What's the difference between KB and KiB (decimal vs binary)?

KB (kilobyte) in decimal means 1,000 bytes following metric system, while KiB (kibibyte) in binary means 1,024 bytes based on powers of 2 (2^10). This causes confusion: a 500 GB hard drive contains 500 billion bytes but Windows shows ~465 GB because it calculates in binary (GiB) then mislabels as GB. The IEC standardized distinct symbols in 2008: KB/MB/GB (×1000) vs KiB/MiB/GiB (×1024). This converter uses decimal (×1000) matching international SI standards and storage marketing. The 'missing' storage isn't lost—it's measurement confusion. 1 GB = 1,000 MB = 1,000,000 KB = 1 billion bytes (decimal). 1 GiB = 1,024 MiB = 1,048,576 KiB = 1,073,741,824 bytes (binary, 7% more than decimal GB).

How many MB in a GB and why does my drive show less space?

In decimal: 1 GB = 1,000 MB = 1,000,000 KB. In binary: 1 GiB = 1,024 MiB. The 'missing space' phenomenon occurs because: (1) Manufacturers advertise decimal (1 TB = 1 trillion bytes), (2) Operating systems calculate binary (1 trillion bytes ÷ 1024³ = 931 GiB), (3) OS then mislabels GiB as GB, showing '931 GB' for a '1 TB' drive. You lose ~7% per conversion level: 1 TB drive shows as 931 GB, 500 GB shows as 465 GB, 256 GB shows as 238 GB. This is legal and standardized—manufacturers follow SI metric system. Additionally, some space is used for formatting (1-3%) and hidden recovery partitions (10-20 GB). To calculate actual usable space: take advertised size, multiply by 0.931, subtract 10-30 GB for system overhead. A '1 TB' laptop has ~900 GB usable after OS installation.

What file sizes should I expect for different types of files?

IMAGES: Phone photo (JPEG) 2-8 MB, RAW camera photo 25-50 MB, PNG screenshot 0.5-3 MB, high-res artwork 10-100 MB. AUDIO: MP3 song (4 min) 4-8 MB, FLAC lossless 30-50 MB, podcast episode (1 hour) 50-100 MB. VIDEO: 1080p movie (2 hours) 4-8 GB, 4K movie 25-50 GB, 1-min phone video 100-300 MB, YouTube video (10 min 1080p) 200-500 MB. DOCUMENTS: Text document 10-100 KB, PDF with images 1-10 MB, PowerPoint presentation 5-50 MB, Excel spreadsheet 100 KB - 10 MB. SOFTWARE: Mobile app 50-500 MB, PC game 20-150 GB (AAA titles), Windows OS 20-30 GB, macOS 30-40 GB. STORAGE NEEDS: Casual user 256 GB sufficient, photographer 1-2 TB, video editor 4-8 TB, gamer 1-2 TB. Cloud storage: Google Photos unlimited compressed, Dropbox 2 GB free, iCloud 5 GB free. Understanding typical sizes helps plan storage, estimate download times, and choose appropriate file formats.

How long does it take to download different file sizes?

Download time = File size ÷ Connection speed. Internet speeds: Slow (5 Mbps), Moderate (25 Mbps), Fast (100 Mbps), Very fast (500 Mbps), Gigabit (1000 Mbps). Note: Mbps = megabits/sec, MB = megabytes, 8 bits = 1 byte. 100 MB FILE: 5 Mbps = 2.7 minutes, 25 Mbps = 32 seconds, 100 Mbps = 8 seconds, 1 Gbps = 0.8 seconds. 1 GB FILE: 5 Mbps = 27 minutes, 25 Mbps = 5.3 minutes, 100 Mbps = 1.3 minutes, 1 Gbps = 8 seconds. 10 GB GAME: 5 Mbps = 4.4 hours, 25 Mbps = 53 minutes, 100 Mbps = 13 minutes, 1 Gbps = 80 seconds. 50 GB 4K MOVIE: 5 Mbps = 22 hours, 25 Mbps = 4.4 hours, 100 Mbps = 1.1 hours, 1 Gbps = 6.7 minutes. PRACTICAL TIPS: Test your speed at speedtest.net. Downloads often slower than advertised (network congestion, server limits). WiFi typically 30-50% slower than wired. Multiple devices sharing bandwidth divide speed. Streaming doesn't require full download: 4K Netflix needs 25 Mbps sustained, 1080p needs 5 Mbps.

