Xfinity Data Cap Calc is a free Chrome extension developed by ceiyne9. This add-on helps Xfinity customers monitor and project their data usage to avoid exceeding their monthly data cap. Once installed, the extension provides additional information when checking data usage on the Xfinity customer service portal.

With Xfinity Data Cap Calc, users can easily view the amount of data they have used in both gigabytes and as a percentage of their total cap for the current month. The extension also calculates how many days' worth of data have been used based on the average amount allowed per day under the cap. Additionally, it projects the amount of data that will be used if the current rate of usage continues for the rest of the month.

While the extension's authors have made efforts to ensure accurate calculations, unforeseen errors may occur. It is important to note that projected calculations are based on the current rate of data usage, which may change over time and may not be entirely accurate. The authors of Xfinity Data Cap Calc are not responsible for any issues that may arise from its use, including data cap fees.