A Claude tokenizer estimates how text may be divided into tokens for Claude models. This browser tool uses a compatible local encoding rather than Anthropic's billing tokenizer, so its count is an estimate for prompt and context planning. Anthropic API token-counting and usage records remain the final source for request limits and billing.
Uses a compatible local text encoding for planning, not Anthropic's billing tokenizer. Tool use and message structure can change usage. Use this Claude tokenizer to estimate text length and cost while keeping the provider-specific accuracy boundary visible.
Provider API usage records remain the final source of truth for billing.
Input $2, cached input $0.2, and output $10 per 1M tokens.
Checked Anthropic official API pricing Claude Sonnet 5 model documentation
This Claude tokenizer uses these rates for the selected text scenario. Introductory direct Claude API rates through August 31, 2026. Anthropic lists $3 input, $0.30 cache-hit input, and $15 output per MTok starting September 1, 2026.
No. The Claude tokenizer uses a compatible local encoding to create a useful text-length estimate. It does not claim to run Anthropic's billing tokenizer, which is why the badge says Estimate rather than Exact. The final request can include message, tool, cache, and output accounting that is visible only to the provider.
Use Anthropic token-counting and usage records when a hard context limit or invoice must be exact.
A large context window can hold substantial material, but filling it is not automatically efficient. Use the Claude tokenizer on the actual system prompt, retrieved documents, conversation history, and next question. Reserve room for generated output and tool results.
When repeated context is cacheable, the cost model can apply a cache-read rate. That count is only a scenario. Cache writes, duration, eligibility, and hit behavior must follow Anthropic's current documentation.
The cost depends on normal input, eligible cache-read input, generated output, and the selected Claude model. The Claude tokenizer reads prices from one dated configuration sourced to Anthropic's pricing page; it does not treat missing data as zero or combine standard rates with batch or regional terms.
Test a typical response and a high-output response in the calculator before comparing providers.
Anthropic's API token-counting response and usage records are the source of truth for a complete Claude request. The Claude tokenizer uses a compatible local estimate and cannot reproduce provider framing, tool definitions, attachments, cache accounting, or generated output. Use the local count to edit and budget, then reconcile production limits and invoices with the provider record.
Move from token shape to total workload cost, or compare another provider's accuracy boundary.
This Claude tokenizer page measures the complete visible text with one repeatable local encoding, then labels the result Estimate because it does not run Anthropic's tokenizer. Anthropic Claude documentation defines the provider boundary. The limitation is billing scope: for a production request, compare this planning result with Anthropic's token-counting endpoint and returned usage rather than treating the browser count as billed usage. Anthropic official model documentation. Last verified: .
| Evidence | Observed result or boundary |
|---|---|
| Measured locally | Visible text and the disclosed chat-format allowance; no prompt content is sent to Anthropic. |
| Not measured locally | Provider framing, tools, attachments, cache eligibility, generated output, and final billed tokens. |
Claude Tokenizer questions
No. The Claude tokenizer is intentionally labeled Estimate. Anthropic's API usage record is the source of truth.
The cost scenario can apply a published cache-read rate, but it does not determine whether your request qualifies for or hits the cache.
Chat mode can estimate each visible message and format overhead. Tools, attachments, and provider framing still need an API-side check.
The Claude tokenizer reads the selected representative model's standard text-token prices from the centralized model file and links to the checked Anthropic source.
This Claude tokenizer is suitable for local text and budget planning, but it is not for provider invoicing. Use the Claude tokenizer for prompt and budget planning. The Claude tokenizer remains an estimate, so treat Anthropic usage records as the final token and billing evidence. Provider API usage records remain the final source of truth for billing.