Which is more cost-effective, Gemini 3.1 Pro or Claude Sonnet 5.5?

Based on 1M input + 1M output tokens, Gemini 3.1 Pro costs $14.00/month versus Claude Sonnet 5.5 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. Claude Sonnet 5.5 scores 97 in coding and 94 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 Sonnet 5.5?

Gemini 3.1 Pro supports a 1.0M-token context window while Claude Sonnet 5.5 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 Claude Sonnet 5.5 scores 91/100 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 Sonnet 5.5

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 12, 2026.

Check the source

How we verify prices

Model BAnthropic

Claude Sonnet 5.5

Capability score (editorial)94/100

Cost / 1M Tokens: $4.40; 70% in · 30% out mix; ≈ $6.29 for the same text, tokenizer included
Value Index (score÷cost): 14.9; Higher = better value

Speed: 91/100
Context: 1.0M
Tier: Smart Tier

List price from the Anthropic pricing page, verified October 12, 2026.

Its tokenizer produces about 43% 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.

Check the source

How we verify prices

In-depth analysis

Gemini 3.1 Pro vs Claude Sonnet 5.5: 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 Sonnet 5.5 from Anthropic is a mid-range-tier model supporting 1.0M tokens in context, with standout performance in coding.

This is a genuine tradeoff rather than a clear win. Claude Sonnet 5.5 leads by 14 points on combined coding and reasoning, and costs 23% more for the same text to do it. The margin is narrow enough that the answer depends on your workload: on tasks where the extra capability shows up, the premium pays for itself; on routine work it does not. Gemini 3.1 Pro is priced at $2.00/M input tokens and $12.00/M output tokens. Claude Sonnet 5.5 costs $2.00/M input and $10.00/M output.

Claude Sonnet 5.5 turns the same text into about 47% more tokens than Gemini 3.1 Pro, because their tokenizers differ — so comparing list prices per token understates what Claude Sonnet 5.5 costs. For the same text, split 70% input and 30% output and counted the way OpenAI's tokenizer counts it, Claude Sonnet 5.5 works out at about $6.29 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, Claude Sonnet 5.5 leads with 97/100 for coding and 94/100 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 Claude Sonnet 5.5 stack up head to head:

coding

Claude Sonnet leads

reasoning

Claude Sonnet leads

data extraction

Claude Sonnet leads

creative tasks

Claude Sonnet leads

vision/multimodal

Gemini 3.1 leads

Best model by task

coding: Claude Sonnet 5.5 wins with 97/100
reasoning: Claude Sonnet 5.5 wins with 94/100
data extraction: Claude Sonnet 5.5 wins with 94/100
creative tasks: Claude Sonnet 5.5 wins with 93/100
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 Sonnet 5.5 runs about $57.20 — Gemini 3.1 Pro saves roughly $14.52 (25%) every month.

What actually decides it

Gemini 3.1 Pro and Claude Sonnet 5.5 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.

Claude Sonnet 5.5 and Gemini 3.1 Pro were released within 7 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 — 91/100 versus 82/100. Neither model will feel noticeably quicker in an interactive product, so latency is not a reason to choose between them.

Neither model is the obvious answer. Claude Sonnet 5.5 leads on benchmarks, Gemini 3.1 Pro on cost, and the gap is small on both. Run the calculator above with your real token mix — for most workloads that decides it faster than any benchmark table will.

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 Sonnet 5.5
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 1M window
Input with 80% cache hits	$0.56	$0.48

With 80% of input served from the cache, Gemini 3.1 Pro costs 21% less than Claude Sonnet 5.5 for the same input text, counting each model's tokenizer.The tokenizer factor for Gemini 3.1 Pro, Claude Sonnet 5.5 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.

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 SonnetWinner

Coding

Reasoning

Extraction

Creative

Vision

Gemini 3.1 Pro: 1 wins

Claude Sonnet 5.5: 4 wins

Claude Sonnet 5.5 leads overall

Speed Score

82/100vs91/100

GeminiClaude

Context Window

1049Kvs1000K

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 Sonnet 5.5: $1.14

Business email

One typical email (~200 words)

~270 tokens

Gemini 3.1 Pro: $52.38
Claude Sonnet 5.5: $77.22

Code file

50-line Python script

~400 tokens

Gemini 3.1 Pro: $77.60
Claude Sonnet 5.5: $114.40

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 Sonnet 5.5, 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 Sonnet 5.5

$188.76/mo

$2,265.12/yr

$2.00/M input$10.00/M output

Annual Savings

$519.12 saved per year

Gemini 3.1 Pro cheaper · $43.26/mo

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