IconVault's API Rate Calculator does the rate-limit math for you: enter your limit and period, pick token bucket or sliding window, add your expected traffic, and get requests/day capacity, utilization, headroom, a burst verdict, and a tier-planning checklist. It even generates a copy-paste token-bucket implementation filled with your exact numbers.

Whether you are designing API pricing tiers or just trying not to get 429s, the calculator shows where your limit breaks before your users do. Free and runs fully in your browser.