What storage capacity do I need for different uses?

SMARTPHONES: Basic user (photos, apps, music): 64-128 GB. Heavy user (many apps, offline content): 256-512 GB. Pro (4K video, photography): 512 GB - 1 TB. LAPTOPS: Office work (documents, email, web): 256 GB SSD. Student (documents, some media): 512 GB. Creative professional (Photoshop, video): 1-2 TB. Gamer: 1-2 TB (AAA games are 50-150 GB each). EXTERNAL DRIVES: Photo backup: 1-2 TB. Video archive: 4-8 TB. Complete media server: 10-20 TB. Time Machine backup: 2-3× your internal drive. CLOUD STORAGE: Basic backup: 100-200 GB. Photo library: 500 GB - 1 TB. Everything: 2-5 TB. PHOTOGRAPHY: Casual (JPEGs): 100 GB/year. Enthusiast (some RAW): 500 GB/year. Pro (all RAW): 2-5 TB/year. VIDEO EDITING: 1080p projects: 500 GB - 1 TB. 4K projects: 4-8 TB. RULE OF THUMB: Buy 50-100% more than you think you need—files accumulate. SSDs for speed (OS, apps), HDDs for bulk storage (photos, videos). Monitor storage monthly: macOS Storage Management, Windows Storage Sense.

What's the difference between storage capacity and actual usable space?

Advertised capacity never equals usable space due to: (1) DECIMAL vs BINARY: 1 TB = 1 trillion bytes (advertised), but OS shows 931 GB (binary calculation) = 6.9% reduction. (2) FILE SYSTEM OVERHEAD: Formatting creates file allocation tables, metadata structures, journaling space = 1-3% overhead. NTFS (Windows) uses ~1%, APFS (Mac) ~2%, ext4 (Linux) ~1%. (3) HIDDEN PARTITIONS: Recovery partition (10-20 GB on Windows laptops), EFI/boot partition (100-500 MB), OEM bloatware partition (5-15 GB). (4) OPERATING SYSTEM: Windows 10/11 requires 20-30 GB, macOS 30-40 GB, Linux 10-20 GB. (5) PAGE/SWAP FILE: Windows reserves space equal to RAM (8-16 GB typically). REAL EXAMPLE: '1 TB' laptop advertised → 931 GB after binary conversion → 20 GB hidden recovery partition → 30 GB Windows installation → 10 GB page file = ~870 GB usable (13% loss). External drives lose less: no OS, no hidden partitions, only binary difference = ~93% usable. To calculate YOUR usable space: (Advertised GB × 0.931) - (OS size + hidden partitions) = realistic expectation. This isn't false advertising—it's industry-standard SI measurement meeting real computing overhead.

How do file compression and formats affect file sizes?

COMPRESSION TYPES: Lossless (perfect quality, larger files) vs Lossy (quality loss, much smaller files). IMAGES: RAW (uncompressed, 25-50 MB) → TIFF (lossless, 20-40 MB) → PNG (lossless, compressed, 2-10 MB) → JPEG high quality (lossy, 3-8 MB) → JPEG medium (1-3 MB) → WebP (Google's format, 30% smaller than JPEG). Same photo can range 2-50 MB depending on format. DOCUMENTS: DOCX (Office 2007+) is compressed XML, 10-50% smaller than DOC. PDF compression varies: scanned PDFs (large, 1-5 MB/page), text PDFs (small, 50-200 KB/page). VIDEO: RAW video (massive, 1 GB/minute) → ProRes/DNxHD (intermediate, 100-300 MB/min) → H.264 (standard, 10-30 MB/min) → H.265/HEVC (next-gen, 50% smaller than H.264). 4K movie: 200 GB uncompressed → 25-50 GB Blu-ray → 4-8 GB Netflix stream. AUDIO: WAV (uncompressed, 10 MB/min) → FLAC (lossless, 3-5 MB/min) → MP3 320kbps (2.4 MB/min) → MP3 128kbps (1 MB/min). ZIP COMPRESSION: Text files compress 50-90%, images/videos barely compress (already compressed). CHOOSING FORMAT: Archival/editing = lossless (RAW, TIFF, FLAC, ProRes). Sharing/web = lossy (JPEG, MP3, H.264). Balance quality vs size needs.

