Which is more cost-effective, GPT-5.6 Sol or Gemini 3.1 Pro?

Based on 1M input + 1M output tokens, GPT-5.6 Sol costs $24.00/month versus Gemini 3.1 Pro at $14.00/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?

GPT-5.6 Sol scores 97 in coding and 99 in reasoning benchmarks. Gemini 3.1 Pro 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 GPT-5.6 Sol and Gemini 3.1 Pro?

GPT-5.6 Sol supports a 1.1M-token context window while Gemini 3.1 Pro 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?

GPT-5.6 Sol has a speed score of 70/100 and Gemini 3.1 Pro scores 82/100 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

GPT-5.6 Sol vs Gemini 3.1 Pro

Model AOpenAI

GPT-5.6 Sol

Capability score (editorial)99/100

Cost / 1M Tokens: $8.80; 70% in · 30% out mix
Value Index (score÷cost): 11.2; Higher = better value

Speed: 70/100
Context: 1.1M
Tier: Power Tier

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

Promotional price, guaranteed until at least November 21, 2026. Regular price: $5.00 / $30.00.

Check the source

How we verify prices

Model BGoogle

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

In-depth analysis

GPT-5.6 Sol vs Gemini 3.1 Pro: Detailed Comparison

GPT-5.6 Sol is OpenAI's flagship-tier language model with a 1.1M-token context window, excelling at reasoning. Gemini 3.1 Pro from Google is a mid-range-tier model supporting 1.0M tokens in context, with standout performance in vision/multimodal.

This is a genuine tradeoff rather than a clear win. GPT-5.6 Sol leads by 19 points on combined coding and reasoning, and costs 45% 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. GPT-5.6 Sol is priced at $4.00/M input tokens and $20.00/M output tokens. Gemini 3.1 Pro costs $2.00/M input and $12.00/M output.

On iOPTERA's editorial scores, GPT-5.6 Sol leads with 97/100 for coding and 99/100 for reasoning, against Gemini 3.1 Pro's 88/100 and 89/100.

Capability breakdown

Across the five core benchmark categories, here is how GPT-5.6 Sol and Gemini 3.1 Pro stack up head to head:

coding

GPT-5.6 Sol leads

reasoning

GPT-5.6 Sol leads

data extraction

GPT-5.6 Sol leads

creative tasks

GPT-5.6 Sol leads

vision/multimodal

GPT-5.6 Sol leads

Best model by task

coding: GPT-5.6 Sol wins with 97/100
reasoning: GPT-5.6 Sol wins with 99/100
data extraction: GPT-5.6 Sol wins with 95/100
creative tasks: GPT-5.6 Sol wins with 96/100
vision/multimodal: GPT-5.6 Sol wins with 96/100

Estimated monthly cost at scale

For 10M + 2M tokens of text a month (counted the way OpenAI's tokenizer counts), GPT-5.6 Sol runs about $80.00 while Gemini 3.1 Pro runs about $42.68 — Gemini 3.1 Pro saves roughly $37.32 (47%) every month.

What actually decides it

GPT-5.6 Sol and Gemini 3.1 Pro 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.

GPT-5.6 Sol and Gemini 3.1 Pro were released within 5 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: 1.1M 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.

Neither model is the obvious answer. GPT-5.6 Sol 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	GPT-5.6 Sol	Gemini 3.1 Pro
List price (input / output)	$4.00 / $20.00	$2.00 / $12.00
Cached input	$0.4010% of the input price	$0.2010% of the input price
Batch API	50% off input and output	50% off input and output
Long prompts	Over 272K tokens: $8.00 / $30.00	Over 200K tokens: $4.00 / $18.00
Input with 80% cache hits	$1.12	$0.56

With 80% of input served from the cache, Gemini 3.1 Pro costs 52% less than GPT-5.6 Sol for the same input text, counting each model's tokenizer.The tokenizer factor for Gemini 3.1 Pro 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 OpenAI, Google.

Capability scores

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

CategoryGPT-5.6 SolGemini 3.1Winner

Coding

Reasoning

Extraction

Creative

Vision

GPT-5.6 Sol: 5 wins

Gemini 3.1 Pro: 0 wins

GPT-5.6 Sol leads overall

Speed Score

70/100vs82/100

GPT-5.6Gemini

Context Window

1050Kvs1049K

GPT-5.6Gemini

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

GPT-5.6 Sol: $1.60
Gemini 3.1 Pro: $0.78

Business email

One typical email (~200 words)

~270 tokens

GPT-5.6 Sol: $108.00
Gemini 3.1 Pro: $52.38

Code file

50-line Python script

~400 tokens

GPT-5.6 Sol: $160.00
Gemini 3.1 Pro: $77.60

Prices shown are for 100,000 runs of each workload — one run costs a fraction of a cent on both GPT-5.6 Sol and Gemini 3.1 Pro, 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%

GPT-5.6 Sol

$264.00/mo

$3,168.00/yr

$4.00/M input$20.00/M output

Cheaper

Gemini 3.1 Pro

$145.50/mo

$1,746.00/yr

$2.00/M input$12.00/M output

Annual Savings

$1,422.00 saved per year

Gemini 3.1 Pro cheaper · $118.50/mo

Related Comparisons

Explore similar model pairs to find your best fit

GPT-5.6 SolvsClaude Fable

$4.00 · $10.00/M input

GPT-5.6 SolvsClaude Opus

$4.00 · $5.00/M input

GPT-5.6 SolvsClaude Opus

$4.00 · $5.00/M input

GPT-5.6 SolvsClaude Opus

$4.00 · $5.00/M input

GPT-5.6 SolvsGPT-5.6 Terra

$4.00 · $2.00/M input

GPT-5.6 SolvsGrok 4.5

$4.00 · $2.00/M input

Gemini 3.1vsClaude Opus

$2.00 · $5.00/M input

Gemini 3.1vsGPT-5.6 Terra

$2.00 · $2.00/M input