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Ahmet Balaman

Is Gemini 4 Hydrogen Free? Who Can Use It and How

Ahmet Balaman

12 min read

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Is Gemini 4 Hydrogen Free? Who Can Use It and How

Yes, Gemini 4 Hydrogen can be used for free in three places: in the Gemini app (through automatic model selection), in AI Mode in Google Search, and on the free tier of the Gemini API. On the remaining surfaces it is paid. Google Sheets and Chrome require a Google AI Pro or Ultra subscription; on the paid tier of the API you pay $1.50 per million input tokens and $7.50 for output. For Antigravity, two of Google's own pages disagree.

This post is a news roundup and compilation; I have not tested the model myself. The information comes from Google's announcements, pricing page and docs. I checked the pricing page and the docs tables on November 14, 2026; those pages can change, so look at your own account before deciding. Sources are at the end. For the model itself see What is Gemini 4 Hydrogen, for rivals the Hydrogen, Sonnet 5.5 and GPT-6.1 Terra comparison, and for the Antigravity side What is Antigravity Orchestrator.

Where is it open, and to whom?

Surface Who Note
Gemini API and Google AI Studio Everyone; free tier and paid tier Release notes and pricing page
Gemini app In the model menu; free users through automatic model selection No usage limits published
Google Search (AI Mode) All users, globally, in all languages AI Mode supports Google Search blog post
Google Antigravity The sources disagree The announcement and the Antigravity blog say "paid Pro and Ultra"; two Antigravity docs pages (the plans page and the model table) list all plans, including Free and Plus. I rechecked on November 14; no page explains the difference
Gemini in Google Sheets Google AI Pro and Ultra, plus eligible business subscriptions Announcement
Gemini in Chrome Google AI Pro and Ultra Stated only in Google's post on X, not in the blog post
Android Studio Named in the developer post
Gemini for business (enterprise) Eligible subscriptions Through the API, the model menu, Antigravity and Sheets

Three notes:

  • For Antigravity, check your own account. The announcement and the Antigravity blog describe Hydrogen as open to "paid Google AI Pro and Ultra subscribers." The model table in the Antigravity docs, however, lists Hydrogen on all plans, including Free and Google AI Plus. The model menu in your own account is the most reliable way to see which one applies.
  • I make no claim about Vertex AI or the Gemini CLI. Neither surface is named on any of the Hydrogen pages I read, so I am not saying "yes" or "no."
  • It became the default in managed agents. According to the API release notes, the Antigravity agent in Gemini Managed Agents now uses Hydrogen by default.

What does a free user get in the Gemini app?

According to a footnote in the announcement, free users get Hydrogen "via auto model selection when it's the appropriate model for the prompt."

My reading of that wording is this: a free user may not be able to pick Hydrogen from the menu and force it on every request; the app decides which request goes to Hydrogen. SiliconANGLE sums up the situation as the model being open to everyone, including the free version. The two do not contradict each other, but do not read it as "free and unlimited": Google has not published a usage limit for free use.

Google also does not say that the app's default model was swapped. I come back to that below, under the 3.8 Flash heading.

The API: free tier and paid tier

The Hydrogen rows on the Gemini API pricing page (per million tokens):

Tier Input Output (incl. thinking) Cached input
Standard $1.50 $7.50 $0.075
Batch / Flex $0.75 $3.75 $0.0375
Priority $2.70 $13.50 $0.135
Free tier Free Free Free

Four facts that complete the table:

  • The price is flat across the whole 1M-token window; there is no surcharge for long context.
  • There is no promo period for Hydrogen; these prices apply from day one.
  • Every processed token is billed, and thinking tokens are billed at the output price.
  • Caching works implicitly: input served from the cache is 95% off. Explicit caching is not supported on Hydrogen.

Grounding with Google Search is charged separately: 5,000 requests per month are free (the quota is shared across Gemini 3 and later models), then $14 per 1,000 requests.

What does the free tier cost you?

The free tier asks for no money, but it has two conditions:

  • Rate limits. The free tier is rate limited. Google does not publish per-model limit numbers on the docs page; it points to the live rate-limit page inside AI Studio. You see the number there, in your own account.
  • Data use. According to the pricing page, free-tier data is used to improve Google products; paid-tier data is not.

This is my interpretation: the free tier suits learning, experimenting and prototyping; if you are going to send customer data or confidential code, moving to the paid tier is the better choice.

The other two models in the family, Argon and Carbon, are not on the free tier.

A worked cost example

Take a single request: 100,000 input tokens and 5,000 output tokens (thinking tokens included). Because prices are per million tokens, we multiply the input by 0.1 and the output by 0.005.

Scenario Calculation Amount
Hydrogen, standard 0.1 × $1.50 + 0.005 × $7.50 = $0.15 + $0.0375 $0.1875
Hydrogen, Batch / Flex 0.1 × $0.75 + 0.005 × $3.75 = $0.075 + $0.01875 $0.09375
Hydrogen, Priority 0.1 × $2.70 + 0.005 × $13.50 = $0.27 + $0.0675 $0.3375
Argon, through November 30 0.1 × $2 + 0.005 × $10 = $0.20 + $0.05 $0.25
Argon, from December 1 0.1 × $4 + 0.005 × $20 = $0.40 + $0.10 $0.50

If you send the same request 1,000 times a day, it comes to $187.50 on the standard tier and $93.75 with Batch or Flex. The same work costs $500 on Argon after December 1.

