ChatGPT Cost Calculator
Estimate what your ChatGPT / GPT-4o usage costs per month: paste a text sample, count tokens, compare input vs output pricing across models. Free, no signup.
Wondering what it would cost to run your workload through the ChatGPT API instead of the $20 subscription? Paste a representative sample of your prompts and responses: the calculator counts tokens exactly the way the API does, then multiplies by current GPT-4o, GPT-4o mini, and o1 pricing.
Because token pricing differs between input and output, and because system prompts quietly inflate every request, the calculator breaks costs down per component — so you can see whether a cheaper model, a shorter system prompt, or batch pricing would cut your bill.
100% in-browser · no upload · no signup · nothing you paste or drop here leaves your device
LLM Token & Cost Calculator
Estimate token counts and API costs for OpenAI, Anthropic, Google, Meta & DeepSeek models.
LLM API prices are per 1M tokens as of June 2026 and may change without notice. Token estimates use model-specific chars-per-token ratios and may vary ±10-20% from actual counts.
How tokenizers chop text and price API calls — illustrated
LLMs don't read characters — they read tokens. A tokenizer (BPE or SentencePiece, e.g. GPT's cl100k_base/o200k_base, Claude's tokenizer, Gemini's SentencePiece) splits text into subword units, and English averages roughly 4 characters per token (CJK and dense code can differ). This tool estimates input tokens as ceil(chars ÷ charsPerToken) for each model, then computes cost as tokens ÷ 1,000,000 × per-1M price for input and output and sums them. It also shows what fraction of the model's context window the call would consume.
A token is often a whole common word, or a subword chunk of a longer word. Because each model ships its own tokenizer and its own per-1M prices, the same prompt yields slightly different token counts and costs across providers.
Ken, an app developer, is about to call an LLM endpoint with a 1,024-character prompt and wants to know which model is cheapest before the invoice lands.
- Paste the prompt:1,024 chars ÷ ~4 chars/token ≈ 256 input tokens (English text)
- Set output budget:500 output tokens via the slider — the completion allowance
- Compare models:Rows sort by total cost; input and output priced separately per model
- Watch context %:(input + output) ÷ context window × 100 — flagged red past 80%
About this ChatGPT cost calculator
This page covers gpt-4o pricing calculator, chatgpt api price estimator, how much does chatgpt api cost, openai token cost — all the same underlying task as ChatGPT cost calculator. The tool above is FreeToolHub's token calculator embedded in full: every feature works right here, and nothing you process is uploaded to any server.
Related pages
- OpenAI API Pricing Calculator — OpenAI API pricing calculator
- LLM Cost Comparison — 12+ Models Side by Side — LLM cost comparison
Frequently asked questions
How accurate is the ChatGPT cost estimate?
Token counting uses the same tokenizer family as the ChatGPT models, so counts match API responses within a few percent. Prices are the published per-million-token rates; always confirm current pricing on OpenAI's pricing page, as rates change with model updates.
Does the calculator store my text?
No. Tokenization happens entirely in your browser — the text you paste is never sent anywhere. That makes it safe to estimate costs with real customer prompts, internal documents, or unreleased product copy.