OpenRouter Cost Calculator

A lightweight utility to calculate costs for AI models (OpenRouter, OpenAI, etc.) and convert them into internal credits. Supports both Offline Calculation (using stored pricing) and Online Calculation (fetching real-time pricing from OpenRouter API).

Features

Dual Mode:
- Offline: Zero-latency calculation using your own pricing data (e.g., from DB).
- Online: Auto-fetch model pricing from OpenRouter API.
Flexible Billing: Configure margin multipliers and USD-to-Credit conversion rates.
Input-Focused: Calculates cost based primarily on input (prompt) tokens, as per modern pricing strategies.

Installation

npm install openrouter-cost-calculator

Usage

1. Offline Mode (Recommended for Speed)

Best for production environments where you store model pricing in your database. No API calls required.

import { OpenRouterCalculator } from "openrouter-cost-calculator";

// 1. Initialize
const calculator = new OpenRouterCalculator();

// 2. Configure Billing (Optional)
calculator.setBillingConfig({
  marginMultiplier: 2.0, // e.g. 2x margin
  usdPerCredit: 0.005,   // $0.005 = 1 Credit
});

// 3. Set Pricing (e.g. from your DB)
calculator.setPricing({
  prompt: "0.0000025",
  completion: "0.00001", // (Optional, ignored in calculation if not using output tokens)
  image: "0.004",
  request: "0"
});

// 4. Calculate
const result = calculator.calculateEstimate({
  prompt_tokens: 150
});

console.log(`USD Cost: $${result.usdCost}`);
console.log(`Credits: ${result.credit}`);

2. Online Mode (Auto-Fetch Pricing)

Useful for scripts or environments where you want to fetch the latest pricing from OpenRouter.

import { OpenRouterCalculator } from "openrouter-cost-calculator";

// 1. Initialize with API Key
const calculator = new OpenRouterCalculator("YOUR_OPENROUTER_API_KEY");

calculator.setBillingConfig({
  marginMultiplier: 1.2
});

// 2. Calculate directly (Fetches models internally)
// calculateCost(modelId, usage, imageCount?)
const result = await calculator.calculateCost(
  "openai/gpt-4",
  { prompt_tokens: 500 },
  0 // image count
);

if (result.modelDetails) {
  console.log(`Model: ${result.modelDetails.id}`);
  console.log(`Input Cost: $${result.usdCost}`);
} else {
  console.log("Model pricing not found");
}

Configuration

Option	Description	Default
`marginMultiplier`	Multiplier for revenue calculation (e.g. 2.0 = 200% price)	`1.0`
`usdPerCredit`	USD value of 1 internal credit unit	`undefined`
`minimumCredit`	Minimum credits to charge if calculated < min	`0`

License

MIT