Podcast File Size & Episode Length Calculator
Estimate your MP3 file size from length and bitrate, and convert a script word count into speaking time. Free, instant, no sign-up.
Episode file size
Estimate the MP3 size from length and bitrate.
Estimated file size
43 MB
≈ 0 GB · 1 MB per minute at 128 kbps
Script speaking time
Estimate how long a script takes to read aloud.
Slow 110 · Conversational 150 · Fast 180 wpm
Estimated speaking time
40 min
40 minutes at 150 words per minute
How the maths works
File size. Audio at a constant bitrate uses a fixed number of bits per second, so size grows linearly with length. In bytes that is bitrate(bps) × seconds ÷ 8. Expressed in the megabytes podcast hosts quote, the shortcut is kbps × minutes × 0.0075.
Speaking time. Divide your word count by your speaking pace. Around 150 words per minute is typical for conversational podcasting, so the same script reads faster or slower as you adjust the pace.
Figures are estimates — real exports vary slightly with variable-bitrate encoding, intro/outro music, and pauses.
Frequently asked questions
How do you calculate a podcast MP3 file size?
Multiply the audio bitrate in kilobits per second by the duration in seconds, then divide by 8 to convert bits to bytes. As a shortcut, file size in megabytes ≈ bitrate (kbps) × length (minutes) × 0.0075. For example, a 60-minute episode at 128 kbps is about 57.6 MB.
What bitrate should I export my podcast at?
For spoken-word podcasts, 96–128 kbps gives clear voice with small files. Use 64 kbps mono for the smallest size, or 192–320 kbps when music quality matters. 128 kbps is the most common standard for podcasts.
How long will my podcast script take to read aloud?
Divide your word count by your speaking pace. Most podcasters speak around 150 words per minute, so a 6,000-word script runs roughly 40 minutes. Slower, more deliberate delivery is closer to 110 wpm; fast delivery reaches about 180 wpm.
Does a longer episode always mean a bigger file?
Yes — at a fixed bitrate, file size grows linearly with length. To keep files small for listeners on limited data, lower the bitrate (e.g. 64–96 kbps for voice) rather than trimming content.
Is this podcast calculator free?
Yes. It runs entirely in your browser, needs no sign-up, and stores nothing. GeraCast also offers free AI transcription, show notes, and one-click distribution to Spotify, Apple Podcasts and more.
Keep going with GeraCast
Part of Gera Systems — see also GeraCompliance and GeraQuest.