What is the difference between binary and decimal storage?

Binary uses powers of 1024 (used by operating systems and RAM). Decimal uses powers of 1000 (used by hard drive manufacturers). A 1 TB drive (decimal) shows as about 931 GiB in your OS (binary). The bytes are identical; only the labels differ.

Why does my hard drive show less space than advertised?

Hard drive manufacturers use decimal units (1 TB = 1,000,000,000,000 bytes) while operating systems display in binary units (1 TiB = 1,099,511,627,776 bytes) but typically still label them "TB". The actual storage capacity matches the spec; the OS just measures it with a different unit. The gap grows: 9% at TB, 11% at PB.

How many photos can 1 GB hold?

At typical smartphone photo sizes (3-5 MB each), 1 GB can hold roughly 200-330 photos. RAW photos from a DSLR (25-50 MB each) would fill 1 GB with only 20-40 images. iPhone HEIC photos are smaller (1.5-3 MB) so you can fit 350-650 per GB.

What does KiB, MiB, GiB mean?

These are the IEC binary prefixes introduced in 1998 to disambiguate from SI decimal prefixes. KiB = kibibyte = 1024 bytes. MiB = mebibyte = 1024² = 1,048,576 bytes. GiB = gibibyte = 1024³. TiB = tebibyte = 1024⁴. Linux and many technical tools use these; Windows still uses KB/MB/GB to mean binary values.

Is RAM measured in binary or decimal?

RAM is always binary. "8 GB RAM" means 8 × 2³⁰ = 8,589,934,592 bytes. RAM chips are addressed by physical lines, which scale in powers of 2 (a 30-bit address bus addresses exactly 1 GiB). The "GB" label is technically incorrect but universally used.

How big is a petabyte?

1 PB = 10¹⁵ bytes = 1,000 TB = 1,000,000 GB. To visualize: ~250 million photos, ~13 years of HD video, or 500 billion pages of text. Hyperscale cloud providers operate at exabyte (1,000 PB) scale; Facebook stored 1 EB of photos by 2019. Most companies don't cross PB until they're storing video at scale.

How much storage does a typical 1080p movie use?

Compressed for streaming (Netflix, H.264): 4–8 GB for a 2-hour film. Blu-ray rip (H.264 high-bitrate): 15–25 GB. 4K UHD Blu-ray (HEVC/H.265): 50–100 GB. Raw uncompressed 1080p video: ~700 GB per hour. Compression ratios of 100:1 are common for delivery codecs.

Data Storage Converter

Quickly convert data storage units between bytes, kilobytes, megabytes, gigabytes, terabytes, and petabytes. Supports both binary (1024-based) and decimal (1000-based) conversions.

Last updated: May 28, 2026

About this calculator

Data storage units look simple — kilobyte, megabyte, gigabyte, terabyte — but there's a six-decade-old fight underneath them. Computer scientists defined them in base 2 (1 KB = 1,024 bytes), because that's the natural unit when memory is addressed in powers of 2. Marketing and the metric system defined them in base 10 (1 KB = 1,000 bytes), because that's what "kilo" means in SI. Both standards now coexist, and the resulting confusion is why a "1 TB" external drive shows as ~931 GB in your operating system: the drive maker used decimal, your OS uses binary.

The IEC tried to fix this in 1998 with new names — kibibyte (KiB), mebibyte (MiB), gibibyte (GiB), tebibyte (TiB) — explicitly meaning the binary powers (1024, 1024², 1024³, 1024⁴). The new names never caught on in everyday speech, but they're how the IEC, ISO, IEEE, and Linux distributions write it precisely. This converter handles both standards so you can translate between what a vendor advertises and what your machine actually shows.

Beyond the binary-vs-decimal headache, this calculator is useful any time you need to size storage budgets, estimate file counts at a given resolution, or convert between units that span eight orders of magnitude (bytes to petabytes). Once you internalize the powers of 2 (1024² = 1 MiB, 1024³ = 1 GiB), most conversions become mental arithmetic.

Formula

**Binary (IEC standard, used by OS and RAM):** | Unit | Power of 2 | Bytes | |---|---|---| | 1 KiB | 2¹⁰ | 1,024 | | 1 MiB | 2²⁰ | 1,048,576 | | 1 GiB | 2³⁰ | 1,073,741,824 | | 1 TiB | 2⁴⁰ | 1,099,511,627,776 | | 1 PiB | 2⁵⁰ | 1,125,899,906,842,624 | **Decimal (SI standard, used by storage marketing and bandwidth):** | Unit | Power of 10 | Bytes | |---|---|---| | 1 KB | 10³ | 1,000 | | 1 MB | 10⁶ | 1,000,000 | | 1 GB | 10⁹ | 1,000,000,000 | | 1 TB | 10¹² | 1,000,000,000,000 | | 1 PB | 10¹⁵ | 1,000,000,000,000,000 | **Conversion ratios between standards (the "size shrinkage"):** | Quantity | Decimal/Binary ratio | Effective shrinkage | |---|---|---| | 1 KB | 1000/1024 = 0.977 | 2.3% | | 1 MB | 1000²/1024² = 0.954 | 4.6% | | 1 GB | 1000³/1024³ = 0.931 | 6.9% | | 1 TB | 1000⁴/1024⁴ = 0.909 | 9.1% | | 1 PB | 1000⁵/1024⁵ = 0.888 | 11.2% | **So a "1 TB" drive (decimal) = 1,000,000,000,000 bytes = 931.32 GiB (binary).** This is not "lost" space — it's the same number of bytes, just relabeled in a system that uses larger base units. **Useful constants:** - 1 GiB ≈ 1.074 GB (decimal-to-binary inflation) - 1 TB ≈ 0.909 TiB (binary-to-decimal deflation at TB) - 1 byte = 8 bits - 1 word = 2 bytes (16 bits) traditionally, or 4 bytes on 32-bit, 8 bytes on 64-bit modern systems

