TL;DR (October 20, 2026): Google Antigravity is free to start, with a quota that refreshes weekly and Gemini 3.8 Flash as the core model. Google AI Pro ($19.99 a month) refreshes the quota every five hours until a weekly limit and, since October 13, includes Gemini 4 Argon, but only on a paid Pro subscription, not a trial. Google AI Ultra ($99.99 or $199.99, sold as 5x and 20x Pro usage) gets the highest five-hour quota and weekly limits. Past the quota, Pro and Ultra can spend AI credits. The other route is a Gemini API key in the Antigravity CLI: Gemini 4 Argon costs $2 input and $10 output per million tokens until November 30, then doubles to $4 and $20 on December 1.
Antigravity has two price lists that look unrelated. One is a consumer subscription ladder sold through Google One, where you never see a token price and the limit is an opaque quota. The other is the Gemini API, where every token has a price and nothing stops you except your billing account. This page sets out both as of October 2026, how the quota refreshes, what the AI credit overage does, and when paying for tokens beats paying for a plan.
Antigravity plans and prices
| Plan | US price | Antigravity quota | Reasoning models in Antigravity |
|---|---|---|---|
| Individual (no Google AI plan) | $0 | A "meaningful quota, refreshed weekly", plus a weekly rate limit | Gemini 3.8 Flash; Claude Sonnet 4.6 and Opus 4.6; GPT-OSS-120b |
| Google AI Plus | $4.99 / month | Same as Free (a quota refreshed weekly); Google lists no Antigravity benefit for Plus, and Plus cannot buy AI credits | Same as Free |
| Google AI Pro | $19.99 / month | A "high, generous quota, refreshed every five hours until the weekly limit is reached", and a higher weekly limit | Gemini 4 Argon and Claude Opus 5.5 and Sonnet 5.5 (paid Pro only, not trials); Gemini 3.8 Flash; the Claude 4.6 pair; GPT-OSS-120b |
| Google AI Ultra 5x | $99.99 / month | The highest quota, refreshed every five hours, and the highest weekly limits; Google lists "higher" Antigravity rate limits for 5x | Gemini 4 Argon, Gemini 3.8 Flash, Claude Opus 5.5 and Sonnet 5.5, GPT-OSS-120b |
| Google AI Ultra 20x | $199.99 / month | As Ultra, with the "highest" Antigravity rate limits | As Ultra 5x |
| Gemini Enterprise | Standard and Plus from $30 per seat a month; pay-as-you-go with a $0 seat fee | Business terms under Google Cloud, spend caps across API and subscription | Adds Gemini 3.7 Flash, 3.6 Flash and Gemini 3.1 Pro |
From Antigravity's pricing, Plans and Models pages and Google's Gemini subscriptions page (United States), read October 20, 2026. Prices before tax. Claude Sonnet 4.6, Claude Opus 4.6 and GPT-OSS-120b are marked for removal on November 2, 2026.
Every plan gets unlimited Tab completions and access to all product features, including scheduled tasks and the CLI. What changes as you pay more is the reasoning quota, how often it refreshes, and which models you can pick. One easy miss: Gemini 4 Argon is not available in the Antigravity IDE. Google lists it for the Antigravity App, the Antigravity CLI and the IDE extensions only.
How the quota refreshes
Antigravity does not count prompts. Google's Plans page says the rate limits "correlate with the amount of work done by the agent", so a quick, simple task costs little and a long multi-step task costs a lot. The refresh rule depends on the plan:
- Free and Plus: the quota refreshes once a week. When it is gone, you wait for next week.
- Pro: the quota refreshes every five hours, but only until you reach the weekly limit. A heavy Monday and Tuesday can therefore end your week even though the five-hour window keeps resetting.
- Ultra: the same five-hour refresh with the highest weekly limit.
Quotas are tracked per model. In the CLI, /usage (alias /quota) opens a Model Quotas panel with what is left for each model; in the app, the model selector's usage view shows the weekly and five-hour limits remaining, and the Settings page shows quota usage across models. Since October 10, the CLI reports a spent individual quota immediately instead of retrying the request.
Google also says the baseline limits are "primarily determined by available capacity" and "subject to modification", so a quota that felt larger last month may simply have been changed. Budget on the refresh rules above, not on a remembered number.
The catch: Gemini 4 Argon burns quota fast
Gemini 4 Argon arrived in Antigravity on October 13 for Google AI Pro and Ultra subscribers. The next day, an r/GoogleGeminiAI post argued that $20 Pro users were locked out of Argon while Claude and Codex give flagship models for the same price. Antigravity's Models page now lists Argon for Pro, with a footnote: paid Pro subscriptions only, not trials. If you got Pro through a free trial or promotion, Google's FAQ says to submit an upgrade request to switch to paid Pro, or move to Ultra.
The second complaint is consumption. An r/GeminiAI user wrote that one benchmark task on Argon at Medium used 66% of their weekly Argon quota. That is a single report, and some commenters questioned the method, but they match how Google describes the quota: it follows the work done, and a frontier model doing a long agent run does a lot of work. The practical rule is to plan or review with Argon and leave routine edits to Gemini 3.8 Flash, which every plan includes.
