Source-tracked model comparison

Claude Sonnet 5 vs Gemini 3.1 Pro Preview: how do long-context costs compare?

Compare verified pricing and model limits for current premium models for long-context research. The cost example uses a long-context research workload and does not assume equal model quality.

Direct cost answer: Claude Sonnet 5 is estimated at $646.00 per month and Gemini 3.1 Pro Preview at $666.00 for 150,000 input tokens, 5,000 output tokens, and 2,000 monthly requests. Claude Sonnet 5 is $20.00 lower under these assumptions. This does not identify a quality winner.
Current provider alternativesLong-context researchSources checked 2026-07-12 / 2026-07-14
Tracked facts

Pricing and model limits

Prices are USD per 1M tokens under each model's verified default profile.

FieldClaude Sonnet 5Gemini 3.1 Pro Preview
ProviderAnthropicGoogle
API model IDclaude-sonnet-5gemini-3.1-pro-preview
Input / 1M$2.00$2.00
Cached input / 1M$0.20$0.20
Output / 1M$10.00$12.00
Context window1,000,000 tokens1,048,576 tokens
Maximum output128,000 tokens65,536 tokens
Accepted inputtext, imagetext
Example workload

Long-context research cost scenario

150,000 input and 5,000 output tokens per request, 2,000 monthly requests, and 10% cached input.

Anthropic

Claude Sonnet 5

$646.00 / month
Input cost
$546.00
Output cost
$100.00
Per 1,000 calls
$323.00
Pricing profile
standard
View model details
Google

Gemini 3.1 Pro Preview

$666.00 / month
Input cost
$546.00
Output cost
$120.00
Per 1,000 calls
$333.00
Pricing profile
standard
View model details

Cost result: Claude Sonnet 5 is $20.00 lower per month for these assumptions. This is a price comparison, not a model-quality ranking.

StackLens assessment

Questions to answer before choosing

  • Does the full research packet fit each context limit?
  • How will citation quality be evaluated?
  • Does preview status change the acceptable rollout plan?
Workload caveat

What this estimate leaves out

Models whose tracked context window is below the scenario input are excluded from the compatible-model table.

Latency, reliability, output quality, retries, regional processing, and provider-specific tool charges can change the practical decision.