This option lets you control for how long will Nping wait before sending the next probe. Like in many other ping tools, the default delay is one second. <time> must be a positive integer or floating point number. By default it is specified in seconds, however you can give an explicit unit by appending ms for milliseconds, s for seconds, m for minutes, or h for hours (e.g. 2.5s, 45m, 2h).

This option specifies the number of probes that Nping should send per second. This option and --delay are inverses; --rate 20 is the same as --delay 0.05. If both options are used, only the last one in the parameter list counts.