Every LLM API call is billed and context-limited by tokens, not characters or words, and the exact split varies by model family. Before you paste a huge prompt into an API call, it helps to know roughly how many tokens you’re about to send — that’s what this tool estimates instantly in your browser.
What Is the LLM Token Counter?
LLM Token Counter is one of the tools in WebdevToolbox’s AI & Prompt Tools category. Paste any text and see estimated token counts for GPT-4/GPT-3.5, Claude, and Llama/Mistral-style tokenizers side by side, updated live as you type.
How to Use It
- Open the tool at /tools/token-counter.
- Paste or type your prompt, document, or code.
- Read the estimated token count per model family in the sidebar.
- Compare against the listed context windows to see how much room you have left.
Key Features
- Multi-model estimates — GPT, Claude, and Llama/Mistral side by side, since each tokenizer packs text differently.
- Live updates — no button to click; counts refresh about 150ms after you stop typing.
- Character and word counts — shown alongside token estimates for quick sanity checks.
- Context window reference — common limits for GPT-4o, GPT-3.5, Claude 3.5 Sonnet, and Llama 3.1 listed for comparison.
- 100% client-side — your text never leaves the browser.
When to Use the LLM Token Counter
- Before an API call — sanity-check that your prompt plus expected response fits the model’s context window.
- Cost planning — pair this with the AI Cost Calculator to estimate spend before you build.
- Prompt trimming — spot when a prompt is getting too long before you hit a hard error from the provider.
Try It Now
Open LLM Token Counter directly from anywhere on the site using ⌘K and typing the tool name. No login required — everything runs offline-capable in your browser.
Part of the AI & Prompt Tools collection on WebdevToolbox — free, browser-based developer tools with no login required.