Gemini 3.1 Pro
gemini-3-1-pro
70% in · 30% out mix
Higher = better value
Speed
82/100
Context
2.0M
Tier
smart
Claude 3.5 Sonnet
claude-3-5-sonnet
70% in · 30% out mix
Higher = better value
Speed
95/100
Context
200K
Tier
smart
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 2.0M-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 coding.
This is a genuine tradeoff rather than a clear win. Claude 3.5 Sonnet leads by 12 points on combined coding and reasoning, and charges 24% more per blended million tokens 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 3.5 Sonnet costs $3.00/M input and $15.00/M output.
In independent benchmark evaluations, Claude 3.5 Sonnet leads with coding scores of 96/100 and reasoning scores of 93/100, compared to Gemini 3.1 Pro's 88/100 in coding and 89/100 in reasoning.
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:
Best model by task
- coding: Claude 3.5 Sonnet wins with 96/100
- reasoning: Claude 3.5 Sonnet wins with 93/100
- 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
At 10M + 2M per month, Gemini 3.1 Pro runs about $44.00 while Claude 3.5 Sonnet runs about $60.00 — Gemini 3.1 Pro saves roughly $16.00 (27%) 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 22 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 2.0M tokens against 200K for Claude 3.5 Sonnet, roughly 10.0x. 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.
One practical asymmetry: Claude 3.5 Sonnet offers a batch API at 50% off standard rates, and Gemini 3.1 Pro does not. For anything that does not need an answer immediately — nightly enrichment, backfills, evaluation runs — that discount can be worth more than the difference in list price, and it is easy to overlook when comparing headline rates.
Neither model is the obvious answer. Claude 3.5 Sonnet 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.
Benchmark Comparison
Head-to-head scores across 5 categories — sourced from official evals
Coding
Reasoning
Extraction
Creative
Vision
Speed Score
Context Window
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!"
- Gemini 3.1 Pro
- $0.78
- Claude 3.5 Sonnet
- $1.26
Business email
One typical email (~200 words)
- Gemini 3.1 Pro
- $52.38
- Claude 3.5 Sonnet
- $85.05
Code file
50-line Python script
- Gemini 3.1 Pro
- $77.60
- Claude 3.5 Sonnet
- $126.00
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_tokensEvery 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
Gemini 3.1 Pro
$150.00/mo
$1,800.00/yr
Claude 3.5 Sonnet
$198.00/mo
$2,376.00/yr
Annual Savings
$576.00 saved per year
Gemini 3.1 Pro cheaper · $48.00/mo
Deep-Dive Audit — Gemini 3.1 Pro & Claude 3.5 Sonnet
Surgically Auditing: Deep Logic
3-YEAR STRATEGIC LOSS PROJECTION
$415.404
Without optimization protocols, current model choices will result in $138.468 capital loss per year.
EFFICIENCY SCORE
89%
This model achieves a 89 benchmark score in this category.
CATEGORY GAP
11 pts
Distance from Leader
Competitive Landscape Analysis
Source: MMLU-Pro + GPQA Diamond (Apr 2026)
Category Champion: Claude Fable 5
According to MMLU-Pro + GPQA Diamond (Apr 2026) data, Claude Fable 5 provides the optimum balance for Deep Logic tasks.
Market Score
%100
Savings Rate
%82
Operational Prescription
- Implement model cascading to optimize token spend.
- Analyze complex_reasoning data to leverage local semantic caching.
COST AUDIT PROTOCOL
Overkill Detected
"Gemini 3.1 Pro is overpriced for this task type. Claude Fable 5 scores 100 in this category at a fraction of the cost."
Categorical Alternative Opportunity
"Claude Fable 5 leads this category with 100 points according to MMLU-Pro + GPQA Diamond (Apr 2026) data."
Inertia Tax Detected
"85% of traffic can be routed to cheaper models. Fast tier (GPT-5 Nano) and Smart tier (o3-mini) can save $11.54/month."
3-Tier Intelligent Routing Architecture
82% SAVINGS VIA ROUTINGGPT-5 Nano
IQ Score: 72/100
$18.00/yr
o3-mini
IQ Score: 97/100
$277.20/yr
DeepSeek R1
IQ Score: 97/100
$59.184/yr
Without tiered routing, you pay the 'Inertia Tax' — routing all traffic to the most expensive model regardless of task complexity. Tiered cascade eliminates $1,661.616/year in avoidable overhead.
Deep Logic — Model Cost / Quality Matrix
Source: MMLU-Pro + GPQA Diamond (Apr 2026)| Model | Benchmark | Input (per M) | Output (per M) | Annual Cost* | Value Index |
|---|---|---|---|---|---|
o3-miniBEST VALUE | 97/100 | $1.10 | $4.40 | $66.00 | 100/100 |
GPT-5.2 Chat | 96/100 | $1.75 | $14.00 | $189.00 | 35/100 |
Claude 3.7 Sonnet | 95/100 | $3.00 | $15.00 | $216.00 | 30/100 |
GPT-5.6 Terra | 94/100 | $2.00 | $12.00 | $168.00 | 38/100 |
Claude 3.5 Sonnet | 93/100 | $3.00 | $15.00 | $216.00 | 29/100 |
GPT-4.1 | 93/100 | $2.00 | $8.00 | $120.00 | 53/100 |
Claude Sonnet 5 | 92/100 | $3.00 | $15.00 | $216.00 | 29/100 |
Grok 4.5 | 90/100 | $2.00 | $6.00 | $96.00 | 64/100 |
GPT-4o | 90/100 | $2.50 | $10.00 | $150.00 | 41/100 |
Gemini 3.1 ProSELECTED | 89/100 | $2.00 | $12.00 | $168.00 | 36/100 |
Gemini 2.0 Pro | 88/100 | $1.25 | $5.00 | $75.00 | 80/100 |
Gemini 1.5 Pro | 87/100 | $1.25 | $5.00 | $75.00 | 79/100 |
Mistral Large 2 | 86/100 | $2.00 | $6.00 | $96.00 | 61/100 |
* Annual cost for given volumes. Value Index = Score / Cost (Higher = Best Value).
// iOPTERA Surgical Routing Wrapper
const auditModel = async (prompt: string) => {
const complexity = measureComplexity(prompt);
// Tactical Cascade Logic
if (complexity < 0.45) {
// Redirect simple tasks to efficient model
return await llm.call("iOPTERA Optimization", prompt);
}
// High-latency routing for complex reasoning
return await llm.call("Claude Fable 5", prompt);
};Related Comparisons
Explore similar model pairs to find your best fit