AI credits: what happens past the quota
Google AI Pro and Ultra members can buy AI credits through Google One and spend them when a model's baseline quota runs out. Google's Plans page says credits are consumed at standard Gemini Enterprise consumption pricing. The details that matter:
- Who can buy: Pro and Ultra only. Not Google AI Plus, not Japan, and not members billed through a third party, Pixel Pass or Apple.
- Pack sizes: Google's help page gives 2,500, 5,000 and 20,000 credits as examples. It does not publish a price per credit.
- Auto-reload: available after a first purchase, limited to 5 reloads a day.
- The overage switch: the "AI Credit Overages" setting is either Never (wait for the quota to refresh) or Always (spend credits automatically, then go back to the quota when it refreshes). In the CLI the same switch is
useG1Creditsinsettings.json, and/creditsshows the balance. - Expiry: credits may expire after a period set when you buy them, and credits are shared with your Google One family group.
If you set overages to Always and use Argon heavily, you are on usage-based billing without a token price on screen. Since October 2 the CLI stops immediately with "Your AI credits balance is too low to continue" when neither quota nor credits cover a request, instead of retrying for minutes.
The API key route
Antigravity's Plans page says there is no bring-your-own-key option for extra rate limits on consumer plans. The Antigravity CLI is different: it can run directly against the Gemini API with a GEMINI_API_KEY instead of a Google sign-in, and then every token is billed at Gemini API prices. Google's FAQ also says that using an Antigravity login inside third-party tools such as Claude Code, OpenClaw or OpenCode breaks the Terms of Service and can get the account suspended, and recommends a Gemini Enterprise or Google AI Studio API key for that instead.
| Gemini API, Standard, per 1M tokens | Input | Output (incl. thinking) | Context caching |
|---|---|---|---|
| Gemini 4 Argon, through Nov 30, 2026 | $2.00 | $10.00 | $0.10 (implicit only) |
| Gemini 4 Argon, from Dec 1, 2026 | $4.00 | $20.00 | $0.20 (implicit only) |
| Gemini 3.8 Flash, through Dec 31, 2026 | $0.75 | $3.75 | $0.075 |
| Gemini 3.8 Flash, from Jan 1, 2027 | $1.50 | $7.50 | $0.15 |
From Google's Gemini API pricing page, read October 20, 2026. Gemini 4 Argon is not on the API free tier. Batch and Flex are half the Standard rate; Priority is 1.8x.
Two things stand out. Both models have a scheduled price increase, so any budget you set in October is wrong by December or January. And Argon supports implicit caching only: you cannot pin a cached prefix, so a long agent loop pays the cheap cache rate only when Google's cache happens to hit. One r/GeminiAI commenter called Argon "extremely expensive on agentic tasks due to a poor cache hit rate"; that is one user's experience, but the implicit-only rule is in Google's price table. Our Gemini 4 Argon API pricing page works through the December increase in detail.
When a plan beats a key, in numbers
Take one heavy agent session: 3 million input tokens of which 2.5 million hit the cache, plus 100,000 output tokens. At Standard API rates:
| Model and date | Cached 2.5M | Uncached 0.5M | Output 0.1M | Session | Sessions per $19.99 |
|---|---|---|---|---|---|
| Argon, October and November | $0.25 | $1.00 | $1.00 | $2.25 | About 9 |
| Argon, from December 1 | $0.50 | $2.00 | $2.00 | $4.50 | About 4 |
| Gemini 3.8 Flash, 2026 | $0.19 | $0.38 | $0.38 | $0.94 | About 21 |
If your cache hit rate is worse than the 83% assumed here, the API cost rises quickly, because uncached Argon input costs 20 times the cached rate. Read the other way: if you would run more than about four heavy Argon sessions a month after December 1, the $19.99 Pro plan is the cheaper way to get them, as long as the weekly limit lets you. If you run fewer, or need to run Antigravity from scripts and CI, an API key with a spend cap on the Gemini side gives you a predictable bill instead of a quota that changes without notice. Live rates for these and other models are in our AI price tracker.
What changed in October 2026
- October 13: Gemini 4 Argon rolled out in the Antigravity App and CLI for Google AI Pro and Ultra, and for eligible Gemini Enterprise subscriptions.
- October 2 and October 10: the CLI started stopping at once when AI credits run out, and reporting a spent individual quota without retrying.
- Announced for November 2: Claude Sonnet 4.6, Claude Opus 4.6 and GPT-OSS-120b leave Antigravity. Free and Plus users lose their only Claude models; on Pro, the Claude 5.5 models remain for paid subscribers.
- Scheduled: Gemini 4 Argon API prices double on December 1, 2026, and Gemini 3.8 Flash API prices double on January 1, 2027.
If you resell Antigravity-style agent work to your own customers, the quota model is the hard part: you cannot bill per task from a quota you cannot see. UsageBox meters the usage events your own product emits, per customer and per model, so you can price agent work on what it actually consumed.
Sources
Read on October 20, 2026: Antigravity's Plans page; Antigravity's pricing page, Models page, FAQ, CLI AI credits and /usage documentation, changelog, and the October 13 blog post on Gemini 4 Argon; Google's Gemini subscriptions page for US prices; Google One help articles on purchasing and managing AI credits; Google's Gemini API pricing page. Community reports are from public threads in r/GoogleGeminiAI and r/GeminiAI posted in October 2026.