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Gemini API Cost Estimator

The Gemini API Cost Estimator converts expected token usage into an estimated API bill using editable input and output rates. It helps developers model a production workload, compare prompt designs, or check whether a planned request volume fits a monthly spending limit.

The estimator does not hard-code a model price because Gemini offers multiple models and billing terms can change. Enter the rates that apply to the exact model and usage tier you intend to use. The output shows total spend, the input/output split, and average cost per call so that changes in prompt length or response limits are easy to evaluate.

Cost inputs

tokens
tokens
USD
USD
USD
Result
—
Estimated cost
Token charges—
Input charges—
Output charges—
Average cost per call—

1. Choose the workload period

Decide whether the call count represents a day, month, release cycle, or another consistent period.

2. Enter call and token averages

Use logs or a representative test set to estimate the average prompt and completion size.

3. Apply the correct model rates

Enter the current Gemini input and output prices for the model and billing tier you will use.

4. Add non-token charges

Include applicable tool, storage, search, or other API fees as one combined amount.

5. Inspect the cost split

Review token charges, total estimated cost, and average cost per call.

Input charge = Calls × Input tokens per call ÷ 1,000,000 × Input rate Output charge = Calls × Output tokens per call ÷ 1,000,000 × Output rate Estimated API cost = Input charge + Output charge + Other charges

Where:

  • Calls — number of API requests in the chosen period.
  • Token rates — prices per one million tokens for the selected model.
  • Other charges — optional non-token API fees for the same period.

Assumptions: All calls are modeled with the entered averages. Provider-specific cache, batch, regional, and enterprise adjustments are not applied automatically.

What the result means

The main result is the estimated Gemini API charge for the entered usage period.

Verify rates against the provider documentation or your contract before using the estimate for procurement.

Given: 50,000 Gemini API calls, 900 input tokens and 250 output tokens per call, $2.00 per million input tokens, $8.00 per million output tokens, and no other charges.

Calculation: Input = 45,000,000 ÷ 1,000,000 × $2.00 = $90.00. Output = 12,500,000 ÷ 1,000,000 × $8.00 = $100.00.

Result: Estimated API cost = $190.00, averaging $0.0038 per call.

This baseline can be rerun with shorter prompts or responses to quantify potential savings.

Which model price should I enter?

Use the rates for the exact Gemini model and service tier used by your application. Do not mix input pricing from one model with output pricing from another.

How should retries be handled?

Include retry calls in the total call count or increase the average call volume by the observed retry rate.

Can I include prompt caching discounts?

Yes, but the calculator has one input-rate field. Enter a weighted effective input rate or run cached and uncached traffic separately.

Are taxes and currency conversion included?

No. Rates are treated as USD inputs and taxes or foreign-exchange effects must be added outside the calculator or in other charges.

What is the best source for token averages?

Production usage logs are best. Before launch, use a test set that represents the actual distribution of prompt and response lengths.