LLM API Cost Comparison 2026 — GPT-4o vs Claude vs Gemini vs Llama

Updated October 2026 · 5 min read

LLM API pricing is one of the most confusing parts of building AI products. Every provider uses different units, different context windows, and different pricing tiers — and prices change without notice. This guide explains exactly how LLM pricing works and compares the major models side by side.

How LLM API Pricing Works

Every LLM API charges per token. A token is roughly 0.75 words in English — 1,000 tokens is about 750 words or one page of text. Pricing has two components:

• Input tokens (prompt): everything you send — system prompt, conversation history, user message
• Output tokens (completion): what the model generates back — typically 2–4x more expensive per token than input

Your total cost per request = (input_tokens × input_price) + (output_tokens × output_price)

Major LLM API Prices (October 2026)

Note: Prices change frequently. Use the live calculator above for current rates.

The Real Cost of Running 1,000 API Calls Per Day

Assume a typical chatbot: 500 input tokens (system prompt + message) and 300 output tokens per request, at 1,000 requests/day:

GPT-4o vs Claude 3.5 Sonnet: Which Is Worth the Price?

GPT-4o and Claude 3.5 Sonnet are both flagship models in the same price tier. GPT-4o is slightly cheaper on input tokens; Claude 3.5 Sonnet has the edge on coding tasks and instruction following. For most production applications the quality difference is marginal — the real differentiator is which API ecosystem your team is already invested in.

The Case for Smaller Models

For classification, extraction, summarization, and Q&A on structured data, models like Gemini Flash or GPT-4o mini deliver 85–95% of flagship quality at 5–20% of the cost. Always benchmark your specific task before defaulting to the most expensive model.

What Is OpenRouter and Why Use It?

OpenRouter gives you one API key to access 200+ models from all major providers. You pay OpenRouter, who routes to whichever provider you specify. Benefits: single billing, fallback routing if one provider is down, and access to models not directly available in your region. Pricing is at or slightly above direct provider rates.