Head-to-head comparison

GPT-6 Astra vs. Grok 4.3

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

shared result series: 11
distinct benchmarks: 11
latest retrieval: 2026-09-04

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 Grok 4.3
Attribute	GPT-6 Astra	Grok 4.3
Provider	OpenAI	xAI
Released	Sep 3, 2026	May 6, 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	1,000,000 tokens
Knowledge cutoff	April 30, 2026	Not published
Technical sources	Model, Context	Model

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 Grok 4.3
Price type	GPT-6 Astra	Grok 4.3
API input	$10 ≤272K / $20 >272K	$1.25 ≤200K / $2.5 >200K
API output	$50 ≤272K / $75 >272K	$2.5 ≤200K / $5 >200K
Cache read	$1 ≤272K / $2 >272K	$0.2 ≤200K / $0.4 >200K
Cache write (5 min.)	$12.5 ≤272K / $25 >272K	Not listed
Cache write (1 hr.)	Not listed	Not listed
Price verified	09/04/2026 Source	08/11/2026 Source

GPT-6 AstraGrok 4.3

API inputUSD per 1M tokens, base tier

GPT-6 Astra$10

Grok 4.3$1.25

API outputUSD per 1M tokens, base tier

GPT-6 Astra$50

Grok 4.3$2.5

Cache readUSD per 1M tokens, base tier

GPT-6 Astra$1

Grok 4.3$0.2

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.

No provider tariff for GPT-6 Astra is available in the stored OpenRouter snapshot. The official direct price is still shown.

Provider pricing for GPT-6 Astra and Grok 4.3
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	Lowest listed price: $10	Lowest listed price: $50	Source09/04/2026
GPT-6 Astra	OpenAI	Direct from developerAbove 272,000 context tokens	$20	$75	Source09/04/2026
Grok 4.3	xAI	Direct from developerUp to 200,000 context tokens	Lowest listed price: $1.25	Lowest listed price: $2.5	Source08/11/2026
	xAI	Direct from developerAbove 200,000 context tokens	$2.5	$5	Source08/11/2026
	xAI	Via OpenRouterxai	Lowest listed price: $1.25	Lowest listed price: $2.5	Source09/04/2026
	xAI	Via OpenRouterxai/priority	$2.5	$5	Source09/04/2026
	xAI	Via OpenRouterxai/zdr	Lowest listed price: $1.25	Lowest listed price: $2.5	Source09/04/2026
	xAI	Via OpenRouterxai/zdr/priority	$2.5	$5	Source09/04/2026

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

Grok 4.3

Coding: 100 / 15.8 (2 benchmark families)

Finance: 100 / 48.1 (2 benchmark families)

Legal: 100 / 23.4 (2 benchmark families)

Agentic tasks: 100 / 48.1 (1 benchmark family)

Health: 100 / 81.6 (2 benchmark families)

Education: 100 / 42.6 (1 benchmark family)

Overall: 100 / 36.5 (1 benchmark family)

11 matched rows from 11 benchmark families were considered. The radar shows 7 of 7 comparable categories.

GPT-6 AstraGrok 4.3

Code MigrationOverall. Higher is better. No documented setup difference

GPT-6 Astra67.74 %

Grok 4.36.795 %

EMBOverall. Higher is better. No documented setup difference

GPT-6 Astra71.7 %

Grok 4.318.394 %

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

GPT-6 Astra53.54 %

Grok 4.337.728 %

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

GPT-6 Astra5.417 %

Grok 4.30.417 %

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

GPT-6 Astra39.423 %

Grok 4.315.385 %

MedCodeOverall. Higher is better. No documented setup difference

GPT-6 Astra48.486 %

Grok 4.338.068 %

MedScribeOverall. Higher is better. No documented setup difference

GPT-6 Astra87.908 %

Grok 4.374.399 %

SAGEOverall. Higher is better. No documented setup difference

GPT-6 Astra46.367 %

Grok 4.319.736 %

Terminal-Bench 2.1Overall. Higher is better. No documented setup difference

GPT-6 Astra87.266 %

Grok 4.341.948 %

Vals IndexOverall. Higher is better. No documented setup difference

GPT-6 Astra66.608 %

Grok 4.324.294 %

Vibe Code Bench v1.1Overall. Higher is better. No documented setup difference

GPT-6 Astra89.594 %

Grok 4.319.403 %

Key to the marks:better valuebetter, but not conclusivetie

Benchmark scores for GPT-6 Astra and Grok 4.3
Benchmark and task	GPT-6 Astra	Grok 4.3	Source
Code MigrationOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner67.74 %	6.795 %	Vals AI Source details Data as of: 09/03/2026
EMBOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner71.7 %	18.394 %	Vals AI Source details Data as of: 09/03/2026
Finance Agent (v2)Overall Test details No documented difference in the test setupVersion: 2Metric: accuracyScoring: Higher is better	Winner53.54 %	37.728 %	Vals AI Source details Data as of: 09/03/2026
Harvey's Legal Agent BenchmarkOverall · Task fully resolved Test details No documented difference in the test setupVersion: 1Metric: task resolution rateScoring: Higher is better	Winner5.417 %	0.417 %	Vals AI Source details Data as of: 09/03/2026
Legal Research BenchOverall · All-pass Test details No documented difference in the test setupVersion: 1Metric: all-pass rateScoring: Higher is better	Winner39.423 %	15.385 %	Vals AI Source details Data as of: 09/03/2026
MedCodeOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner48.486 %	38.068 %	Vals AI Source details Data as of: 09/03/2026
MedScribeOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner87.908 %	74.399 %	Vals AI Source details Data as of: 09/03/2026
SAGEOverall Test details No documented difference in the test setupVersion: 1Metric: accuracyScoring: Higher is better	Winner46.367 %	19.736 %	Vals AI Source details Data as of: 09/03/2026
Terminal-Bench 2.1Overall Test details No documented difference in the test setupVersion: 2.1Metric: accuracyScoring: Higher is better	Winner87.266 %	41.948 %	Vals AI Source details Data as of: 09/03/2026
Vals IndexOverall Test details No documented difference in the test setupVersion: 2Metric: weighted index scoreScoring: Higher is better	Winner66.608 %	24.294 %	Vals AI Source details Data as of: 09/03/2026
Vibe Code Bench v1.1Overall Test details No documented difference in the test setupVersion: 1.1Metric: accuracyScoring: Higher is betterSettings: Harness: OpenHands	Winner89.594 %	19.403 %	Vals AI Source details Data as of: 09/03/2026
Key to the marks:better valuebetter, but not conclusivetie

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

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View the complete LLM comparison