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Video Bitrate Calculator

Solve bitrate, file size, or duration — pick two, get the third.

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How to use Video Bitrate Calculator

  1. Choose what to solve for — Bitrate, File size, or Duration.
  2. Enter the other two values with their units (kbps/Mbps, KB/MB/GB, and HH:MM:SS or seconds).
  3. The answer updates live; copy it with the copy button. Check the reference table for typical bitrate ranges by resolution.

Video Bitrate Calculator

Bitrate, file size, and duration are three faces of one equation:

file size (bits) = bitrate (bits/sec) × duration (seconds)

Know any two and the third is fixed. This calculator solves for whichever one you pick — no spreadsheet, no unit-conversion headaches, all client-side.

Solve for bitrate

The most common case: you have a file and want its average bitrate. Enter the size and the runtime and you get bitrate in both Mbps and kbps. A 100 MB clip that runs 2:00 is 800 megabits over 120 seconds ≈ 6.67 Mbps. This is exactly how "what bitrate is this file" gets answered, and it's the number to compare against a platform's recommended range.

Solve for file size

Planning an encode or an upload and need to predict the output size? Enter the target bitrate and the duration. 5 Mbps for 60 seconds is 5,000,000 × 60 ÷ 8 = 37.5 MB. This is the quick sanity check before you commit to a long export or estimate storage for a batch.

Solve for duration

Given a bandwidth or storage budget, how long can the video be? Enter a size cap and a bitrate and get the maximum runtime. Useful for fitting content into an upload limit or a fixed-size medium.

Decimal units, on purpose

Everything here is decimal (SI): 1 MB = 1,000,000 bytes, 1 Mbps = 1,000,000 bits/second. That matches how encoders, cameras, and streaming platforms quote numbers. Your operating system may report file sizes in binary units (MiB/GiB, powers of 1024), which is why a "1 GB" file can show as ~0.93 GiB. For bitrate planning, decimal is the right frame — mixing the two is a classic source of "why is my math 7% off" confusion.

Bitrate vs quality

A calculator gives you the arithmetic, not the aesthetic. The right bitrate depends on codec, content, and frame rate:

  • Codec. H.265 (HEVC) and AV1 hit the same visual quality as H.264 at roughly half to two-thirds the bitrate. The table in the tool assumes H.264 — scale down for newer codecs.
  • Motion. Fast action, grain, and confetti need more bits than a talking head. Constant-bitrate (CBR) encodes to a fixed number; variable-bitrate (VBR) and constant-quality (CRF) let it float to match complexity.
  • Frame rate. 50/60 fps needs roughly double the bitrate of 24/30 fps for equivalent quality.

Use the reference table as a starting point, then verify with your eyes on real footage.

Typical H.264 bitrate ranges

Resolution Bitrate (Mbps)
480p (SD) 1.0 – 2.5
720p (HD) 2.5 – 5
1080p (Full HD) 5 – 10
1440p (2K) 10 – 20
2160p (4K) 25 – 50

These are encode/upload targets at standard frame rates, not hard limits. For live-streaming upload targets and platform caps, use the Streaming Bitrate Calculator; to break a target size into separate audio and video bitrates, use the Video File Size Calculator.

Frequently asked questions

How do I calculate video bitrate from a file size?

Bitrate = file size in bits ÷ duration in seconds. A 100 MB clip is 800,000,000 bits; over 120 seconds that's about 6.67 Mbps. Enter the size and duration and this tool does it, including the KB/MB/GB and kbps/Mbps conversions.

What's the relationship between bitrate, file size, and length?

They form one equation — file size (bits) = bitrate (bits/sec) × duration (sec). Fix any two and the third is determined. That's why a longer video or a higher bitrate both grow the file linearly.

Are these megabytes decimal (1,000,000) or binary (1,048,576)?

Decimal (SI). 1 MB = 1,000,000 bytes and 1 Mbps = 1,000,000 bits/s. That's the convention encoders, streaming platforms, and bitrate math use. If your OS reports binary MiB, expect a ~5% difference at the GB scale.

What bitrate should I use for 1080p?

As a rule of thumb, 5–10 Mbps for 1080p at 24–30 fps with H.264, higher for fast motion or 50/60 fps, lower with H.265/AV1 for the same quality. See the reference table in the tool — but always let a quality target, not a fixed number, drive the final encode.

Why is my streaming upload bitrate different from the file bitrate?

A stored file's bitrate is its average over the whole clip. Live streaming uses a target (often capped) bitrate plus a separate audio bitrate, and platforms enforce their own ceilings. Use the Streaming Bitrate Calculator for upload/bandwidth planning.

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