SpanD is a free tool for calculating DateTime intervals and finding the difference between two specified dates. This is a fully online app and works on any device with a modern browser (including mobile phones) however, has no guarantee of working on the latest browser's version as it is being not supported anymore. You can enter the dates either as plain text or by using the built-in date picker. You can also specify the interval by using a slider. In case of a missing interval, the app will calculate it automatically. You can enter the dates either in the form of a string or as an array of two numbers. The app is useful to calculate the span between two dates or for finding the next or previous date, depending on the current date.