Head-to-head comparison

GPT-6 Astra vs. Gemini 3.8 Flash

Compare published benchmark results from matching versions and cohorts, API pricing, and technical specifications. Any documented test setup differences remain visible.

shared result series: 22
distinct benchmarks: 22
latest retrieval: 2026-09-29

First modelSecond model

Specifications

General specifications

Release date, availability, context window, architecture, and published parameter counts at a glance. Undisclosed details remain marked as unavailable.

Specifications for GPT-6 Astra and Gemini 3.8 Flash
Attribute	GPT-6 Astra	Gemini 3.8 Flash
Provider	OpenAI	Google
Released	Sep 3, 2026	Sep 2, 2026
Availability	Limited access	Active
Model type	Proprietary	Proprietary
Parameters	Not published	Not published
Architecture	Not published	Not published
Context window	1,050,000 tokens	1,048,576 tokens
Knowledge cutoff	April 30, 2026	March 2026
Technical sources	Model, Context	Model, Knowledge cutoff

Pricing

API pricing compared

The table compares official standard API rates per 1M tokens, including published cache pricing. Batch, fast, priority, regional surcharges, tool calls, and cloud platform pricing are excluded.

API pricing for GPT-6 Astra and Gemini 3.8 Flash
Price type	GPT-6 Astra	Gemini 3.8 Flash
API input	$10 ≤272K / $20 >272K	$0.75
API output	$50 ≤272K / $75 >272K	$3.75
Cache read	$1 ≤272K / $2 >272K	$0.075
Cache write (5 min.)	$12.5 ≤272K / $25 >272K	Not listed
Cache write (1 hr.)	Not listed	Not listed
Price verified	09/22/2026 Source	09/22/2026 Source

GPT-6 AstraGemini 3.8 Flash

API inputUSD per 1M tokens, base tier

GPT-6 Astra$10

Gemini 3.8 Flash$0.75

API outputUSD per 1M tokens, base tier

GPT-6 Astra$50

Gemini 3.8 Flash$3.75

Cache readUSD per 1M tokens, base tier

GPT-6 Astra$1

Gemini 3.8 Flash$0.075

Key to the marks:better valuebetter, but not conclusivetie

Pricing by provider

Direct developer pricing and provider endpoint tariffs routed through OpenRouter are listed separately. Prices are in USD per 1M tokens. Context-dependent direct tiers plus regional, Flex, Priority, and other OpenRouter tariffs remain individually identifiable.

Provider pricing for GPT-6 Astra and Gemini 3.8 Flash
Model	Provider	Purchase route and tariff	Input per 1M tokens	Output per 1M tokens	Source
GPT-6 Astra	OpenAI	Direct from developerUp to 272,000 context tokens	$10	$50	Source09/22/2026
	OpenAI	Direct from developerAbove 272,000 context tokens	$20	$75	Source09/22/2026
	Amazon Bedrock	Via OpenRouteramazon-bedrock/us-west-2	$11	$55	Source10/14/2026
	Azure	Via OpenRouterazure	$10	$50	Source10/14/2026
	Azure	Via OpenRouterazure/us	$11	$55	Source10/14/2026
	OpenAI	Via OpenRouteropenai	$10	$50	Source10/14/2026
	OpenAI	Via OpenRouteropenai/fast	$20	$100	Source10/14/2026
	OpenAI	Via OpenRouteropenai/flex	Lowest listed price: $5	Lowest listed price: $25	Source10/14/2026
	OpenAI	Via OpenRouteropenai/ultrafast	$60	$300	Source10/14/2026
Gemini 3.8 Flash	Google	Direct from developerStandard API	$0.75	$3.75	Source09/22/2026
	Google	Via OpenRoutergoogle-vertex/global	$0.75	$3.75	Source10/14/2026
	Google	Via OpenRoutergoogle-vertex/global/flex	Lowest listed price: $0.375	Lowest listed price: $1.875	Source10/14/2026
	Google	Via OpenRoutergoogle-vertex/global/priority	$1.35	$6.75	Source10/14/2026
	Google AI Studio	Via OpenRoutergoogle-ai-studio	$0.75	$3.75	Source10/14/2026
	Google AI Studio	Via OpenRoutergoogle-ai-studio/flex	Lowest listed price: $0.375	Lowest listed price: $1.875	Source10/14/2026
	Google AI Studio	Via OpenRoutergoogle-ai-studio/priority	$1.35	$6.75	Source10/14/2026

Performance

Shared benchmarks

Only published results with the same benchmark version, task, metric, and comparison cohort are paired. Different reasoning levels, agents, harnesses, or output limits appear directly in the table.