How to use this calculator

Pick the value and starting unit. Most consumer storage discussions use GB and TB.
Select binary if you want OS-style sizes (Windows Explorer, df, ls). Pick decimal if you want vendor-spec sizes.
Read the conversion to all other units in your chosen standard.
For RAM, always use binary (4 GB RAM = 4 GiB = 4,294,967,296 bytes).
For HDD/SSD marketing, use decimal (1 TB drive = 10¹² bytes), then convert to binary to see what your OS will report.
For bandwidth (Mbps, Gbps), bits are decimal by convention (1 Mbps = 1,000,000 bps).

Worked examples

Why my "2 TB" drive shows 1.82 TB

**Scenario:** You buy a 2 TB external SSD. After formatting, Windows shows 1.82 TB free. **Calculation:** 2 TB (decimal) = 2,000,000,000,000 bytes = 1,818.99 GiB ≈ 1.82 TiB. The number of bytes is exactly what was advertised; Windows just uses binary GiB and labels them "GB" (with the leading 1.82 figure). Nothing is missing. **Result:** The drive really is 2 TB by the marketing definition (2 × 10¹²) and 1.82 "GB" by Windows' binary-but-mislabeled definition. Modern Linux and macOS sometimes use the correct "TiB" suffix to disambiguate.

Sizing a photo library

**Scenario:** You shoot RAW on a 24 MP camera. Each RAW file is ~30 MB. You take 200 photos per shoot, 50 shoots per year. How much storage do you need annually? **Calculation:** 30 MB × 200 = 6,000 MB = 6 GB per shoot. 6 GB × 50 = 300 GB/year. Add JPG previews (2 MB each × 10,000 photos = 20 GB). Total: ~320 GB/year. Five years of shoots: 1.6 TB. **Result:** A 2 TB SSD covers about 6 years of shooting. Add a second 2 TB for offsite backup. For a serious photography library, expect storage costs of $100–200/year (including cloud backup) as a hidden line item.

Calculating S3 storage cost

**Scenario:** Your application stores 250 GB of user uploads on AWS S3 Standard at $0.023/GB-month. **Calculation:** 250 GB × $0.023 = $5.75/month = $69/year. With AWS using decimal (1 GB = 10⁹ bytes), you're billed on what you actually store, not the OS-reported figure. **Result:** S3 Standard at $0.023/GB-month makes 250 GB cost about $5.75/month. Tiered to Standard-IA ($0.0125) or Glacier Deep Archive ($0.00099), the same data costs $3.13 or $0.25/month respectively. Egress fees, request fees, and lifecycle transitions are additional and often bigger than storage itself.

When to use this calculator

**Use storage conversion when you need to:**

- **Buy storage**: figure out what an advertised "8 TB NAS" really delivers in your OS (about 7.28 TiB). - **Size cloud storage budgets**: AWS, GCP, Azure all use decimal GB for pricing. The S3 "$0.023/GB-month" is decimal GB. - **Plan backup retention**: incremental backups need careful sizing — daily 50 GB diff × 30 days = 1.5 TB per month per system. - **Estimate database growth**: rows × average row size × growth rate. A million-row table with 1 KB rows is 1 GB; at 10x growth it's 10 GB. - **Convert from bandwidth to storage**: a 100 Mbps stream for one hour is 100 × 3600 / 8 = 45,000 MB ≈ 45 GB of recorded video. - **Translate between RAM and disk**: RAM is always sold in binary GiB labeled "GB" (8 "GB" RAM = 8,589,934,592 bytes). Disk advertised in decimal.