Two caveats. First, 5,000 output tokens is an assumption; because Hydrogen's default thinking level is high, your real output token count may be higher. Second, the math changes if the input comes from the cache: if all 100,000 tokens were cached, the input part would cost 0.1 × $0.075 = $0.0075 instead of $0.15.

How does the thinking level affect the bill?

Hydrogen accepts four thinking levels: low, medium, high and xhigh. If you specify nothing, high is used; minimal returns an error. Because thinking tokens are billed at the output price, the bill rises as the level rises.

Artificial Analysis's measurement shows the size of the effect (Intelligence Index v5.0.1):

Thinking level Index Cost per index task Time per task
low 27 $0.29 1.3 min
medium 41 $0.80 3.7 min
high (default) 51 $1.87 7.8 min
xhigh 54 $3.16 14.1 min

high costs more than twice as much as medium and brings 10 points. xhigh asks for $3.16 per task instead of $1.87 for three more points. These are Artificial Analysis's own index tasks; the numbers will differ on your work, but the direction is the same. Google's migration notes also suggest testing both medium and high.

Did Hydrogen replace Gemini 3.8 Flash?

Google's own wording is "recommended upgrade": the AI Studio docs describe Hydrogen as the recommended upgrade from Gemini 3.8 Flash and earlier Gemini 3 and 2.5 models. The gHacks headline and DataCamp say "replaces."

The pages I have do not support "replaced":

  • Google does not say that the default model in the Gemini app was swapped.
  • The API release notes have no deprecation or shutdown entry for gemini-3.8-flash. In fact, 3.8 Flash is the routing target for gemini-2.5-pro requests from December 1, 2026.
  • The Antigravity docs still list 3.8 Flash on all plans.

On price, the schedule is clear: 3.8 Flash is $0.75 / $3.75 through December 31, 2026, and $1.50 / $7.50 from January 1, 2027. So today it costs half of what Hydrogen costs, and the same from January. If you are going to switch on the API, see the migration guide.

Which Gemini 4 model does your plan get?

Plan Hydrogen Argon Carbon Orchestrator (Antigravity)
Free / Google AI Plus Yes: through automatic selection in the Gemini app (free users), AI Mode in Search, API free tier No No No
Google AI Pro Yes Yes: Gemini app; in Antigravity with paid Pro or a trial with eligible premium devices No Orchestrator (Argon)
Google AI Ultra Yes Yes Yes: Gemini app, Antigravity and AI Mode (rolling out to subscribers) Orchestrator (Carbon) and Orchestrator (Argon)

When reading the table:

  • "Gemini 4 for everyone" is only Hydrogen. Argon is not open to free users or Google AI Plus, and on the API it is on the paid tier only. Carbon has been generally available since November 10, but on the consumer side it is rolling out only to Ultra subscribers.
  • The API price of Argon and Carbon doubles on December 1: $2 / $10 through November 30, then $4 / $20.
  • Orchestrator comes in two variants. Orchestrator (Carbon) plans with Carbon, implements with Hydrogen and is on Ultra only. Orchestrator (Argon) plans with Argon and is on Ultra and Pro. Free and Plus plans get neither.
  • Antigravity quotas come without numbers. The plans page speaks of the highest quota, refreshed every five hours, for Ultra; a high quota refreshed every five hours until the weekly limit is reached for Pro; and a quota refreshed weekly for everyone else. No numbers are published.
  • There is no separate statement for Plus. The sources I used for this post do not describe Google AI Plus in the Gemini app separately; check your own model menu.

Watch out for fake download pages

Gemini 4 Hydrogen is not a program you download. Its weights have not been released; the model runs on Google's servers and is reached through the Gemini app, Google Search, AI Studio or the API. An installer offered as a "Gemini 4 Hydrogen download," or a page that asks for your account details in exchange for free access, is not an official Google route.

Frequently Asked Questions

Is Gemini 4 Hydrogen free?

In three places, yes: in the Gemini app through automatic model selection, in AI Mode in Google Search, and on the rate-limited free tier of the Gemini API. Sheets and Chrome require Google AI Pro or Ultra.

Can I pick Hydrogen myself in the free Gemini app?

Google's wording is that free users get Hydrogen through automatic model selection, when it is appropriate for the prompt. So there is no guarantee that you can force Hydrogen on every request, and no usage limit has been published.

How much does the Gemini 4 Hydrogen API cost?

On the standard tier, $1.50 per million input tokens, $7.50 for output and $0.075 for cached input. Batch and Flex cost half, and Priority is $2.70 / $13.50.

What happens to my data on the free API tier?

According to the pricing page, free-tier data is used to improve Google products; paid-tier data is not.

Which Gemini 4 models can I use with Google AI Pro?

Hydrogen and Argon. In Antigravity, Orchestrator (Argon) is also open. Carbon and Orchestrator (Carbon) require Ultra.

Can Gemini 4 Hydrogen be downloaded to a computer?

No. The weights have not been released; the model runs only on Google's servers.

Sources

Related Posts

Migrating from Gemini 3.8 Flash to Gemini 4 Hydrogen

Moving from Gemini 3.8 Flash to Hydrogen takes more than a new model name: minimal, explicit caching, sampling parameters and the output cap changed too.

I Tested Gemini 4 Hydrogen: 4 Thinking Levels, 1 Task

I gave Gemini 4 Hydrogen the same coding task at four thinking levels. All four solved it; time went from 14 to 198 seconds and tokens grew 14-fold.

What Is Gemini 4 Hydrogen? Specs, Price, Benchmarks

Google opened Gemini 4 Hydrogen to everyone on Nov 12, 2026: a 1M-token window, $1.50 input pricing and a free API tier. Specs and measurements in one place.

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