What is an AI token in LLM pricing?

A token is the basic unit of text processed by large language models. As a general rule of thumb, 1,000 tokens represent approximately 750 words in English. Models charge separately for input prompt tokens and generated output completion tokens.

How does OpenAI Batch API reduce costs by 50%?

The OpenAI Batch API processes non-urgent workloads asynchronously within a 24-hour window at an automatic 50% discount across supported models including GPT-4o, GPT-4o mini, and text embeddings.

What is the price difference between OpenAI o1 and GPT-4o?

OpenAI o1 costs $15.00 per 1 million input tokens and $60.00 per 1 million output tokens, reflecting its advanced reasoning capabilities. In contrast, GPT-4o costs $2.50 per 1 million input tokens and $10.00 per 1 million output tokens.

Back to BunusRadar Home

Free Developer Tool

AI Token & Model Cost Calculator

Estimate, compare, and forecast monthly LLM API expenditures across OpenAI o1, GPT-4o, Claude 3.5 Sonnet, Gemini, and DeepSeek with real-time prompt caching and batch discount modeling.

1. Select AI Model

Quick Presets

Prompt / Input Tokens per Request2,000 tokens

10010,00025,00050,000

Generated / Completion Tokens per Request600 tokens

502,0005,00010,000

Monthly API Requests25,000 calls

50050,000200,000500,000

Batch API (50% Off)

Asynchronous 24h turnaround

Prompt Caching (50% In)

Repeated system prefix discount

Monthly ProjectionGPT-4o

$275.00

Estimated monthly total for 25,000 requests

Input Tokens Cost

$125.00

Output Tokens Cost

$150.00

Cost / 1k Requests

$11.000

Monthly Token Volume

65.0M tokens

Compare Across Other Models

GPT-4o mini$16.50

DeepSeek V2.5$11.20

Gemini 1.5 Flash$8.25

Claude 3.5 Sonnet$375.00

How LLM Token Economics Work

Large Language Model APIs bill developers based on token volume rather than character count or server execution seconds. Because generation requires iterative next-token prediction, output tokens are priced between 3x to 4x higher than input prompt tokens across nearly all major model providers.

Word Ratio

1k Tokens

~750 English words or ~4KB of UTF-8 code.

Batch Discounts

50% Off

Available on non-streaming asynchronous API runs.

Prompt Caching

Up to 80% Off

Automatic savings on repeated system prompts.

Architectural Guidelines: Which Model to Pick?

High-Speed Microservices & High-Volume Bots: Use GPT-4o mini ($0.15/1M input) or DeepSeek V2.5. They provide sub-second responses at fractions of a cent per thousand calls.
Complex Reasoning & Multi-Step Code Architecture: Deploy OpenAI o1 ($15.00/1M input) or Claude 3.5 Sonnet. Their internal chain-of-thought processing prevents logical failures in heavy mathematical and architectural problem spaces.
Enterprise General Intelligence: Rely on GPT-4o ($2.50/1M input) for vision, document parsing, and high-quality structured output synthesis.

Frequently Asked Questions

How does OpenAI prompt caching reduce monthly bills?

When sending API calls that share the same long prefix (such as system instructions, codebases, or reference documentation above 1,024 tokens), OpenAI automatically caches the prefix. Cached input tokens receive an automatic 50% discount and cut inference latency significantly.

What is the difference between OpenAI Batch API and Realtime API?

The Realtime API provides low-latency bidirectional voice and multimodal streaming for customer service and live agents. In contrast, the Batch API is designed for offline evaluation, nightly summarization, and dataset enrichment, cutting standard token costs by 50% in exchange for a 24-hour SLA.