API cost decision in 10 seconds

GPT-5.1 vs Gemini 2.5 Flash Lite Preview 09-2025

Pick Gemini 2.5 Flash Lite Preview 09-2025 when budget and context both matter.

Page updated: 2026-05-26T15:08:08Z Data confirmed: 2026-05-26T19:08:13Z Prices normalized to USD per 1M tokens Sample workload: 1M input + 500K output

Budget verdict

Pick Gemini 2.5 Flash Lite Preview 09-2025 when budget and context both matter.

On the standard 1M input plus 500K output workload, Gemini 2.5 Flash Lite Preview 09-2025 is estimated at $0.3 vs $6.25 for GPT-5.1, saving $5.95 (95.2% lower).

Cost-first pickGemini 2.5 Flash Lite Preview 09-2025

Context-first pickGemini 2.5 Flash Lite Preview 09-2025

Sample savings$5.9595.2%

10x traffic gap$59.5

Gemini 2.5 Flash Lite Preview 09-2025 is cheaper on the standard workload and also has the larger context window. At 10x that traffic, the same price gap is about $59.5. Use the calculator below to replace the sample workload with your own token volume.

Cost sensitivity

Workload Sensitivity

Same prices, different token mixes.

Gemini 2.5 Flash Lite Preview 09-2025 stays cheaper across input-heavy, balanced, and output-heavy sample workloads.

Workload shape	Token mix	Better pick	GPT-5.1	Gemini 2.5 Flash Lite Preview 09-2025
Input-heavy / RAG	5M input + 500K output	Gemini 2.5 Flash Lite Preview 09-2025	$11.25	$0.7
Balanced workload	1M input + 1M output	Gemini 2.5 Flash Lite Preview 09-2025	$11.25	$0.5
Output-heavy chatbot	1M input + 5M output	Gemini 2.5 Flash Lite Preview 09-2025	$51.25	$2.1

Cheaper input Gemini 2.5 Flash Lite Preview 09-2025 $1.25 vs $0.1 / 1M

Gemini 2.5 Flash Lite Preview 09-2025 is $1.15 cheaper per 1M input tokens (92% lower; 12.5x difference).

Cheaper output Gemini 2.5 Flash Lite Preview 09-2025 $10 vs $0.4 / 1M

Gemini 2.5 Flash Lite Preview 09-2025 is $9.6 cheaper per 1M output tokens (96% lower; 25x difference).

Larger context Gemini 2.5 Flash Lite Preview 09-2025 400K vs 1.05M

Gemini 2.5 Flash Lite Preview 09-2025 has 648.58K more context (2.62x larger).

Sample workload Gemini 2.5 Flash Lite Preview 09-2025 $6.25 vs $0.3

Gemini 2.5 Flash Lite Preview 09-2025 is $5.95 cheaper on the standard workload (95.2% lower).

Estimate your workload cost

Your Workload Cost

Prices are normalized to USD per 1M tokens.

Monthly input tokens Monthly output tokens

GPT-5.1 Calculating… Estimated API cost

Gemini 2.5 Flash Lite Preview 09-2025 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

Gemini 2.5 Flash Lite Preview 09-2025 has the lower input price; Gemini 2.5 Flash Lite Preview 09-2025 has the lower output price; Gemini 2.5 Flash Lite Preview 09-2025 offers the larger context window. For the 1M input plus 500K output sample, Gemini 2.5 Flash Lite Preview 09-2025 is cheaper for the standard workload.

For a 1M input token plus 500K output token workload, the estimated API cost is $6.25 for GPT-5.1 and $0.3 for Gemini 2.5 Flash Lite Preview 09-2025.

Best Fit

Choose GPT-5.1 when its provider, model quality, latency, or availability is more important than the numeric price/context winner.

Choose Gemini 2.5 Flash Lite Preview 09-2025 when you care most about lower input-token price, lower output-token price, and larger context window.

Decision Notes

On the standard 1M input plus 500K output workload, Gemini 2.5 Flash Lite Preview 09-2025 is estimated at $0.3 vs $6.25 for GPT-5.1, saving $5.95 (95.2% lower).
Gemini 2.5 Flash Lite Preview 09-2025 is $5.95 cheaper on the standard workload (95.2% lower).
Gemini 2.5 Flash Lite Preview 09-2025 is $1.15 cheaper per 1M input tokens (92% lower; 12.5x difference).
Gemini 2.5 Flash Lite Preview 09-2025 is $9.6 cheaper per 1M output tokens (96% lower; 25x difference).
Gemini 2.5 Flash Lite Preview 09-2025 has 648.58K more context (2.62x larger).

Head-to-Head Specs

Feature	GPT-5.1 (OpenAI)	Gemini 2.5 Flash Lite Preview 09-2025 (Google)
Input Price prompt tokens per 1M	$1.25	$0.1
Completion Price per 1M tokens	$10	$0.4
Sample Workload Cost 1M input + 500K output	$6.25	$0.3
Context Window	400K	1.05M
Release Date	2025-11-13	2025-09-25
Popularity	#54	#75

Use-Case Decision Matrix

Use case	Better pick	Why
Budget-constrained production	Gemini 2.5 Flash Lite Preview 09-2025	On the standard 1M input plus 500K output workload, Gemini 2.5 Flash Lite Preview 09-2025 is estimated at $0.3 vs $6.25 for GPT-5.1, saving $5.95 (95.2% lower).
High-volume input processing	Gemini 2.5 Flash Lite Preview 09-2025	Lower prompt-token price matters most when prompts, retrieved passages, or documents dominate the bill.
Long responses and chatbots	Gemini 2.5 Flash Lite Preview 09-2025	Lower output-token price matters most when assistants generate many completion tokens.
RAG or long-document work	Gemini 2.5 Flash Lite Preview 09-2025	A larger context window leaves more room for retrieved passages, conversation history, or source files.

Related Alternatives

Same-provider lower-cost swaps

gpt-oss-120b (free) can replace GPT-5.1 when lower sample workload cost matters most: $0.
gpt-oss-20b (free) can replace GPT-5.1 when lower sample workload cost matters most: $0.
gpt-oss-20b can replace GPT-5.1 when lower sample workload cost matters most: $0.1.
gpt-oss-120b can replace GPT-5.1 when lower sample workload cost matters most: $0.13.

Larger context near this budget

Llama 4 Scout offers 10M context with $0.23 sample workload cost.
Grok 4.20 offers 2M context with $2.5 sample workload cost.
Grok 4.20 Multi-Agent offers 2M context with $5 sample workload cost.
Owl Alpha offers 1.05M context with $0 sample workload cost.

Popular competitors

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Hy3 preview · Tencent · #2
Claude Opus 4.7 · Anthropic · #3
Claude Sonnet 4.6 · Anthropic · #4

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Provider catalogs

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OpenAI catalog

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Google catalog

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