Source-tracked model comparison

Gemini 3.8 Flash vs GPT-6 Astra: which fits a long-context API workload?

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

Direct cost answer: Gemini 3.8 Flash is estimated at $242.25 per month and GPT-6 Astra at $3,230.00 for 150,000 input tokens, 5,000 output tokens, and 2,000 monthly requests. Gemini 3.8 Flash is $2,987.75 lower under these assumptions. This does not identify a quality winner.
Current provider alternativesLong-context researchSources checked 2026-09-03 / 2026-09-08
Tracked facts

Pricing and model limits

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

FieldGemini 3.8 FlashGPT-6 Astra
API access providerGoogleOpenAI
API model IDgemini-3.8-flashgpt-6-astra
Input / 1M$0.75$10.00
Cached input / 1M$0.075$1.00
Output / 1M$3.75$50.00
Context window1,048,576 tokens1,050,000 tokens
Maximum output65,536 tokens128,000 tokens
Accepted inputtext, image, video, audiotext, image
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.

Google

Gemini 3.8 Flash

$242.25 / month
Input cost
$204.75
Output cost
$37.50
Per 1,000 calls
$121.13
Pricing profile
standard
View model details
OpenAI

GPT-6 Astra

$3,230.00 / month
Input cost
$2,730.00
Output cost
$500.00
Per 1,000 calls
$1,615.00
Pricing profile
standard / short context
View model details

Cost result: Gemini 3.8 Flash is $2,987.75 lower per month for these assumptions. This is a price comparison, not a model-quality ranking.

StackLens assessment

Questions to answer before choosing

  • Which model meets the workload's quality threshold?
  • How do output length and the OpenAI long-context boundary change cost?
  • Does limited GPT-6 Astra access affect the deployment decision?
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.