Grok 4.6: Release Date and What Changed (August 2026)

xAI shipped Grok 4.6 on August 12, 2026, roughly five weeks after Grok 4.5. The API model id is simply grok-4.6, and xAI's own framing for the release is that it was built "for long-running agents and more ambitious interactive and visual work."

Note for readers arriving later: as of October 2026, Grok 4.6 is no longer xAI's flagship. The model documentation now reads "For everything else, including code, use Grok 4.7." Everything below still describes the 4.6 release accurately, with every Artificial Analysis figure restated on AA's current Intelligence Index v4.3.2 rather than the v4.1.1 version in use at launch.

The launch-day story was narrow — API, Cursor and Grok Build. The three weeks since have been the more interesting part: the model rolled out across GitHub Copilot, Amazon Bedrock, Google's Model Garden and Microsoft Foundry, and Grok Build went from an invite-shaped tool to a public product on every plan. This page covers the release itself, what actually changed, what the benchmark numbers mean, and where you can use it as of the end of August 2026.

When was Grok 4.6 released?

August 12, 2026. That is the date the model went live on the xAI API and in Cursor and Grok Build simultaneously. But "released" has meant something slightly different every week since, because availability kept expanding. Here is the full dated timeline.

If you were told in mid-August that Grok 4.6 was an API-only, developer-only release, that was true for about 48 hours. By August 21 it was reachable from all three major clouds and from consumer subscription tiers.

What are Grok 4.6's specifications?

xAI has published no architecture details for Grok 4.6 — no parameter count, no mixture-of-experts disclosure, no training compute figure and no system card. Any parameter number you see quoted for this model is third-party inference, not a vendor statement.

Is there a separate "Grok 4.6 High" model?

No, and this trips people up constantly. You will see "Grok 4.6 (high)" and "Grok 4.6 (xhigh)" listed as separate rows on benchmark leaderboards. Those are reasoning_effort settings against one model id, not different SKUs. There is exactly one grok-4.6.

The genuinely new setting is xhigh — "maximum reasoning depth, with correspondingly higher latency." It is the first release where that value does anything: Grok 4.5 accepted the parameter and silently downgraded the request to high. Worth knowing before you reach for it: on Artificial Analysis's Intelligence Index v4.3.2, xhigh scores 44.20 against the default high's 44.31 — a tie within noise, and emphatically not an improvement, for roughly 25% more cost per task ($2.32 against $1.86) and 11 extra seconds to first token. More thinking is not automatically better.

What actually changed in Grok 4.6?

xAI describes Grok 4.6 as a post-training and training-recipe release rather than a new foundation. The changes it names are:

• Longer supplemental training on curated model-generated data aimed at reasoning
• An improved optimizer and training recipe
• Better self-testing and verification on extended, long-horizon tasks
• Stronger visual and interactive work — the "ambitious interactive and visual projects" framing
• The xhigh reasoning level, the one concrete API-surface addition

What did not change: the context window (still 500K), the price list ($2/$6), the modalities (text and image in, text out), and the region footprint. If you are already calling grok-4.5, swapping the model string is the entire migration.

How is Grok 4.6 different from Grok 4.5 in measured terms?

Vendor descriptions are one thing; independent measurement is another. Artificial Analysis has run both models under the same harness, which makes this the cleanest generation-over-generation comparison available.

Two things stand out. The 5.5-point intelligence gain is real and large for a point release. And time to first token roughly doubled — from 14.02 seconds to 27.80. That is the biggest practical regression in the release, and it is a direct consequence of the deeper reasoning the model does before it starts emitting. Throughput once it starts is clearly better than 4.5's: 72.9 tok/s against 59.6.

One correction worth making explicitly, because it propagated widely across coverage of this release (including an earlier version of this page): Grok 4.6 was often reported at a ~44-second first token alongside a throughput only marginally above 4.5. Those two metrics were transposed. Grok 4.6 is clearly faster on output speed and slower to first token than 4.5, and AA's model page reads 27.80s, not 44s.

Note also that cost per finished task rose about 79% — $1.04 to $1.86 per Intelligence Index task — despite an unchanged price list. That is the model spending more reasoning tokens per task. Per-token pricing held; cost per job did not.

For a section-by-section breakdown of the two models, see Grok 4.6 vs Grok 4.5: what changed and should you upgrade.

What do Grok 4.6's benchmark numbers actually say?

Separate these into two buckets, because they are not the same kind of claim.

What xAI reported

These are the figures in xAI's own launch announcement, all for Grok 4.6 at the default high reasoning level Treat them as a dated snapshot — the Intelligence Index figure in particular was measured on v4.1.1, which AA has since replaced with v4.3.2:

What independent evaluators measured

Artificial Analysis confirmed the headline at launch — but the headline has since been restated on a different scale. AA rebased its Intelligence Index from v4.1.1 to v4.3.2, re-scoring every model against a changed benchmark basket. There is no conversion factor between the versions, so xAI's launch figure of 61 and anything on the live board are not comparable numbers.

