Paste your system prompt into most token counters and you get a number. That’s it. A number.
This one does something more useful. A developer just shipped a browser-only counter that doesn’t just count; it tells you exactly where you’re bleeding tokens and why.
Here’s the twist: nothing you paste ever leaves your browser. Which makes it the rare online tool you can actually run production system prompts through without a second thought.
Here’s what it surfaces beyond the raw count:
- 🔢 Exact token counts for OpenAI (labeled estimates for other providers)
- 💰 Cost per request AND per month; so you see the real bill before it hits
- ⚠️ Context-window pressure indicator
- 🔥 A heatmap showing which regions of your prompt are token-dense
- Optimization flags: repeated lines, markdown table overhead, bloated structure
That last part is where it gets useful. Redundant lines and over-formatted tables are quiet token sinks that pile up across millions of calls.
How to use it in 2 minutes
- Go to freetokencounter.com
- Paste your prompt (system message, user template, whatever you’re paying to send)
- Check the heatmap first; dense regions are your low-hanging fruit
- Hit the Optimize tab for specific flags
- Trim, re-paste, watch the cost estimate drop
Pro tip: Run your current production system prompt through this before your next deployment. Trimming even 200 tokens at 1M requests a month adds up faster than you’d expect.
If you’re writing prompts at any kind of scale, this deserves a bookmark. 🔖
Try it: freetokencounter.com
I built a free, browser-only token counter with prompt optimization signals — feedback wanted
by u/Livid-Calendar-3307 in PromptEngineering