Is Claude Sonnet 5 or Grok 4 cheaper in 2026?

Grok 4, for every workload modelled here. On a blended 3:1 basis it costs $6.00 per million tokens against Claude Sonnet 5's $6.00.

Which has the larger context window?

Grok 4, at 256K tokens against 200K. A larger window only helps if you can afford to fill it — the cost of one full-context request is in the table above.

Which is cheaper for output-heavy work like agents?

Grok 4, at $15.00 per million output tokens against $15.00. Reasoning tokens bill as output, so for agentic loops this axis usually decides the invoice regardless of what the input rates look like.

What is not included in these figures?

Batch-processing discounts, fine-tuning, long-context surcharges above a provider's standard tier, and any enterprise agreement. These are published pay-as-you-go list prices, checked against each provider's own pricing page on the date shown.

Claude Sonnet 5 vs Grok 4

Grok 4 is cheaper for every workload modelled here.

List prices checked May 2026

Specifications and rates

Property	Claude Sonnet 5	Grok 4
Input per 1M	$3.00	$3.00
Output per 1M	$15.00	$15.00
Cached input per 1M	$0.300	$0.750
Blended (3:1)	$6.00	$6.00
Context window	200K	256K
Max output	64K	64K
Inputs accepted	text, image	text, image

Source: Anthropic pricing (August 2026) · xAI pricing (May 2026). Published list prices only — committed-use discounts, regional variation, and per-request charges are not included. Not yet independently re-checked against the vendor’s page.

Monthly cost by workload

Identical token volumes through both rate cards. Output-heavy profiles are where the ranking flips.

Workload	Claude Sonnet 5	Grok 4	Cheaper
In-app chat assistantA support or help assistant handling a few thousand conversations a month, with short prompts and short answers.	$135	$135	Claude Sonnet 5saves $0/mo
RAG over documentsRetrieval-augmented answering where each request stuffs several retrieved passages into the prompt, so input dominates.	$1,125	$1,125	Claude Sonnet 5saves $0/mo
Coding agentAn agentic loop that reads files and writes patches, generating heavy output and re-sending large context on every turn.	$2,700	$2,700	Claude Sonnet 5saves $0/mo

What each one is for

Claude Sonnet 5

by Anthropic

The workhorse of the Claude family and the default for production work at volume. Introductory pricing of $2/$10 per million tokens runs to 31 August 2026; the $3/$15 standard rate shown here is what applies after that.

Grok 4

by xAI

xAI's flagship, priced to match Claude Sonnet exactly, with a large context window and live access to posts on X as a differentiator.

Common questions

Is Claude Sonnet 5 or Grok 4 cheaper in 2026?: Grok 4, for every workload modelled here. On a blended 3:1 basis it costs $6.00 per million tokens against Claude Sonnet 5's $6.00.
Which has the larger context window?: Grok 4, at 256K tokens against 200K. A larger window only helps if you can afford to fill it — the cost of one full-context request is in the table above.
Which is cheaper for output-heavy work like agents?: Grok 4, at $15.00 per million output tokens against $15.00. Reasoning tokens bill as output, so for agentic loops this axis usually decides the invoice regardless of what the input rates look like.
What is not included in these figures?: Batch-processing discounts, fine-tuning, long-context surcharges above a provider's standard tier, and any enterprise agreement. These are published pay-as-you-go list prices, checked against each provider's own pricing page on the date shown.