GPT-5 Token Calculator — Count Tokens & Estimate API Cost
GPT-5 Token Calculator is a free, browser-based developer tool that counts tokens for OpenAI's GPT-5, GPT-5 mini and GPT-5.5 using the official o200k_base tokenizer — the same tokenizer OpenAI's API uses for billing. Unlike word-based counters, it returns invoice-accurate token counts and live API cost estimates entirely in your browser: no uploads, no API keys, no sign-up. It is one of 90+ models covered by TokenCalc, a free AI token calculator for developers.
→ Open the GPT-5 token counter — paste any prompt, article or code, get invoice-accurate token counts and costs in seconds.
GPT-5 tokenizer and pricing (2026)
| Model | Tokenizer | Input / 1M tokens | Output / 1M tokens | Context window |
|---|---|---|---|---|
| GPT-5 | o200k_base | $1.25 | $10.00 | 400K |
| GPT-5 mini | o200k_base | $0.25 | $2.00 | 400K |
| GPT-5.5 | o200k_base | $2.50 | $15.00 | 200K |
| GPT-4o | o200k_base | $2.50 | $10.00 | 128K |
GPT-5 token calculator by the numbers
- 90+ LLM tokenizers supported — every OpenAI model uses exact tiktoken counts
- 400K token context window on GPT-5 and GPT-5 mini
- 1.3 average tokens per English word (o200k tokenizer)
- $1.25 / $10.00 per 1M input / output tokens for GPT-5
- 100% in-browser — your text never leaves the device
- 0 uploads, 0 API keys, 0 cost
How many tokens is a word in GPT-5?
One English word averages ~1.3 tokens with the o200k tokenizer (roughly 4 characters per token). Token counts are never a fixed ratio, because the tokenizer uses Byte-Pair-Encoding:
- Common words like
the,andorthatare usually a single token. - Long or rare words split into several tokens —
internationalization≈ 4 tokens. - Code costs more than prose:
{,},=>tokenize densely. - Chinese text runs ~0.6–1.2 tokens per character — a "words" estimate can be off by 30%.
Why count GPT-5 tokens accurately?
OpenAI bills by tokens, and GPT-5's context window is 400K tokens. A prompt that looks fine in a word counter can silently eat your context budget or inflate your invoice. Counting with the real tokenizer removes the guesswork:
- Budget context — know how many tokens a document takes before it enters your prompt.
- Forecast costs — see the exact $ cost of a request at GPT-5's per-1M-token rates.
- Compare models — the same text tokenizes differently across GPT-5, Claude and Gemini.
GPT-5 token counter — free and private
Our AI Token Calculator runs the actual tiktoken tokenizer right in your browser — no upload, no API key, no sign-up. Paste your prompt, article or dataset and get invoice-accurate token counts for GPT-5, GPT-4o, o1, o3 and every other OpenAI model, plus proven estimates for Claude, Gemini, Llama, DeepSeek, Qwen and 90+ more.
→ Open the GPT-5 token counter (free, private)
GPT-5 token FAQs
How many tokens does GPT-5 have per word?
About 1.3 tokens per English word, or ~4 characters per token. Always verify with the real tokenizer — the ratio depends on vocabulary and code content.
Is the GPT-5 token count exact?
Yes for OpenAI models. The calculator uses the official o200k_base tokenizer (tiktoken), the same code path OpenAI's API uses for billing, so counts match to the token.
Does the GPT-5 token counter upload my text?
No. Tokenization runs entirely in your browser. Your text is never sent to any server.
What is a token in GPT-5?
A token is the smallest unit of text that GPT-5's o200k tokenizer processes — roughly one English word equals 1.3 tokens. GPT-5's 400K context window is measured in tokens, so knowing your token count tells you exactly how much text fits in a prompt.
Is GPT-5 Token Calculator a good alternative to tiktoken?
Yes for most use cases. tiktoken is OpenAI's Python library for counting tokens; GPT-5 Token Calculator runs the identical o200k tokenizer in the browser — no Python, no install, no API key — and additionally shows live cost estimates across every OpenAI model.