Which is more cost-effective, Gemini 3.1 Pro or Gemini 4 Argon?

Based on 1M input + 1M output tokens, Gemini 3.1 Pro costs $14.00/month versus Gemini 4 Argon at $12.00/month. The cheaper option depends on your token volume and prompt-to-completion ratio. Use the interactive calculator on this page to enter your exact usage.

How accurate is this cost comparison?

List prices come from each provider's own pricing page and every model page shows when they were last verified. The capability scores are iOPTERA's editorial composites — informed by public benchmarks, not benchmark results themselves; the methodology page explains how they are set.

Which model scores higher on benchmarks?

Gemini 3.1 Pro scores 88 in coding and 89 in reasoning benchmarks. Gemini 4 Argon scores 98 in coding and 98 in reasoning. See the full 5-category breakdown in the Benchmark Comparison section above.

What are the context window sizes of Gemini 3.1 Pro and Gemini 4 Argon?

Gemini 3.1 Pro supports a 1.0M-token context window while Gemini 4 Argon supports 1.0M tokens. A larger context window lets you process more text in a single API call.

Which model is faster for real-time applications?

Gemini 3.1 Pro has a speed score of 82/100 and Gemini 4 Argon scores 70/100 on our latency benchmark. For interactive chatbots and low-latency tasks, the higher speed score is preferable.

Can I calculate costs for my specific token volume?

Yes. Use the interactive cost calculator on this page. Enter your monthly token volume and adjust the prompt-to-completion ratio. You can also use presets for common scenarios like Customer Support Bots (~30M tokens/month) or Document Summarizers (~15M tokens/month).

Cost and performance comparison

Gemini 3.1 Pro vs Gemini 4 Argon

Model AGoogle

Gemini 3.1 Pro

Capability score (editorial)89/100

Cost / 1M Tokens: $5.00; 70% in · 30% out mix
Value Index (score÷cost): 18.4; Higher = better value

Speed: 82/100
Context: 1.0M
Tier: Smart Tier

List price from the Google pricing page, verified October 19, 2026.

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How we verify prices

Model BGoogle

Gemini 4 Argon

Capability score (editorial)98/100

Cost / 1M Tokens: $4.40; 70% in · 30% out mix
Value Index (score÷cost): 23.0; Higher = better value

Speed: 70/100
Context: 1.0M
Tier: Power Tier

List price from the Google pricing page, verified October 19, 2026.

Introductory price until November 30, 2026; $4.00 / $20.00 from the day after.

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How we verify prices

In-depth analysis

Gemini 3.1 Pro vs Gemini 4 Argon: Detailed Comparison

Gemini 3.1 Pro is Google's mid-range-tier language model with a 1.0M-token context window, excelling at vision/multimodal. Gemini 4 Argon from Google is a flagship-tier model supporting 1.0M tokens in context, with standout performance in coding.

Price is not the deciding factor here. For the same text, Gemini 4 Argon and Gemini 3.1 Pro land within 12% of each other, which is inside the margin your own input/output ratio will move anyway. Pick on capability, context, or latency instead — the monthly bill will look much the same either way. Gemini 3.1 Pro is priced at $2.00/M input tokens and $12.00/M output tokens. Gemini 4 Argon costs $2.00/M input and $10.00/M output.

On iOPTERA's editorial scores, Gemini 4 Argon leads with 98/100 for coding and 98/100 for reasoning, against Gemini 3.1 Pro's 88/100 and 89/100.

Capability breakdown

Across the five core benchmark categories, here is how Gemini 3.1 Pro and Gemini 4 Argon stack up head to head:

coding

Gemini 4 leads

reasoning

Gemini 4 leads

data extraction

Gemini 4 leads

creative tasks

Gemini 4 leads

vision/multimodal

Gemini 4 leads

Best model by task

coding: Gemini 4 Argon wins with 98/100
reasoning: Gemini 4 Argon wins with 98/100
data extraction: Gemini 4 Argon wins with 96/100
creative tasks: Gemini 4 Argon wins with 96/100
vision/multimodal: Gemini 4 Argon wins with 98/100

Estimated monthly cost at scale

For 10M + 2M tokens of text a month (counted the way OpenAI's tokenizer counts), Gemini 3.1 Pro runs about $42.68 while Gemini 4 Argon runs about $38.80 — Gemini 4 Argon saves roughly $3.88 (9%) every month.

