MB to GB Converter

About MB to GB conversion (SI vs IEC)

MB (megabyte) and GB (gigabyte) are often used as if they mean one single thing, but in practice there are two widely used systems. The decimal or SI system defines 1 GB as exactly 1,000,000,000 bytes (and 1 MB as 1,000,000 bytes). The binary or IEC system defines 1 GiB as 1,073,741,824 bytes (and 1 MiB as 1,048,576 bytes). Storage vendors and many web tools prefer SI because it maps neatly to powers of ten. Operating systems, memory specs, and low-level utilities frequently prefer IEC because it aligns to powers of two. The “missing space” people notice on a new hard drive is usually just the difference between how the label (SI) and the OS (IEC) report the same number of bytes.

Why this tool is trustworthy and fast

This converter calculates everything through bytes, the common language across all unit systems. Your input is parsed, normalized to bytes (integer math to avoid floating-point glitches), and then displayed in MB/GB for SI and in MiB/GiB for IEC, side by side. Because all logic runs locally in your browser, your values are never uploaded. No login, no API, and no server processing — which also means it’s fast, private, and dependable even on slow connections.

Quick rules of thumb you can memorize

• In SI: GB = MB ÷ 1000 and MB = GB × 1000.
• In IEC: GiB = MiB ÷ 1024 and MiB = GiB × 1024.
• If you need to compare apples to apples, convert both values to bytes first.

Popular real-world examples

• 700 MB (SI) is 0.7 GB. In IEC terms the same bytes are ≈ 667.57 MiB or ≈ 0.65 GiB.
• 1024 MB (SI) is 1.024 GB. In IEC it’s ≈ 976.56 MiB or ≈ 0.9537 GiB.
• 1536 MiB (IEC) is exactly 1.5 GiB. In SI that’s ≈ 1.610 GB.

MB vs Mb (byte vs bit) — don’t mix them up

Bandwidth is usually measured in megabits per second (Mb/s or Mbps), while files are measured in megabytes (MB). There are 8 bits in a byte. When you estimate transfer time in this tool, we convert bytes to bits internally, factor in your selected overhead (protocol/real-world losses), and display a human-readable duration. For example, a 2 GB file on a 50 Mbps connection (0% overhead) is roughly: 2 × 1e9 bytes × 8 / (50 × 1e6 bits/s) ≈ 320 seconds, or around 5 minutes and 20 seconds. Real life varies due to Wi-Fi quality, ISP shaping, routing, and concurrent traffic.

When to use SI vs IEC

Use SI when you’re dealing with product labels, web downloads, camera output sizes, and marketing specs for storage (SSDs, HDDs, SD cards). You’ll match what the box says. Use IEC when you compare against what Windows, macOS, or Linux report in system tools, or when you’re measuring RAM and embedded memory. If a coworker says “I only have 465 GB free on my 500 GB drive,” it’s likely because the OS is showing GiB while the drive ships in GB. The bytes are identical; the “unit lens” is different.

Rounding options and significant figures

Different teams prefer different display styles. Finance and procurement might want 2 decimals; engineers might want raw precision. This converter offers multiple modes: No rounding (full precision), 0 dp, 2 dp, and Significant (4 s.f.). The default Auto mode caps most outputs at ≤6 significant digits for readability without hiding material differences. You can switch modes anytime; bytes remain exact internally.

Batch conversions for clean reporting

Managing a spreadsheet of mixed inputs (MB, GB, MiB, GiB) is error-prone. The Batch Mode lets you paste one value per line, normalize everything to bytes, and export a neat CSV that includes SI and IEC columns. This is useful for procurement sheets, media archives, QA checklists, or migration plans where consistency and auditability matter. The “Copy table” button also provides a quick TSV snapshot for pasting directly into Google Sheets or Excel.

File-split planner and transfer-time estimator

Some upload portals cap file sizes (e.g., 100 MB). With the split helper, enter a max part size and you’ll get the required number of parts plus the last part’s approximate size. The transfer-time estimator translates your size into bits, considers Mbps vs MB/s correctly, and applies optional overhead (5–20%) to approximate real-world throughput. This saves guesswork when planning backups, cloud sync, or media deliveries.

Typical file sizes (handy context)

• Smartphone photos (JPEG): 2–8 MB; RAW images: 20–80 MB each.
• 1 minute of 1080p H.264 video (high quality): roughly 100–200 MB (varies by bitrate).
• 1 hour of 4K 60fps video (ProRes): tens to hundreds of GB.
• Modern AAA game installs: 50–150 GB (or more with HD texture packs).
• Office/PDF documents: usually KB to a few MB; scanned PDFs can balloon into hundreds of MB.

Accuracy, privacy, and offline use

All calculations run locally in your browser, so your inputs never leave your device. Because we compute via bytes and avoid unnecessary floating-point steps, outputs are deterministic and repeatable. If you add this page to your browser reading list or install as a PWA (site-wide), it continues to work even with poor connectivity.

Related conversions to explore next

To round out your workflow, consider using additional utilities like KB ⇄ MB, GB ⇄ TB, and MB/s ⇄ Mbps. Linking these tools together improves navigation, encourages deeper sessions, and strengthens topical authority for storage and bandwidth queries.