On Intelligence Index v4.3.2, read 5 October 2026, Grok 4.6 at high scores 44.31 and ranks #36 of 224 models, against a field median of 26. The same capture measures output speed at 72.9 tokens/second, time to first token at 27.80 seconds, and $1.86 per Intelligence Index task, having generated 94M output tokens to complete the suite. AA now also labels grok-4.6 deprecated on its model page and points readers to Grok 4.7; xAI's own catalogue still lists 4.6 with no retirement date.

Arena (the human-preference leaderboard formerly at LMArena) tells a very different story. In its August 27, 2026 snapshot, Grok 4.6 sits at rank 48 with a preliminary score of 1461 ±10, well outside a top ten dominated by Anthropic's Claude family and Meta's Muse Spark. Preliminary scores move as votes accumulate, so treat that as provisional — but the gap between "6th on a benchmark index" and "48th on blind human preference" is too wide to ignore.

The Terminal-Bench version trap

This is the single most misread number in the release. xAI reports 26% on Terminal-Bench v3.0. Most third-party leaderboards still report v2.1, a substantially easier version, where scores in the 70–90% range are normal.

Those are the same model on different exams. Any article, chart or vendor comparison that places a v3.0 figure next to a v2.1 figure is producing nonsense. Always check the version suffix before comparing Terminal-Bench scores across sources. We break the cross-source discrepancies down in detail in Grok 4.6 benchmarks explained.

Where can you actually use Grok 4.6?

As of August 31, 2026, five routes:

• The xAI API — grok-4.6 via console.x.ai. Two regions (us-east-1, us-west-2), 150 requests/second, 50M tokens/minute, no Batch API support.
• The major clouds — generally available on Amazon Bedrock (August 19), Google's Model Garden / Enterprise Agent Platform (August 21) and Microsoft Foundry (August 26). All three list the same $2/$6 headline rate.
• Gateways — OpenRouter, Vercel and Cloudflare were day-one partners.
• Coding tools — Cursor from day one; GitHub Copilot's model picker from August 14, in both VS Code and GitHub workflows.
• xAI's own products — Grok Build, now public on all plans across web and mobile since August 19. Grok Bot, the persistent cloud "AI teammate" product, is available on SuperGrok Plus, SuperGrok Heavy, Cursor Pro+, Cursor Ultra and Cursor Teams since the August 21 expansion.

Grok Build is the surface most people underestimate — the August 19 public release added publishing, custom domains, GitHub export, secrets and connectors, which turns it from a demo into something you can actually ship from. If that is the part you care about, we have a dedicated walkthrough: the xAI Grok Build skills and connectors guide.

The EU gap is still open. Only us-east-1 and us-west-2 are offered on the xAI API. If your data residency requirements rule out US-only inference, the cloud marketplace routes are worth checking before you rule the model out entirely.

What does Grok 4.6 cost?

The short version: $2 per million input tokens and $6 per million output, with cached input at $0.50 — identical to Grok 4.5's list price. Two details that matter more than the headline:

• Crossing 200K prompt tokens doubles the rate on the entire request. Above that threshold it is $4 input / $1 cached / $12 output, applied to every token in the call, not just the ones past the line. A 210K-token prompt is billed at the higher rate across all 210K.
• xAI's x_search tool costs $5 per 1,000 calls — first-party licensed access to X posts, profiles and threads. Nothing else on the market offers it.

That is deliberately a summary. Cache-hit economics, per-task cost against competitors, the long-context threshold maths and worked agent-loop examples all live in our dedicated breakdown: Grok 4.6 pricing and API costs. If cost is the reason you are here, start there instead.

Where does Grok 4.6 sit against the frontier?

Honestly: frontier-adjacent, not frontier-leading, and the answer depends heavily on which measurement you trust.

Here is where it sits on Intelligence Index v4.3.2, read 5 October 2026. Each row names its effort tier, because the tiers differ by more than many models differ from each other. Ranks are shown only for the three Grok entries and the current leader: AA's field is 224 models and reshuffles weekly, so a rank quoted against an older field size is stale even when the score is right.

Read that carefully, because the rebase changed the story. At launch Grok 4.6 looked tied with Claude Opus 5 and GPT-5.6 Sol on a rounded score. On v4.3.2 it is 6.5 points behind Claude Opus 5 (max) and 13.3 behind Claude Opus 5.5 (max), and the Arena result suggests the benchmark placement still flatters it relative to how people rate its answers in blind comparison. "Frontier-adjacent" was the right verdict; it is simply further from the frontier than the old numbers implied.

One thing remains unambiguously in its favour: real-time X data via x_search is not substitutable — for social listening, news monitoring or anything needing live public sentiment, no competitor has licensed firehose access.

The price-to-index argument, though, no longer holds the way it did. GLM 5.3 Flash gets within 2.5 index points for roughly a twelfth of the output rate, at $0.25 per Index task against Grok's $1.86. And grok-4.7 costs the same $2/$6 for a higher ceiling, which makes 4.6 the wrong default even inside xAI's own catalogue — see our Grok 4.7 guide and the Grok 4.7 vs Grok 4.6 comparison.

