# What is an AI token, and what does one cost?

An AI token is the unit a language model reads and writes, roughly four characters or three-quarters of an English word, and the unit its price is quoted in. As of September 18, 2026, a million input tokens costs from $0.030 to $150 across the 157 priced models in our registry; output tokens cost more, and cached input tokens less. A 500-word email is about 670 tokens: $0.00013 to read on GPT-5.6 Luna, $0.0067 on GPT-6 Astra.

Prices from the BenchLM pricing registry, updated September 18, 2026. Counts on this page use OpenAI's o200k_base tokenizer, the one behind the current GPT models. Anthropic, Google and open-weight models use their own tokenizers, so the same text is a different number of tokens on each; the ratios are close for English prose and drift for code, other languages and JSON.

## How many tokens is that?

| Text | Characters | Words | Tokens (o200k_base) | Characters per token |
|---|---:|---:|---:|---:|
| A greeting | 13 | 2 | 4 | 3.25 |
| A plain English sentence | 44 | 9 | 10 | 4.4 |
| A sentence about tokens | 55 | 9 | 11 | 5 |
| One long word | 34 | 1 | 10 | 3.4 |
| A JSON fragment | 46 | 4 | 15 | 3.07 |
| A short email (about 120 words) | 580 | 109 | 120 | 4.83 |

## What a million tokens costs today

| Model | Input per 1M | Cached input per 1M | Output per 1M |
|---|---:|---:|---:|
| GPT-5.6 Luna (OpenAI) | $0.200 | $0.020 | $1.20 |
| DeepSeek V4.1 Flash (DeepSeek) | $0.300 | $0.006 | $1.20 |
| Claude Haiku 4.5 (Anthropic) | $1.00 | $0.100 | $5.00 |
| Gemini 3.5 Flash (Google) | $1.50 | $0.150 | $9.00 |
| GPT-5.6 Terra (OpenAI) | $2.00 | $0.200 | $12.00 |
| Claude Sonnet 5 (Anthropic) | $2.00 | $0.200 | $10.00 |
| Grok 4.6 (xAI) | $2.00 | $0.500 | $6.00 |
| GPT-5.6 Sol (OpenAI) | $4.00 | $0.400 | $20.00 |
| Claude Opus 5 (Anthropic) | $5.00 | $0.500 | $25.00 |
| GPT-6 Astra (OpenAI) | $10.00 | $1.00 | $50.00 |

Cheapest priced row: Qwen3.7 Flash at $0.030 / $0.130; most expensive: o1-pro at $150 / $600 (157 priced models).

## What everyday units cost

### GPT-5.6 Luna

| Unit | Tokens | As input | As output |
|---|---:|---:|---:|
| A 500-word email | 670 | $0.00013 | $0.00080 |
| A 10-page report (about 5,000 words) | 6,700 | $0.00134 | $0.00804 |
| A 300-page book (about 90,000 words) | 120,000 | $0.024 | $0.144 |
| A million tokens | 1,000,000 | $0.200 | $1.200 |

### Claude Sonnet 5

| Unit | Tokens | As input | As output |
|---|---:|---:|---:|
| A 500-word email | 670 | $0.00134 | $0.00670 |
| A 10-page report (about 5,000 words) | 6,700 | $0.013 | $0.067 |
| A 300-page book (about 90,000 words) | 120,000 | $0.240 | $1.200 |
| A million tokens | 1,000,000 | $2.000 | $10.000 |

### GPT-6 Astra

| Unit | Tokens | As input | As output |
|---|---:|---:|---:|
| A 500-word email | 670 | $0.00670 | $0.034 |
| A 10-page report (about 5,000 words) | 6,700 | $0.067 | $0.335 |
| A 300-page book (about 90,000 words) | 120,000 | $1.200 | $6.000 |
| A million tokens | 1,000,000 | $10.000 | $50.000 |

## Where prices are heading

The BenchLM Token Price Index (frontier tier) stands at 16 for 2026-09, 84% below its 2023-03 base, with a median blended price of $6.00 per million tokens across 21 constituents; up 72% year on year.

## Frequently asked questions

### What is a token in AI?

A token is the unit a language model reads and writes: a word, part of a word, a number or a punctuation mark, chosen by the model's tokenizer. In English prose one token is about four characters or three-quarters of a word. Prices are quoted per million tokens, separately for input, cached input and output.

### How many tokens is a word?

About 1.3 tokens per English word on average, so 750 words is roughly 1,000 tokens. Short common words are one token; longer or rarer words split into several. On this page "supercalifragilisticexpialidocious" is 10 tokens on OpenAI's o200k_base tokenizer, while "Hello, world!" is 4.

### How much do AI tokens cost?

As of September 18, 2026, a million input tokens costs from $0.030 to $150 across the 157 priced models in the BenchLM registry, and a million output tokens from $0.130 to $600. A single token therefore costs a fraction of a thousandth of a cent; the bill comes from volume, and from output tokens costing several times input tokens.

### Why do output tokens cost more than input tokens?

Generating a token means running the whole model once per token, one after another, while reading input is processed in parallel. Providers price that difference: on the table above output is typically five to six times the input rate. Cached input is cheaper still, usually a tenth of the input rate, because a repeated prefix is not recomputed.

### Are tokens the same across models?

No. Each provider has its own tokenizer, so the same text is a different number of tokens on GPT, Claude, Gemini or an open-weight model, and prices per million tokens are not directly comparable without that count. Our token counter shows the count per model; the pricing calculator applies each model's own rates to your token mix.

## Related

- [LLM token counter and AI token calculator](https://benchlm.ai/tools/token-counter)
- [LLM API pricing comparison and calculator](https://benchlm.ai/llm-pricing)
- [Token Price Index](https://benchlm.ai/token-price-index)
- [LLM pricing updates](https://benchlm.ai/llm-pricing-trends)

Canonical page: https://benchlm.ai/ai-token-cost