LLM API Cost Calculator
Calculate the cost of using large language model APIs (GPT-4, Claude, Gemini) based on token usage.
At 100 requests/day, your estimated LLM API cost is $31/month.
Why This Calculation Matters
The LLM API Cost Calculator makes AI spend predictable. Usage-based pricing can scale fast, model the math upfront so you're budgeting with reality, not surprise bills.
How to Use This Calculator
- Enter your values in the input fields, each one has a label and help text explaining what to type.
- Results appear instantly as you type; there's no "calculate" button to press.
- Change any input to compare scenarios side by side.
All math happens in your browser. Nothing you type is sent to a server, saved, or shared.
Cost Optimization Tips
- Use cheaper models for simple or bulk tasks, and premium models only when quality matters.
- Implement prompt caching where supported to cut repeat-prefix costs.
- Batch requests when your use case allows.
- Shorten prompts, tokens you don't send are tokens you don't pay for.
LLM API Pricing
LLM APIs charge per token. A token is roughly 4 characters or 0.75 words. Input and output tokens are priced separately, with output typically costing more.
Current Pricing (as of 2026)
- GPT-4o: $2.50/1M input, $10/1M output
- Claude Sonnet 4: $3/1M input, $15/1M output
- Claude Haiku: $0.80/1M input, $4/1M output
- Gemini 1.5 Pro: $1.25/1M input, $5/1M output
Cost Optimization
- Use smaller models for simpler tasks
- Implement prompt caching for repeated prefixes
- Batch requests when possible
- Optimize prompts to reduce token count
Formula
Cost per request = (input tokens / 1M × input price) + (output tokens / 1M × output price). Monthly cost = cost per request × requests per day × 30.
When to Use This Calculator
- Budget LLM spend before shipping a feature or deploying at scale.
- Compare providers on a cost-per-request basis instead of sticker price.
- Estimate inference cost for capacity planning and pricing.
Limitations & Common Mistakes
- Provider pricing changes frequently, check the provider's official pricing page for current rates.
- Token counts are estimated from text length; exact counts require the provider's tokenizer.
- Usage-based costs compound with retries, context caching, and multi-turn conversations.
Frequently Asked Questions
How much does it cost to use GPT or Claude?
Costs depend on usage. A typical chatbot conversation (~500 input + 300 output tokens) costs about $0.001-0.006 per message depending on the model. At 1,000 messages/day, that's $1-6/day. Use cheaper models for simple tasks and premium models only when needed.
What is a token?
A token is the basic unit LLMs process. In English, one token is roughly 4 characters or 0.75 words. "Hello, world!" is about 4 tokens. Longer words may be split into multiple tokens. Most APIs have a tokenizer tool to count exactly.
Where do the pricing numbers come from?
Prices default to publicly posted rates from major providers. Rates change frequently, always check the provider's official pricing page for current figures.
How do I count tokens accurately?
For exact counts, use the provider's official tokenizer. For planning, roughly 1 token ≈ 4 characters or 0.75 English words.
Is this calculator free to use?
Yes. The LLM API Cost Calculator is free, requires no signup, and runs entirely in your browser, your inputs are never sent to a server.
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