Claude Token Counter Online — Free, No Anthropic Account

Anthropic offers a count_tokens API endpoint, but using it requires an API key and a code call. For one-off counts — like checking whether your prompt fits or estimating cost before sending — a free browser-based counter is faster.

How to Count Claude Tokens in 5 Seconds

1. Open the Token Counter
2. Paste your prompt or document
3. See token count, word count, character count, and estimated Claude cost
4. Adjust the text and watch the count update live

No API key, no signup, no install. The counter runs entirely in your browser — your prompt never leaves your device, which matters for confidential or proprietary content.

Claude Pricing by Token

Model	Input ($/M)	Output ($/M)	Context window
Claude Haiku 3.5	$0.80	$4.00	200,000 tokens
Claude Sonnet 4	$3.00	$15.00	200,000 tokens
Claude Opus 4	$15.00	$75.00	200,000 tokens

All Claude models share the same 200K context window. The pricing tier determines quality and cost, not capacity.

Real Examples — Tokens for Common Claude Prompts

Prompt type	Approximate tokens	Cost on Sonnet 4
Short question (10 words)	13 input	$0.00004 input
Detailed prompt (100 words)	130 input	$0.0004 input
Long instruction (500 words)	650 input	$0.002 input
1-page document (250 words)	325 input	$0.001 input
5-page document (1,250 words)	1,625 input	$0.005 input
20-page document (5,000 words)	6,500 input	$0.020 input
Full novel (50,000 words)	65,000 input	$0.195 input

Claude handles a full novel as input for under 20 cents on Sonnet 4. The output cost depends on what you ask Claude to generate from it.

Approximation vs Exact Count

Browser counters give a word-based approximation. Anthropic's count_tokens API gives the exact count using Claude's actual tokenizer. For English prose, the two agree within 5%. For code and special characters, the variance is larger (5-15%).

For estimation and context window checks, the approximation is fine. For exact billing math, use the official API count.

When to Use Each Approach

Use the browser counter when you:

• Need a quick check before sending a prompt
• Want to estimate cost for a project
• Are sizing a document to fit Claude's context window
• Don't want to write code or get an API key
• Need to share token math with a non-developer

Use the Anthropic count_tokens API when you:

• Are building production code that needs exact counts
• Need to truncate input to fit a precise token budget
• Are tracking exact billing per customer
• Need 100% accuracy on edge cases (rare characters, special tokens)

Privacy: Why Browser Counting Wins for Sensitive Prompts

Anthropic's count_tokens API requires sending your text to Anthropic's servers. For most use cases, that's fine. For confidential text — legal contracts, internal HR documents, source code, customer data — you may not want to send it anywhere.

Browser-based token counters run locally. Your text is processed in your browser's JavaScript engine. Nothing is uploaded, logged, or stored. The result is the same approximate count without the privacy trade-off.