1.04
Balanced workload	1M input + 1M output	GLM 4.5 Air	$2.8	$0.96
Output-heavy chatbot	1M input + 5M output	GLM 4.5 Air	$12.8	$4.33

Cheaper input GLM 4.5 Air $0.3 vs $0.125 / 1M

GLM 4.5 Air is $0.17 cheaper per 1M input tokens (58.3% lower; 2.4x difference).

Cheaper output GLM 4.5 Air $2.5 vs $0.84 / 1M

GLM 4.5 Air is $1.66 cheaper per 1M output tokens (66.4% lower; 2.98x difference).

Larger context Gemini 2.5 Flash 1.05M vs 131.07K

Gemini 2.5 Flash has 917.5K more context (8x larger).

Sample workload GLM 4.5 Air $1.55 vs $0.54

GLM 4.5 Air is $1.01 cheaper on the standard workload (64.8% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.

Monthly input tokens Monthly output tokens

Gemini 2.5 Flash Calculating… Estimated API cost

GLM 4.5 Air 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 4.5 Air has the lower input price; GLM 4.5 Air has the lower output price; Gemini 2.5 Flash offers the larger context window. For the 1M input plus 500K output sample, GLM 4.5 Air is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $1.55 for Gemini 2.5 Flash and $0.54 for GLM 4.5 Air.

Best Fit

Choose Gemini 2.5 Flash when you care most about larger context window.

Choose GLM 4.5 Air 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 4.5 Air is estimated at $0.54 vs $1.55 for Gemini 2.5 Flash, saving $1.01 (64.8% lower).
GLM 4.5 Air is $1.01 cheaper on the standard workload (64.8% lower).
GLM 4.5 Air is $0.17 cheaper per 1M input tokens (58.3% lower; 2.4x difference).
GLM 4.5 Air is $1.66 cheaper per 1M output tokens (66.4% lower; 2.98x difference).
Gemini 2.5 Flash has 917.5K more context (8x larger).

Head-to-Head Specs

Feature	🔥Gemini 2.5 Flash (Google)	GLM 4.5 Air (Z.ai)
Input Price prompt tokens per 1M	$0.3	$0.125
Completion Price per 1M tokens	$2.5	$0.84
Sample Workload Cost 1M input + 500K output	$1.55	$0.54
Context Window	1.05M	131.07K
Release Date	2025-06-17	2025-07-25
Popularity	#15	#37

Use-Case Decision Matrix

Use case	Better pick	Why
Budget-constrained production	GLM 4.5 Air	On the standard 1M input plus 500K output workload, GLM 4.5 Air is estimated at $0.54 vs $1.55 for Gemini 2.5 Flash, saving $1.01 (64.8% lower).
High-volume input processing	GLM 4.5 Air	Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbots	GLM 4.5 Air	Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document work	Gemini 2.5 Flash	A larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps

Gemma 4 31B (free) can replace Gemini 2.5 Flash when lower sample workload cost matters most: $0.
Gemma 4 26B A4B (free) can replace Gemini 2.5 Flash when lower sample workload cost matters most: $0.
Lyria 3 Clip Preview can replace Gemini 2.5 Flash when lower sample workload cost matters most: $0.
Lyria 3 Pro Preview can replace Gemini 2.5 Flash when lower sample workload cost matters most: $0.

Larger context near this budget

Llama 4 Scout offers 10M context with $0.23 sample workload cost.
Owl Alpha offers 1.05M context with $0 sample workload cost.

Popular competitors

DeepSeek V4 Flash · DeepSeek · #1
Hy3 preview · Tencent · #2
Claude Opus 4.7 · Anthropic · #3
Claude Sonnet 4.6 · Anthropic · #4

Cheaper alternatives

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Larger context alternatives

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Provider catalogs

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Google catalog

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Z.ai catalog

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Gemini 2.5 Flash

Gemini 2.5 Flash is Google's state-of-the-art workhorse model, specifically designed for advanced reasoning, coding, mathematics, and scientific tasks. It includes built-in "thinking" capabilities, enabling it to provide responses with greater...

GLM 4.5 Air

GLM-4.5-Air is the lightweight variant of our latest flagship model family, also purpose-built for agent-centric applications. Like GLM-4.5, it adopts the Mixture-of-Experts (MoE) architecture but with a more compact parameter...