Video File Size Calculator

1. Choose whether to solve for file size or for bitrate.
2. Enter the bitrate, or a target file size, depending on the mode.
3. Enter the duration of the video.
4. Read the result, plus the size per minute and per hour.

Here is what each result means:

Bitrate is how much data a video uses each second, measured in megabits per second, or Mbps. It is the main thing that controls both quality and file size.

A higher bitrate stores more detail, giving a sharper picture, but it makes the file bigger. A lower bitrate saves space but can look blocky. Resolution, frame rate, and how much the scene moves all influence the bitrate a video needs.

File size is simply the data rate multiplied by how long the video runs. The only care needed is with units, since bitrate is in bits but file size is in bytes, and one byte is eight bits.

1. Convert the duration to seconds.
2. Multiply the bitrate in Mbps by the seconds.
3. Divide by 8 to turn megabits into megabytes.

To find a bitrate instead, the calculator runs the formula in reverse: it multiplies the target size by 8 and divides by the duration in seconds.

Estimate the size of a 30 minute video recorded at 8 Mbps.

Calculation: 30 minutes is 1,800 seconds. Multiplying 8 Mbps by 1,800 seconds gives 14,400 megabits. Dividing by 8 gives 1,800 megabytes, which is about 1.8 GB. That works out to roughly 60 MB for every minute of video.

These are common streaming and recording ranges. Actual bitrates vary with codec, frame rate, and content.

Many platforms and email tools cap file size. To fit a limit, switch the calculator to bitrate mode, enter the size cap and the video length, and it gives the highest bitrate that fits.

Set your encoder to that bitrate or a little below, to leave room for the audio track and container overhead. A lower bitrate trades some quality for a smaller file.

Planning Storage

Work out how many hours of footage will fit on a memory card or drive before you record.

Staying Under Upload Limits

Find the bitrate that keeps a clip under an email or platform size cap without guessing.

Estimating Data Use

See how much mobile data streaming or uploading a video will use, so you avoid surprise charges.

1. Confusing Megabits and Megabytes

Bitrate uses megabits (Mb), while file size uses megabytes (MB). Since one byte is eight bits, forgetting to divide by 8 overstates the size eightfold.

2. Ignoring the Audio Track

This tool estimates the video stream. Audio adds a little more, often 128 to 320 kbps, so real files run slightly larger.

3. Assuming Resolution Sets the Size

Two 1080p videos can differ greatly in size if their bitrates differ. Bitrate, not resolution alone, drives the file size.

4. Forgetting Variable Bitrate

Many videos use variable bitrate, so the real size can differ from an estimate based on one average number.

The math is exact for a constant bitrate. Real files vary because of variable bitrate encoding, audio, and container overhead.

Multiply the bitrate in Mbps by the duration in seconds, then divide by 8 to convert megabits to megabytes. A 30 minute video at 8 Mbps is about 1,800 MB, or 1.8 GB.

Bitrate is how much data a video uses per second, in megabits per second. A higher bitrate means more detail and a larger file; a lower bitrate saves space but can reduce quality.

Full HD 1080p video typically uses 5 to 10 Mbps for streaming, and higher for recording. The exact figure depends on frame rate, codec, and how much motion the footage has.

Mbps is megabits per second, used for bitrate. MBps, or MB, is megabytes, used for file size. One byte is eight bits, so you divide the bitrate by 8 to find the size.

Lower the bitrate, shorten the video, or use a more efficient codec. Switch this calculator to bitrate mode to find the highest bitrate that keeps the file under your size limit.

No. Bitrate decides file size. Two 1080p videos can be very different sizes if one uses a higher bitrate, since resolution only sets the pixel grid, not the data rate.

No. The estimate covers the video stream only. Audio usually adds 128 to 320 kbps, so real files are a little larger than the video-only figure shown here.

No. The calculation runs in your browser and nothing you enter is stored or sent anywhere, unless you choose Save, which keeps the result only on this device.

• Bit rate (general reference).
• Megabyte and bit-to-byte units (general reference).