What actually decides it

Both models come from Google, so they share a tokenizer, an API surface, and a billing account. Switching between them is a model-string change and nothing else — no new SDK, no re-tokenizing your prompts to re-estimate cost, no second vendor to onboard. That makes routing between them far cheaper to implement than a cross-vendor split.

Gemini 4 Argon and Gemini 3.1 Pro were released within 8 months of each other, so they are competing on the same evaluations under roughly the same conditions. That makes a direct benchmark comparison meaningful here in a way it usually is not — neither model has the advantage of being measured on a newer, easier set of tests.

Context is effectively a tie: 1.0M against 1.0M. Neither model unlocks a document size the other cannot handle, so this axis should not enter the decision. If you were hoping context would break the tie for you, it will not.

Throughput is close enough to ignore — 82/100 versus 70/100. Neither model will feel noticeably quicker in an interactive product, so latency is not a reason to choose between them.

With prices this close (12% apart), pick on fit rather than cost. Gemini 4 Argon holds the benchmark edge; weigh that against where each one is weakest — coding and data extraction respectively — and use the calculator above with your own token mix.

What you actually pay

The list price is only the start. Prompt caching, batch processing and long prompts change the bill, and each provider sets them differently. Prices per 1M tokens.

Pricing terms beyond the list price, per 1M tokens
Pricing term	Gemini 3.1 Pro	Gemini 4 Argon
List price (input / output)	$2.00 / $12.00	$2.00 / $10.00
Cached input	$0.2010% of the input price	$0.105% of the input price
Batch API	50% off input and output	50% off input and output
Long prompts	Over 200K tokens: $4.00 / $18.00	No surcharge across the 1.05M window
Input with 80% cache hits	$0.56	$0.48

With 80% of input served from the cache, Gemini 4 Argon costs 14% less than Gemini 3.1 Pro for the same input text, counting each model's tokenizer.The tokenizer factor for Gemini 3.1 Pro, Gemini 4 Argon is our estimate until it is measured.

The last row assumes 80% of input tokens are read from the cache, as in a chat app that re-sends a long system prompt or RAG over the same documents. Cache-write and storage charges are not included.

Gemini also bills cache storage by the hour.

Checked on October 8, 2026 against the pricing pages of Google.

Capability scores

iOPTERA editorial scores across 5 categories — informed by public benchmarks, not measured by us

CategoryGemini 3.1Gemini 4Winner

Coding

Reasoning

Extraction

Creative

Vision

Gemini 3.1 Pro: 0 wins

Gemini 4 Argon: 5 wins

Gemini 4 Argon leads overall

Speed Score

82/100vs70/100

GeminiGemini

Context Window

1049Kvs1049K

GeminiGemini

What Is a Token?

Models don't read words — they process tokens.

A token is roughly 4 characters of English text (~¾ of a word). Your API bill is priced per million tokens — understanding this directly reduces your costs.

Short phrase

"Hello, world!"

4 tokens

Gemini 3.1 Pro: $0.78
Gemini 4 Argon: $0.78

Business email

One typical email (~200 words)

~270 tokens

Gemini 3.1 Pro: $52.38
Gemini 4 Argon: $52.38

Code file

50-line Python script

~400 tokens

Gemini 3.1 Pro: $77.60
Gemini 4 Argon: $77.60

Prices shown are for 100,000 runs of each workload — one run costs a fraction of a cent on both Gemini 3.1 Pro and Gemini 4 Argon, so the number only becomes meaningful at production volume. Input tokens only; add your output volume in the calculator below.

How to check your token usage

response.usage.total_tokens

Every API response includes a usage object. Sum total_tokens across all calls to get your monthly figure, then use the calculator below.

Your Cost Calculator

Enter your actual monthly token usage to see real savings

Quick Presets

Monthly Token Volume

30M tokens

Prompt / Completion Split

Prompt 70%Completion 30%

Gemini 3.1 Pro

$145.50/mo

$1,746.00/yr

$2.00/M input$12.00/M output

Cheaper

Gemini 4 Argon

$128.04/mo

$1,536.48/yr

$2.00/M input$10.00/M output

Annual Savings

$209.52 saved per year

Gemini 4 Argon cheaper · $17.46/mo

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