Capability profile from matched benchmarks

Each axis averages directly matched benchmark families. A value of 100 means the stronger value within this pair, not a universal quality score.

GPT-6 Astra

Gemini 3.8 Flash

Coding: 100 / 51.3 (6 benchmark families)

Mathematics: 100 / 48.5 (1 benchmark family)

Finance: 93.8 / 100 (3 benchmark families)

Legal: 77.1 / 99.4 (2 benchmark families)

Agentic tasks: 100 / 57 (2 benchmark families)

Cybersecurity: 93.9 / 100 (1 benchmark family)

Health: 100 / 97.7 (2 benchmark families)

Education: 100 / 75.6 (1 benchmark family)

22 matched rows from 21 benchmark families were considered. The radar shows 8 of 10 comparable categories.

GPT-6 AstraGemini 3.8 Flash

BioMysteryBenchOverall. Higher is better. No documented setup difference

GPT-6 Astra79.259 %

Gemini 3.8 Flash62.222 %

Code MigrationOverall. Higher is better. No documented setup difference

GPT-6 Astra67.74 %

Gemini 3.8 Flash36.546 %

CyberBench v1.1Overall. Higher is better. No documented setup difference

GPT-6 Astra41.072 %

Gemini 3.8 Flash43.75 %

EMBOverall. Higher is better. No documented setup difference

GPT-6 Astra71.7 %

Gemini 3.8 Flash72.196 %

Finance Agent (v2)Overall. Higher is better. No documented setup difference

GPT-6 Astra53.54 %

Gemini 3.8 Flash61.435 %

Harvey's Legal Agent BenchmarkOverall · Task fully resolved. Higher is better. No documented setup difference

GPT-6 Astra5.417 %

Gemini 3.8 Flash10 %

IOIOverall. Higher is better. No documented setup difference

GPT-6 Astra100 %

Gemini 3.8 Flash56.944 %

Legal Research BenchOverall · All-pass. Higher is better. No documented setup difference

GPT-6 Astra39.423 %

Gemini 3.8 Flash38.942 %

MedCodeOverall. Higher is better. No documented setup difference

GPT-6 Astra48.486 %

Gemini 3.8 Flash48.135 %

MedScribeOverall. Higher is better. No documented setup difference

GPT-6 Astra87.908 %

Gemini 3.8 Flash84.496 %

MysteryMechanismOverall. Higher is better. No documented setup difference

GPT-6 Astra53.153 %

Gemini 3.8 Flash36.486 %

ProgramBenchOverall. Higher is better. No documented setup difference

GPT-6 Astra5.5 %

Gemini 3.8 Flash1 %

Key to the marks:better valuebetter, but not conclusivetie

Benchmark scores for GPT-6 Astra and Gemini 3.8 Flash
Benchmark and task	GPT-6 Astra	Gemini 3.8 Flash	Source
BioMysteryBenchOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is betterSettings: Harness: Terminus 2	Winner79.259 %	62.222 %	Vals AI Source details Data as of: 09/27/2026
Code MigrationOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner67.74 %	36.546 %	Vals AI Source details Data as of: 09/27/2026
CyberBench v1.1Overall Test details No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is better	41.072 %	Winner43.75 %	Vals AI Source details Data as of: 09/27/2026
EMBOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	71.7 %	Winner72.196 %	Vals AI Source details Data as of: 09/27/2026
Finance Agent (v2)Overall Test details No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better	53.54 %	Winner61.435 %	Vals AI Source details Data as of: 09/27/2026
Harvey's Legal Agent BenchmarkOverall · Task fully resolved Test details No documented difference in the test setupVersion: 1Metric: task resolution rateScoring: Higher is better	5.417 %	Winner10 %	Vals AI Source details Data as of: 09/27/2026
IOIOverall Test details No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better	Winner100 %	56.944 %	Vals AI Source details Data as of: 09/27/2026
Legal Research BenchOverall · All-pass Test details No documented difference in the test setupVersion: 1Metric: all-pass rateScoring: Higher is better	Winner39.423 %	38.942 %	Vals AI Source details Data as of: 09/27/2026
MedCodeOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner48.486 %	48.135 %	Vals AI Source details Data as of: 09/26/2026
MedScribeOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner87.908 %	84.496 %	Vals AI Source details Data as of: 09/26/2026
MysteryMechanismOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner53.153 %	36.486 %	Vals AI Source details Data as of: 09/27/2026
ProgramBenchOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner5.5 %	1 %	Vals AI Source details Data as of: 09/27/2026
ProofBenchOverall Test details No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is better	Winner99 %	48 %	Vals AI Source details Data as of: 09/28/2026
SAGEOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner46.367 %	35.064 %	Vals AI Source details Data as of: 09/26/2026
Tax Agent BenchOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	63.335 %	Winner66.771 %	Vals AI Source details Data as of: 09/27/2026
Terminal-Bench 2.1Overall Test details No documented difference in the test setupVersion: 2.1Metric: accuracyScoring: Higher is better	Winner87.266 %	81.273 %	Vals AI Source details Data as of: 09/27/2026
Terminal-Bench 4.0Overall Test details No documented difference in the test setupVersion: 4.0Metric: accuracyScoring: Higher is better	Winner57.071 %	13.131 %	Vals AI Source details Data as of: 09/27/2026
Terminal-Bench ScienceOverall Test details No documented difference in the test setupVersion: 0.1Metric: accuracyScoring: Higher is better	Winner65.714 %	8.571 %	Vals AI Source details Data as of: 09/27/2026
Time Horizon Index: KSPOverall Test details No documented difference in the test setupVersion: 1Metric: progressScoring: Higher is better	Winner90.5 %	18.833 %	Vals AI Source details Data as of: 09/14/2026
Vals IndexOverall Test details No documented difference in the test setupVersion: 2Metric: weighted index scoreScoring: Higher is better	Winner66.608 %	62.252 %	Vals AI Source details Data as of: 09/27/2026
Vibe Code Bench 1-100Overall Test details No documented difference in the test setupVersion: 1.0Metric: accuracyScoring: Higher is betterSettings: Harness: OpenHands	Winner27.644 %	18.772 %	Vals AI Source details Data as of: 09/22/2026
Vibe Code Bench v1.1Overall Test details No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is betterSettings: Harness: OpenHands	Winner89.594 %	78.651 %	Vals AI Source details Data as of: 09/27/2026
Key to the marks:better valuebetter, but not conclusivetie