Two things are still unambiguously against it. The 500K context window is last in class among current frontier models, most of which are at or above 1M — and the 200K billing threshold means you pay double well before you exhaust it. And a 27.8-second time to first token is difficult to build interactive tooling around — slow, though not the ~44 seconds widely reported.

Should you use Grok 4.6?

Yes, if you are already running on it, in batch or background agent work where a ~28-second cold start is irrelevant. That is the remaining case — for a new build, grok-4.7 is the same price with a higher ceiling.

Yes, if you need live X data. The x_search tool has no equivalent anywhere else.

Yes, if you are already on Grok 4.5. The upgrade is a model-string change for 5.5 index points on v4.3.2, and there is no reason to stay — though the same one-line change gets you to Grok 4.7 and 46.45.

Probably not, if latency is user-visible. Around 28 seconds to first token will be felt in any interactive surface — Grok 4.5 starts in 14.02s if that is your binding constraint.

Probably not, if you routinely exceed 200K tokens of context. You will hit the doubled rate long before the 500K ceiling, and competitors offer 1M windows without the cliff.

Probably not, if output quality as humans judge it is your bar rather than benchmark placement. The Arena gap is the number to weigh there.

Not yet, if you require EU data residency on the xAI API directly.

The practical decision rule most teams land on: use Grok 4.6 as the cheap, capable implementer, not as the model you reach for first. Plan with whatever sits at the top of your quality bar, hand the mechanical execution to Grok, and let the price difference compound across the volume. That is a more defensible position than any frontier claim, and it is one Grok 4.6 holds comfortably.

FAQ

When was Grok 4.6 released?

August 12, 2026 — about 35 days after Grok 4.5. It launched simultaneously on the xAI API, in Cursor and in Grok Build, with gateway availability on OpenRouter, Vercel and Cloudflare from day one. Cloud availability followed through the rest of August: Amazon Bedrock on August 19, Google's Model Garden on August 21, and Microsoft Foundry on August 26.

What's new in Grok 4.6?

xAI describes it as a post-training release: longer supplemental training on curated model-generated data, an improved optimizer and training recipe, and better self-verification on long-horizon tasks. The one concrete API addition is the xhigh reasoning effort level. Context, price, modalities and regions are all unchanged from Grok 4.5.

How is Grok 4.6 different from Grok 4.5?

Measured by Artificial Analysis under the same harness on Intelligence Index v4.3.2, Grok 4.6 scores 44.31 against Grok 4.5's 38.81, and generates 72.9 tokens/second against 59.6. The trade-off is latency: time to first token roughly doubled, from 14.02s to 27.80s, and cost per Index task rose from $1.04 to $1.86. Same 500K context on both.

How much does Grok 4.6 cost?

$2 per million input tokens, $0.50 cached input, $6 per million output — unchanged from Grok 4.5. Prompts of 200K tokens or more are billed at $4/$1/$12 across the entire request, not just the excess. Full breakdown, including cache economics and per-task comparisons, is in our Grok 4.6 pricing and API costs guide.

What is Grok 4.6's context window?

500,000 tokens — unchanged from Grok 4.5, and the smallest among current frontier models, most of which offer 1M or more. Practically it is smaller still, because prompts at or above 200K tokens are billed at double the standard rate across the whole request.

Is Grok 4.6 better than Claude Opus 5?

Not on overall capability. On Artificial Analysis's Intelligence Index v4.3.2, Claude Opus 5 (max) scores 50.78 against Grok 4.6's 44.31 — a 6.5-point gap, far wider than the two points the pre-rebase figures suggested. Neither model leads the index now: Claude Opus 5.5 (max) sits at #1 of 224 with 57.62. Anthropic's models also dominate the top of Arena's human-preference leaderboard. Grok 4.6's advantage is price: $2/$6 against Opus 5's $5/$25, and $1.86 per Index task against $5.86.

Is there a "Grok 4.6 High" model?

No. "High" is the default reasoning_effort setting on the single grok-4.6 model id, not a separate SKU. The four supported levels are low, medium, high and xhigh. Benchmark sites list them as separate rows, which is what causes the confusion.

Should I use xhigh reasoning effort?

Usually not by default. xhigh is new in Grok 4.6 — Grok 4.5 silently downgraded it to high — and it delivers maximum reasoning depth at correspondingly higher latency. But on Artificial Analysis's Intelligence Index v4.3.2 it scores 44.20 against high's 44.31 — a tie within noise, for about 25% more per task and 11 extra seconds to first token. There is no measured accuracy reason to make it your default; reserve it for genuinely hard problems where you can measure the difference yourself.

Is Grok 4.6 available in the EU?

Not on the xAI API directly — only us-east-1 and us-west-2 regions are offered. If EU data residency is a requirement, check the Amazon Bedrock, Google Model Garden and Microsoft Foundry routes, which have their own regional footprints, before ruling the model out.