Which is more cost-effective, Gemini 3.1 Pro or Claude 3.5 Sonnet?

Based on 1M input + 1M output tokens, Gemini 3.1 Pro costs $14.00/month versus Claude 3.5 Sonnet at $18.00/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. Claude 3.5 Sonnet scores 88 in coding and 89 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 Claude 3.5 Sonnet?

Gemini 3.1 Pro supports a 1.0M-token context window while Claude 3.5 Sonnet supports 200K 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 Claude 3.5 Sonnet scores 95/100 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 Claude 3.5 Sonnet

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 26, 2026.

Check the source

How we verify prices

Model BAnthropic

Claude 3.5 Sonnet

Capability score (editorial)89/100

Cost / 1M Tokens: $6.60; 70% in · 30% out mix; ≈ $7.26 for the same text, tokenizer included
Value Index (score÷cost): 12.3; Higher = better value

Speed: 95/100
Context: 200K
Tier: Smart Tier

Last list price before the model was retired.

Its tokenizer produces about 10% more tokens than OpenAI's for the same text, so the real cost runs higher than the list price suggests. This is an estimate: the tokenizer has not been measured yet.

How we verify prices

In-depth analysis

Gemini 3.1 Pro vs Claude 3.5 Sonnet: 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. Claude 3.5 Sonnet from Anthropic is a mid-range-tier model supporting 200K tokens in context, with standout performance in creative tasks.

Gemini 3.1 Pro is both the cheaper and the stronger model here — for the same text it costs 33% less than Claude 3.5 Sonnet and still leads on combined coding and reasoning by 0 points. There is no tradeoff to weigh on this pair: unless you need something specific from Claude 3.5 Sonnet, the cheaper model is simply the better one. Gemini 3.1 Pro is priced at $2.00/M input tokens and $12.00/M output tokens. Claude 3.5 Sonnet costs $3.00/M input and $15.00/M output.

Claude 3.5 Sonnet turns the same text into about 13% more tokens than Gemini 3.1 Pro, because their tokenizers differ — so comparing list prices per token understates what Claude 3.5 Sonnet costs. For the same text, split 70% input and 30% output and counted the way OpenAI's tokenizer counts it, Claude 3.5 Sonnet works out at about $7.26 per million tokens and Gemini 3.1 Pro at $4.85. Every cost figure on this page includes that difference.

On iOPTERA's editorial scores, Gemini 3.1 Pro leads with 88/100 for coding and 89/100 for reasoning, against Claude 3.5 Sonnet's 88/100 and 89/100.

Capability breakdown

Across the five core benchmark categories, here is how Gemini 3.1 Pro and Claude 3.5 Sonnet stack up head to head:

coding

Tie

reasoning

Tie

data extraction

Tie

creative tasks

Claude 3.5 leads

vision/multimodal

Gemini 3.1 leads

Best model by task

creative tasks: Claude 3.5 Sonnet wins with 91/100
vision/multimodal: Gemini 3.1 Pro wins with 95/100

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 Claude 3.5 Sonnet runs about $66.00 — Gemini 3.1 Pro saves roughly $23.32 (35%) every month.

What actually decides it

Gemini 3.1 Pro and Claude 3.5 Sonnet come from different labs, which means different tokenizers, different API shapes, and a second vendor relationship. The same English text does not produce the same token count on both, so a price-per-million comparison understates the difference — measure your own prompts on each before treating the headline rates as the full story.

Gemini 3.1 Pro and Claude 3.5 Sonnet are 20 months apart, which is more than one generation in this market. Benchmark comparisons across that gap flatter the older model: it was measured against the evaluations that existed at the time. Treat Claude 3.5 Sonnet's scores as a floor for what it does well and be sceptical of a close-looking result.

The context gap is the largest single difference on this pair: Gemini 3.1 Pro takes 1.0M tokens against 200K for Claude 3.5 Sonnet, roughly 5.2x. That is the difference between feeding in a whole repository or a full contract set and having to chunk it. If your work involves documents you cannot split cleanly, this decides it on its own.

Throughput is close enough to ignore — 95/100 versus 82/100. Neither model will feel noticeably quicker in an interactive product, so latency is not a reason to choose between them.

Gemini 3.1 Pro wins this comparison outright — cheaper and stronger. Choose Claude 3.5 Sonnet only if it has a specific capability you need; on price and benchmarks it is behind on both.

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	Claude 3.5 Sonnet
List price (input / output)	$2.00 / $12.00	$3.00 / $15.00
Cached input	$0.2010% of the input price	—
Batch API	50% off input and output	—
Long prompts	Over 200K tokens: $4.00 / $18.00	—
Input with 80% cache hits	$0.56	—

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.

Claude also bills cache writes: 1.25× the input price for a 5-minute cache, 2× for one hour.

Gemini also bills cache storage by the hour.

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

Capability scores

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

CategoryGemini 3.1Claude 3.5Winner

Coding

Tied

Reasoning

Tied

Extraction

Tied

Creative

Vision

Gemini 3.1 Pro: 1 wins

Claude 3.5 Sonnet: 1 wins

Speed Score

82/100vs95/100

GeminiClaude

Context Window

1049Kvs200K

GeminiClaude

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
Claude 3.5 Sonnet: $1.32

Business email

One typical email (~200 words)

~270 tokens

Gemini 3.1 Pro: $52.38
Claude 3.5 Sonnet: $89.10

Code file

50-line Python script

~400 tokens

Gemini 3.1 Pro: $77.60
Claude 3.5 Sonnet: $132.00

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 Claude 3.5 Sonnet, 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%

Cheaper

Gemini 3.1 Pro

$145.50/mo

$1,746.00/yr

$2.00/M input$12.00/M output

Claude 3.5 Sonnet

$217.80/mo

$2,613.60/yr

$3.00/M input$15.00/M output

Annual Savings

$867.60 saved per year

Gemini 3.1 Pro cheaper · $72.30/mo

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