AI API Cost Calculator: Estimate Your Monthly Spending
Interactive tool to compare monthly costs across all major AI models — Claude, GPT, GLM, and DeepSeek.
Wondering how much your AI API usage will cost? This calculator gives you instant estimates across all major models. Enter your expected usage below and see which model gives you the best value.
Quick Presets
Estimated Monthly Cost by Model
How AI API Cost Is Calculated
AI API pricing is based on token consumption. The formula is simple:
Monthly Cost = (Daily Calls x Input Tokens x Days x Input Price)
+ (Daily Calls x Output Tokens x Days x Output Price)
Example (100 calls/day, 500 input, 800 output, 30 days, GPT-4o-mini):
Input: 100 x 500 x 30 = 1,500,000 tokens x $0.15/1M = $0.225
Output: 100 x 800 x 30 = 2,400,000 tokens x $0.60/1M = $1.44
Total: $0.225 + $1.44 = $1.67/monthWhat Is a Token?
A token is a piece of text processed by the AI model. In English, 1 token is approximately 4 characters or 3/4 of a word. In Chinese, 1-2 characters per token. Examples:
- "Hello world" = 2 tokens
- "The quick brown fox" = 4 tokens
- A typical user message (50-100 words) = 70-130 tokens
- A typical AI response (200-500 words) = 250-600 tokens
Real-World Cost Examples
Example 1: Personal AI Assistant
1 person, 50 queries/day, 100 input + 300 output tokens each
| Model | Monthly Cost |
|---|---|
| DeepSeek-V3 | $0.49 |
| GPT-4o-mini | $0.94 |
| GPT-4o | $15.75 |
| Claude Sonnet | $24.00 |
Example 2: Customer Support Chatbot
500 users, 10 messages/user/day, 150 input + 200 output tokens each
| Model | Monthly Cost |
|---|---|
| DeepSeek-V3 | $9.45 |
| GPT-4o-mini | $20.25 |
| GPT-4o | $337.50 |
| Claude Sonnet | $495.00 |
Example 3: Content Generation Pipeline
1,000 articles/day, 500 input + 1,500 output tokens each
| Model | Monthly Cost |
|---|---|
| DeepSeek-V3 | $19.80 |
| GPT-4o-mini | $31.50 |
| GPT-4o | $525.00 |
| Claude Sonnet | $810.00 |
Tips to Reduce Your API Costs
- Choose the right model: Use DeepSeek-V3 for routine tasks, Claude Sonnet for complex ones. Compare models →
- Implement model routing: Route simple queries to cheap models and complex ones to premium models. This can reduce costs by 80-90%.
- Trim your prompts: Every input token costs money. Remove unnecessary context and instructions.
- Set max_tokens: Don't let the model generate more than you need. Cap output length.
- Cache responses: Avoid calling the API for identical queries. Use a caching layer.
- Avoid peak hours: For GLM models, schedule batch jobs outside 14:00-18:00 Beijing time.
- Monitor usage: Check your dashboard regularly to catch unexpected spending.
- Use streaming wisely: Streaming improves UX without adding cost.
Frequently Asked Questions
How much does an AI API cost per month?
It depends on usage. A small project with 100 daily calls costs $3-15/month with budget models (DeepSeek-V3, GPT-4o-mini). The same usage with premium models (GPT-4o, Claude Sonnet) costs $50-200/month. Use the calculator above for precise estimates.
How is AI API cost calculated?
Cost = (input tokens x input price) + (output tokens x output price). Prices are per million tokens. For example, 100 daily calls with 500 input and 800 output tokens using GPT-4o-mini costs $1.67/month.
What is a token in AI API billing?
A token is a piece of text. In English, 1 token is about 4 characters or 3/4 of a word. In Chinese, 1-2 characters per token. "Hello world" is 2 tokens. A typical user message is 70-130 tokens.
Which AI API is the cheapest?
DeepSeek-V3 at $0.14/1M input and $0.28/1M output is the cheapest high-quality AI API. GLM-4-Flash is free for basic usage. See our cheapest AI API guide for details.
How can I reduce my AI API costs?
Use model routing (cheap for simple, premium for complex), cache repeated queries, compress prompts, set max_tokens, and batch-process during off-peak hours. These strategies can reduce costs by 70-90%.
Is there a free AI API?
GLM-4-Flash offers free basic usage. Token1.US has no minimum deposit — start with $1 and pay only for what you use. Most models cost less than $0.01 per request.