Video Space Calculator
This tool is intended to give an indication of the amount of space a given video format will take up on disk. The actual space taken up may differ slightly due to embedded audio, differing frame sizes and aspect ratios, and inter-frame compression / pulldown.
Link to this calculation
Note: VBR codecs adjust the data rate based on the source footage so the file sizes listed are a result of the maximum or target data rates. Actual data sizes will be 5-10% lower for VBR codecs.