What are bytes, and how do they relate to computer data?

BYTE = fundamental unit of computer storage, consisting of 8 bits. One byte can represent 256 different values (2^8), typically used for one text character in ASCII encoding. HIERARCHY: 1 bit = smallest unit (0 or 1). 8 bits = 1 byte (can store values 0-255). 1024 bytes = 1 KB (kilobyte). 1024 KB = 1 MB (megabyte). 1024 MB = 1 GB (gigabyte). 1024 GB = 1 TB (terabyte). 1024 TB = 1 PB (petabyte). REAL-WORLD SCALE: 1 byte = 1 character ('A' = 1 byte). 10 bytes = 1 word. 100 bytes = 1 sentence. 1 KB = 1 paragraph (500-1000 characters). 1 MB = 1 small book (500 pages) or 1 minute of MP3 audio. 1 GB = 1,000 small books or 1 hour video or 250 MP3 songs. 1 TB = 1 million books or 500 hours HD video or library of 200,000 songs. COMPANY DATA: Google processes 20+ PB daily, Facebook stores 300+ PB of photos, Amazon S3 stores exabytes (1 EB = 1,000 PB = 1 million TB). HUMAN BRAIN: Estimated 2.5 PB storage capacity (debated). Understanding bytes helps estimate storage needs: if your average photo is 5 MB, a 256 GB phone holds ~51,000 photos (accounting for OS overhead).

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File Size Converter

Convert file size between Bytes, KB, MB, GB, and TB

File Size Converter

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What is File Size Converter?

A file size converter translates between digital storage units including bytes, kilobytes (KB), megabytes (MB), gigabytes (GB), terabytes (TB), and petabytes (PB), handling both decimal (1000-based) and binary (1024-based) conversions. Essential for understanding storage capacity, comparing cloud storage plans, estimating download times, managing disk space, and comprehending file sizes reported by different systems that use different measurement standards. Converts between units used by operating systems, hard drive manufacturers, cloud providers, and networking specifications.

Key Benefits & Use Cases

Understand actual storage capacity when buying hard drives or cloud storage—manufacturers use decimal GB (1000 MB) while operating systems use binary GiB (1024 MB), creating apparent capacity loss that is actually just measurement differences. Estimate download times accurately by converting file sizes to megabits/gigabits for comparison with internet speeds measured in Mbps or Gbps. Compare storage plans apples-to-apples across providers who may quote capacity in different units. Manage disk space effectively by understanding how many photos, videos, or documents fit within available storage. Calculate whether files fit on USB drives, email attachment limits, or upload restrictions. Used by IT professionals, content creators, cloud storage users, and anyone managing digital files.

How to Use This Calculator

Enter file size value and select the source unit (bytes, KB, MB, GB, TB, PB). Results instantly display equivalent values in all other units using both decimal (1000-based, used by storage manufacturers) and binary (1024-based, used by operating systems) calculations. For decimal, 1 KB = 1000 bytes; for binary, 1 KiB = 1024 bytes. Use decimal for hard drive capacities, cloud storage, and networking; use binary for RAM and file sizes reported by operating systems. Common conversions: 1 GB = 1000 MB (decimal) or 1024 MiB (binary). Understanding both standards explains why a "500 GB" hard drive shows as "465 GB" in Windows—different measurement systems, not missing space.