**Real-world units you'll see in 2026:**

- **Phones**: 128 GB, 256 GB, 512 GB, 1 TB (decimal) - **SSDs**: 500 GB, 1 TB, 2 TB, 4 TB (decimal) - **HDDs**: 4 TB, 8 TB, 16 TB, 22 TB (decimal) - **RAM**: 8 GB, 16 GB, 32 GB, 64 GB (binary, despite the "GB" label) - **Cloud blob**: priced per GB-month (decimal); a 1 TB monthly bill = 1,000 GB - **Enterprise NAS**: PB-scale starts to matter; 1 PB ≈ 1024 TB binary or 1000 TB decimal

Common mistakes to avoid

Computing a "missing GB" on a new drive and assuming defect. The bytes are all there; only the unit label changed.
Mixing binary and decimal silently. A "1 TB" backup plan from a cloud vendor (decimal) won't hold your full "1 TB" of local files (binary, 1.099 TB equivalent).
Forgetting filesystem and metadata overhead. NTFS reserves 12.5% for $MFT growth on small drives; ext4 reserves 5% for root by default. Real usable space is less than the formatted capacity.
Assuming "GB" always means the same thing. Storage vendors = decimal. OS file managers = binary. Cloud bills = decimal. Bandwidth specs = decimal bits. Pick the right base each time.
Confusing bits and bytes. A 100 Mbps internet plan moves 12.5 MB/s, not 100 MB/s. The lowercase b vs uppercase B is critical.
Including only logical data when sizing backups. Compression, deduplication, snapshots, and parity (RAID) all change physical storage requirements significantly.
Mistaking the displayed "drive size" for free space. A "256 GB" SSD has ~232 GiB total capacity; after OS and recovery partitions it might offer ~210 GiB free.

Frequently Asked Questions

Sources & further reading

Data Storage Converter

Quickly convert data storage units between bytes, kilobytes, megabytes, gigabytes, terabytes, and petabytes. Supports both binary (1024-based) and decimal (1000-based) conversions.

Inputs

Value

From Unit

Standard

Results

1,024

0.000977

Bytes

1,073,741,824

All Conversions

Unit	Value
Bytes	1,073,741,824
Kilobytes (KB)	1,048,576
Megabytes (MB)	1,024
Gigabytes (GB)	1
Terabytes (TB)	9.7656e-4
Petabytes (PB)	9.5367e-7
Standard	Binary (base 1024)

Last updated: May 28, 2026

About this calculator

Formula

How to use this calculator

Pick the value and starting unit. Most consumer storage discussions use GB and TB.
Select binary if you want OS-style sizes (Windows Explorer, df, ls). Pick decimal if you want vendor-spec sizes.
Read the conversion to all other units in your chosen standard.
For RAM, always use binary (4 GB RAM = 4 GiB = 4,294,967,296 bytes).
For HDD/SSD marketing, use decimal (1 TB drive = 10¹² bytes), then convert to binary to see what your OS will report.
For bandwidth (Mbps, Gbps), bits are decimal by convention (1 Mbps = 1,000,000 bps).

Worked examples

Why my "2 TB" drive shows 1.82 TB

Sizing a photo library

Calculating S3 storage cost

When to use this calculator

**Use storage conversion when you need to:**

**Real-world units you'll see in 2026:**

Common mistakes to avoid

Computing a "missing GB" on a new drive and assuming defect. The bytes are all there; only the unit label changed.
Mixing binary and decimal silently. A "1 TB" backup plan from a cloud vendor (decimal) won't hold your full "1 TB" of local files (binary, 1.099 TB equivalent).
Forgetting filesystem and metadata overhead. NTFS reserves 12.5% for $MFT growth on small drives; ext4 reserves 5% for root by default. Real usable space is less than the formatted capacity.
Assuming "GB" always means the same thing. Storage vendors = decimal. OS file managers = binary. Cloud bills = decimal. Bandwidth specs = decimal bits. Pick the right base each time.
Confusing bits and bytes. A 100 Mbps internet plan moves 12.5 MB/s, not 100 MB/s. The lowercase b vs uppercase B is critical.
Including only logical data when sizing backups. Compression, deduplication, snapshots, and parity (RAID) all change physical storage requirements significantly.
Mistaking the displayed "drive size" for free space. A "256 GB" SSD has ~232 GiB total capacity; after OS and recovery partitions it might offer ~210 GiB free.

About this calculator

Formula

How to use this calculator

Worked examples

Why my "2 TB" drive shows 1.82 TB

Sizing a photo library

Calculating S3 storage cost

When to use this calculator

Common mistakes to avoid

Frequently Asked Questions

What is the difference between binary and decimal storage?

Why does my hard drive show less space than advertised?

How many photos can 1 GB hold?

What does KiB, MiB, GiB mean?

Is RAM measured in binary or decimal?

How big is a petabyte?

How much storage does a typical 1080p movie use?

Sources & further reading

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Inputs

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About this calculator

Formula

How to use this calculator

Worked examples

Why my "2 TB" drive shows 1.82 TB

Sizing a photo library

Calculating S3 storage cost

When to use this calculator

Common mistakes to avoid

Frequently Asked Questions

What is the difference between binary and decimal storage?

Why does my hard drive show less space than advertised?

How many photos can 1 GB hold?

What does KiB, MiB, GiB mean?

Is RAM measured in binary or decimal?

How big is a petabyte?

How much storage does a typical 1080p movie use?

Sources & further reading

Related Calculators

Bandwidth Calculator

Aspect Ratio Calculator

PPI Calculator

URL Encoder / Decoder

AI API Cost Calculator

Password Generator

Inputs

Results

All Conversions