Duration

Duration is the number of seconds of audio in a sound file. It tells you how long the recording lasts when you play it, not how detailed or clear it sounds. A 2-minute piano piece and a 5-minute piano piece have different durations, even if both were recorded with the same equipment.

If the same sample rate and bit depth are used, a longer duration means more samples are taken in total. Each extra second adds another set of samples, and every sample takes up storage, so the file becomes larger. Doubling the duration doubles the number of samples and the file size, while each second is still captured in the same way.

Duration does not change playback quality. Quality depends on how often the wave is sampled and how many bits store each sample. Adding extra seconds gives you more audio to listen to, but it does not make each second more accurate or less accurate. A long, low-quality clip is still low quality, and a short, high-quality clip is still high quality.

When you use duration in a sound file size calculation, give it in seconds. For example, a clip lasting 3 minutes must be written as 180 seconds; using 3 would make the answer far too small. If a duration is given in minutes, multiply by 60 before putting it into the calculation.