💾 File Size Converter
Convert between bytes, kilobytes, megabytes, gigabytes, and terabytes.
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How Digital File Sizes Work
Digital storage is measured in powers of 2: 1 kilobyte (KB) = 1,024 bytes, 1 megabyte (MB) = 1,024 KB = 1,048,576 bytes, 1 gigabyte (GB) = 1,024 MB, and 1 terabyte (TB) = 1,024 GB. These binary-based measurements reflect the underlying architecture of digital memory. This contrasts with the way some storage manufacturers use "gigabyte" to mean exactly 1,000,000,000 bytes, which is why a "500 GB" hard drive shows as approximately 465 GB in your operating system.
Internet speed is measured in bits (lowercase "b"), not bytes (uppercase "B"). The key relationship: 8 bits = 1 byte. So a 100 Mbps internet connection transfers 100 megabits per second, which equals 12.5 megabytes (MB) per second. This is why a 100 MB file doesn't download in 1 second on a 100 Mbps connection — it takes approximately 8 seconds. For practical download time estimates, use the Internet Speed Calculator on CalForge.
Common file size reference: a typical photo from a modern smartphone is 3–10 MB. A one-minute HD video at 1080p is approximately 100–150 MB. A two-hour 4K movie can be 50–100 GB. A music track in MP3 format at 128 kbps is approximately 1 MB per minute. A PDF document with text and images is typically 0.5–5 MB. A modern game like Call of Duty or FIFA can exceed 100 GB installed.
Email attachments: most email services limit attachments to 25 MB per email (Gmail, Outlook). Files larger than this should be shared via cloud storage (Google Drive, Dropbox, OneDrive) with a shared link. When sending large files internationally or to clients, compressing files (ZIP format) can reduce size by 50–70% for uncompressed formats like BMP images or WAV audio, though JPEG, MP4, and PDF files compress very little since they're already compressed.
Cloud storage planning: if you're choosing a backup or cloud storage plan, convert your estimated storage needs to GB before comparing plan sizes. 1,000 photos ≈ 5–10 GB. A year of music ≈ 5–15 GB. A personal document archive ≈ 1–5 GB. A media library with videos ≈ 100 GB+.
Understanding Digital File Sizes
Digital file size is measured in bits and bytes. 8 bits = 1 byte. 1,000 bytes = 1 kilobyte (KB). 1,000 KB = 1 megabyte (MB). 1,000 MB = 1 gigabyte (GB). Note: computers sometimes use binary prefixes (kibibyte = 1,024 bytes) rather than decimal, which is why a 1GB USB drive shows less available space than expected.
File size matters for storage capacity planning, upload/download time estimation, email attachment limits, and data transfer costs. Larger files take longer to upload and download and consume more storage space.