Digital Storage Converters
Last updated: 2 June 2026
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Guide
Understanding Data Sizes and Internet Speeds
Your phone plan says "unlimited data" but also mentions "5GB per month". Your cloud storage shows file sizes in MB. Your internet provider promises "NBN 50 Mbps". These numbers look related, but they're measuring completely different things, and confusion costs you real money.
Start with the basics. A byte is the smallest common unit. One kilobyte (KB) is 1,000 bytes (roughly). A megabyte (MB) is 1,000 kilobytes. A gigabyte (GB) is 1,000 megabytes. A terabyte (TB) is 1,000 gigabytes. You need this because storage capacity and file sizes both use these units, and they're critical for deciding what phone plan you actually need.
Phone plans are where this gets Australian-specific. When Telstra or Vodafone offers "10GB per month", you're burning through that 10 gigabytes when you stream Netflix, scroll Instagram, or download emails. High-definition video uses roughly 3GB per hour. A typical music stream uses about 5MB per song. If you're commuting an hour each way and streaming Spotify, that's eating 10-15GB per month just on audio. Add social media scrolling and you'll see why 10GB isn't actually unlimited.
Internet speed is where the biggest mistake happens. When your NBN provider advertises "50 Mbps", that's 50 megabits per second, not megabytes. One byte equals 8 bits. So 50 Mbps actually means roughly 6.25 megabytes per second download. This matters because a 1GB file takes around 160 seconds (about 2.5 minutes) on a 50 Mbps connection, not 20 seconds like people often guess. The gap between Mbps (marketing number) and MB/s (actual download speed) has confused Australians since ADSL.
Storage capacity is different again. A 1TB external hard drive doesn't actually hold exactly 1,000 gigabytes once you format it. Manufacturers use "1 trillion bytes" (base 10), while computers count in binary (base 2). You lose roughly 93 gigabytes of usable space on a 1TB drive. This annoys people, but it's industry standard. If you're buying cloud storage (Dropbox, Google One, iCloud), check the fine print. Apple advertises 200GB but you only get 200GB of actual usable space because they use marketing measurements.
When sizing your needs, work backwards. Photo backups? A 12-megapixel photo is roughly 3-4MB. A year of daily photos is about 1.5GB. Video? That 4K recording from your holiday is 100MB per minute. Plan accordingly. For internet speed, Netflix recommends 25 Mbps for 4K (that's 3 MB/s), but Australian networks often drop speed during peak hours, so don't count on your full plan speed at dinner time.
Common Questions
Why does my 1TB hard drive say only 931GB available?
Hard drive manufacturers use base 10 (1 trillion bytes = 1TB), but computers calculate in base 2 (binary). The difference costs you about 93GB per terabyte. It's not broken, it's just how the industry labels things. SSDs have the same issue.
My internet is "50 Mbps" but only downloads at 6 MB/s. Am I being scammed?
No. Mbps means megabits, and 50 megabits = 6.25 megabytes per second. One byte equals 8 bits. Check your contract, and you'll see they advertise in megabits (the smaller number). ISPs do this intentionally because it sounds faster.
How much data does streaming actually use?
Netflix in HD is roughly 3GB per hour. Spotify is about 5MB per song. YouTube varies from 300MB per hour (480p) to 2.7GB per hour (1080p). A typical work Zoom call is 1-2MB per minute depending on camera quality. Work backwards from your plan to see what you can actually do.
What phone plan data do I actually need?
Light use (email, maps, messaging): 2-5GB. Moderate use (social media, some video): 10-15GB. Heavy use (daily streaming, video calls): 30GB+. If you're home on WiFi most days, you need less. Don't pay for unlimited unless you genuinely stream 4K video daily.
Is KB/MB/GB different from Kibit/Mebit/Gigabit?
Yes. KB is kilobyte (8 kilobits). Kilobit is usually abbreviated Kb or Kbit. In internet speeds, ISPs always quote megabits (Mbps), not megabytes. If you see "Mb" it means bits. If you see "MB" it means bytes (8 times larger).
How do I estimate download time?
Divide file size (in MB) by your speed (in MB/s), then convert to seconds. Example: 500MB file on 5 MB/s connection = 100 seconds. Or multiply file size in gigabytes by 8, then divide by your Mbps speed. A 2GB file on 50 Mbps takes (2 times 8) divided by 50 = 0.32 minutes, about 19 seconds.
How We Verify Our Conversions
Every converter on RefDat uses peer-reviewed conversion factors sourced from the International Bureau of Weights and Measures (BIPM), the National Institute of Standards and Technology (NIST), and the Australian National Measurement Institute (NMI). Temperature formulas follow the ITS-90 international temperature scale. Cooking measurements use Standards Australia definitions (AS 1766) where applicable. We cross-check against multiple authoritative sources and test every calculator both forwards and backwards before publishing. If you spot an error, let us know.