Our model tests

Our tests

SVG short test

One SVG prompt and fixed output settings. Captures are shown only with 0 reported reasoning tokens or documented lack of reasoning controls. Identical test conditions do not make the models' internal compute identical.

Shared test round: 4ae5d8eeb9a9

GPT-6 Astra

Unavailable in this round

Gemini 3.8 Flash

Unavailable in this round

Earlier tests

Pelican on a bicycle

A community classic for free-form SVG drawing.

GPT-6 Astra

Reasoning (requested): high

Current attempt

Run date: Sep 7, 2026
API provider: openrouter
Requested API model: openai/gpt-6-astra
API model reported in response: openai/gpt-6-astra
Reasoning setting: high
Pinned endpoint: OpenAI | openai/gpt-6-astra-20260903
Temperature: Provider default
Token limit including reasoning: 8,192 tokens
Test protocol: community-visual-tests-v1
Technical checks: Passed, not a quality rating
Response time: 141.7 s

Visually reviewed. This individual test does not establish overall model quality.

Gemini 3.8 Flash

The response reached the token limit. No complete recording is available.

Reasoning (requested): high

Current attempt

Run date: Oct 5, 2026
API provider: openrouter
Requested API model: google/gemini-3.8-flash
API model reported in response: google/gemini-3.8-flash
Reasoning setting: high
Pinned endpoint: Google AI Studio | google/gemini-3.8-flash-20260902
Temperature: Provider default
Token limit including reasoning: 8,192 tokens
Test protocol: community-visual-tests-v1
Technical checks: Failed
Response time: 40.2 s

Not yet visually reviewed. A successful recording does not confirm correct physics or full compliance with the prompt.

Earlier attempts (3)

Oct 2, 2026API request failedReasoning setting: high
Oct 1, 2026API request failedReasoning setting: high
Sep 7, 2026API request failedReasoning setting: high

Prompt and test conditions

Generate an SVG of a pelican riding a bicycle

Token limit including reasoning: 8,192 tokens

Task origin (Simon Willison)

How to read this comparison

Winning one benchmark is not an overall verdict

Your workload, budget, and required context length matter most. A coding benchmark says little about visual understanding or agent performance.

The standard price table uses direct developer rates. The provider comparison labels OpenRouter endpoints, regions, and special tariffs separately.

Every result links to its measurement source and retrieval date. Labels distinguish vendor reports, official benchmark leaderboards, and independent evaluations. Disputed or archived results are excluded.

More matchups

Compare GPT-6 Astra and Gemini 3.8 Flash with other leading models using the same data and benchmark logic.

View the complete LLM comparison

GPT-6 Astra vs. Gemini 3.8 Flash

Change model selection

General specifications

API pricing compared

Shared benchmarks

Capability profile from matched benchmarks

Our tests

SVG short test

GPT-6 Astra

Gemini 3.8 Flash

Pelican on a bicycle

Winning one benchmark is not an overall verdict

Related LLM comparisons