Short answer: The Gemini API starts on a free tier, and you move to the paid tier by linking a Cloud Billing account to your project and, under Google's current prepay model, adding at least 5 US dollars (or the equivalent) of credit. Indian developers get one extra route: Google Cloud lists UPI for qualified Indian organizations paying in INR.
Disclosure: this post has no affiliate links in the main steps. One section near the end mentions AICredits (affiliate link) and the Scapia card (referral link) as optional fallbacks. Everything about Google's billing below comes from Google's own docs, read on 23 Oct 2026. I did not enable billing or pay anything, so the steps are documented, not run by me.
You built something on the free tier, the rate limits started biting, and now you have to hand Google a payment method. The existing post on the Gemini Flash free tier for Indian developers covers using the free tier. This one covers what happens when you leave it.
What is the difference between the free tier and the paid tier?
From Google's billing docs and pricing page, read today:
- Free: new accounts start here, with access to certain models within rate limits. The pricing page says some models are not available on the free tier.
- Paid: higher rate limits, context caching and the Batch API (described as a 50% cost reduction), plus access to the most advanced models.
- Data use: free-tier content may be used to improve Google's products. On the paid tier it is not. If you send client data, this alone justifies paying.
How does Gemini API billing get enabled?
The docs give this path:
- Go to the AI Studio API keys or Projects page and click Set up billing in the Billing Tier column for your project.
- Choose an existing billing account or create one, and confirm your country, contact information and payment method.
- Complete the prepayment, or select Postpay if it is offered to you.
Prepay and postpay differ in ways that matter.
| Prepay | Postpay | |
|---|---|---|
| How it works | Buy credits in advance | Costs accrue; charged at month end or at your spend cap |
| Minimum / maximum | 5 dollars / 5,000 dollars | Not stated on the page I read |
| Expiry | Credits expire after 12 months, generally non-refundable | Not applicable |
| Auto-reload | Optional, with a monthly auto-charge limit | Automatic payment to the method on file |
The docs also warn that prepay credits apply only to Gemini API usage, and that Google Cloud Welcome credits cannot be used for Gemini API usage on accounts opened after 2 March 2026.
What payment methods does Google Cloud accept in India?
On the payment methods page, read today:
- Cards: American Express, Mastercard, Visa and Visa or Mastercard-logo debit cards.
- UPI: offered to qualified Indian organizations that pay in INR.
- Debit cards that require two-factor authentication are not accepted for payment, per the page.
- Recurring limit: the page warns your bank might decline automatic card charges above 15,000 rupees for recurring payments, and recommends a manual payment if automatic ones are declined.
A separate UPI page lists the requirements: an Indian billing address and bank account, billing in INR, a registered UPI account, and a prepayment of about 500 to 1,000 rupees before UPI can be used. Manual payments go through Payment overview, Make a payment, Pay with UPI, then you scan the QR code. Automatic payments need you to add UPI as a payment method and approve the mandate in your UPI app.
Notice the word "organization". I could not confirm whether an individual with an AI Studio account gets the UPI option in the prepay flow. Open the payment screen before you plan around it.
How do the usage tiers and spend caps work?
The docs list tiers you reach as you pay:
| Tier | Qualification | Monthly cap |
|---|---|---|
| Free | Active project or free trial | Not applicable |
| Tier 1 | Link an active billing account | 250 dollars |
| Tier 2 | Paid 100 dollars and 3 days since first successful payment | 2,000 dollars |
| Tier 3 | Paid 1,000 dollars and 30 days since first payment | 20,000 to 100,000+ dollars |
When the cap is hit, the docs say service is paused for all projects linked to that billing account until the next billing cycle. Project-level spend caps exist but are marked experimental, so do not rely on them as your only guard.
What are the common Gemini billing errors?
From the docs:
- HTTP 402 Payment Required: on Prepay, the balance hit zero. Every API key in the linked projects stops until you add credits. Fix: top up, or turn on auto-reload.
- "No credits": the balance is depleted.
- "Set up Prepay": the plan still needs setup.
- "The billing account type is inactive or unsupported": the account is not eligible for the paid tier. Create or choose a different billing account.
- Other Cloud debts: an unpaid balance on another Google Cloud service can suspend Gemini access even with prepay credits left.
- Failed 400 or 500 requests are not charged, but they still count toward quota.
For card declines, my OpenAI payment-failed checklist applies almost line by line: international usage, limits, OTP, recurring-payment rules.
What if you cannot get a payment method accepted?
Direct billing is the cheapest per token when it works, so exhaust that first. After that:
- A different card. The best credit card for AI APIs in India lists options. The Scapia card (referral link) advertises zero forex markup and lifetime-free status, but its terms changed in 2026, so verify in the app before applying.
- An INR gateway. AICredits takes UPI top-ups from 50 rupees and exposes an OpenAI-compatible endpoint at
https://api.aicredits.in/v1. Per its docs, prices carry a 5% forex buffer and a 5% platform fee, and a top-up has a Razorpay charge of about 2.36%. I did not check whether it carries every Gemini model; look at its model list. Walkthrough: paying for an LLM API with UPI. - Non-affiliate fallback. Have your company's finance team set up the Cloud Billing account, which also solves invoicing. See the GST invoice post.
A pre-flight checklist
- Decide whether you need paid-tier data handling or higher limits.
- Open Set up billing for your project and read the payment screen before committing.
- Prefer a credit card or UPI over a debit card that forces two-factor authentication.
- Start with the 5 dollar minimum and turn on auto-reload only with a monthly limit you chose.
- Set a budget alert in Cloud Billing, since the project spend cap is experimental.
Last checked: 23 Oct 2026. Google edits these pages often; confirm amounts and limits before you pay.
