The Three Phases of a Conversion
Upload depends on your internet connection's upstream speed and the file size- A 10 MB file takes a couple of seconds on office broadband and noticeably longer on hotel Wi-Fi. Conversion happens on our servers: a 5-minute song converts to MP3 in roughly 2-5 seconds, and even an hour-long recording usually finishes in under half a minute. Download is generally the fastest phase, because MP3 output is smaller than most sources. In practice, for anything but tiny files, the upload is the long pole- Which is why a slow conversion on mobile data is almost never actually slow conversion.
What Makes Some Jobs Slower
Three things add real processing time. Duration: conversion time scales with audio length, not file size, so a 3-hour lecture takes longer than a 4-minute song even at the same size. Video sources: extracting audio from MP4, MKV, or MOV means the server reads through a much larger file, and the upload itself is bigger. Complex sources: dense lossless formats like FLAC or APE decode slightly slower than lossy ones. Output bitrate, by contrast, barely matters- 128 kbps and 320 kbps take almost the same time.
Batches and Busy Periods
Files in a batch convert in parallel, so a 10-file batch typically finishes only a little after a single file would- Limited mostly by how long the whole upload takes. During rare peak-traffic periods jobs may queue briefly before starting; you will see the file marked as waiting rather than converting. Paid-plan jobs are prioritized in the queue, but on a normal day guests and subscribers see effectively identical speeds- There is no artificial slowdown on the free tier.
If a Conversion Seems Stuck
First check the phase: a stalled progress bar during upload points to your connection- Try again on a steadier network. If the upload completed but the conversion has shown no progress for several minutes, refresh the page; your file is still on the server and the status will update. A file that repeatedly fails is usually either over the size limit for your plan or corrupted (test whether it plays locally). If a healthy, in-limit file still will not convert, contact support with the format, size, and approximate time of the attempt.