What size is a laptop hard drive in MM?

Laptop hard drives come in a variety of sizes, measured in gigabytes (GB) or terabytes (TB). However, the physical dimensions – the actual width, length and height size – of a laptop hard drive are measured in millimeters (MM).

Quick Answer

Most laptop hard drives are 2.5 inches wide, meaning their width is about 64mm. The length varies between 100-150mm depending on the capacity. The height is typically 9.5mm for most drives. So in summary, the average size is:

  • Width: 64mm
  • Length: 100-150mm
  • Height: 9.5mm

Typical Laptop Hard Drive Sizes

There are two common form factors for laptop hard drives:


The most common size for laptop hard drives is 2.5 inches. These drives have a width of about 64mm, a length between 100-150mm, and a height of 9.5mm. Some specific examples include:

  • Western Digital Blue 2.5″ drive – 101.6 x 69.9 x 9.5mm
  • Seagate Barracuda 2.5″ drive – 100.45 x 69.85 x 9.5mm
  • Toshiba MQ01ABD075 – 100.4 x 69.85 x 9.5mm


M.2 drives are smaller, designed to save space in ultra-thin laptops. Their dimensions are:

  • 22mm width
  • 42, 60, or 80mm length
  • 3.5-5mm height

So in summary, M.2 drives have a much smaller footprint, but the standard 2.5″ laptop drive size is about 64mm x 100-150mm x 9.5mm.

The Advantages of a Smaller Drive Size

The development of smaller hard drive sizes has enabled many advances in technology, especially for laptops. Some key advantages include:

  • Allows for thinner and lighter laptop designs
  • Enables better portability
  • Frees up space for other components
  • Allows for SSD technology in compact form factors
  • Uses less power and extends battery life

Without the advent of small, compact storage devices, laptops would be much bulkier and less convenient to use on the go. The decreasing physical size of storage has played a pivotal role in the evolution of laptops over the past decades.

The Connection Between Physical Size and Capacity

Many people assume that a smaller drive automatically means less storage capacity. However, this is not always true:

  • Physical size is not an indication of capacity
  • Higher areal density enables more capacity in smaller sizes
  • SSDs with small form factors can have large capacities
  • Capacity depends on technology, not just physical size

For example, today’s 2.5 inch laptop drives can have capacities up to 5TB, which is huge considering their compact footprint. And M.2 SSDs with dimensions of just 22x80mm can provide 1TB of storage or more. So capacity depends more on the technology and areal density than just the physical dimensions.

Size Comparisons with Other Storage Media

To better understand the size of a laptop hard drive, it helps to compare it against other storage media:

Media Width Length Height
3.5″ desktop HDD 101.6mm 146mm 25.4mm
2.5″ laptop HDD 64mm 100-150mm 9.5mm
M.2 SSD 22mm 42-80mm 3.5-5mm
SD card 24mm 32mm 2.1mm

This helps illustrate the compact size of a 2.5″ laptop hard drive compared to a full size desktop drive. And the even smaller M.2 SSD format used in ultrathin laptops and tablets.

Factors Influencing Drive Size

Some key factors that determine the physical size of a laptop hard drive include:

  • Form factor – The industry standard size specification, usually 2.5″ or M.2.
  • Capacity – Higher capacity means more platters and heads, which increases length.
  • Height – Thinner drives allow thinner laptops, but need smaller internal components.
  • Technology – For example, SSD with no moving parts can be smaller than mechanical HDDs.
  • Connectivity – Interfaces like mSATA, m.2, and mini-SATA are designed for compactness.

Manufacturers have to balance all these factors to develop hard drives that offer maximum capacity in the smallest possible size.

Size and Performance Considerations

While smaller drives enable smaller laptops, it also impacts performance:

  • Smaller platters reduce potential areal density and capacity
  • Less space for heads to move slows data transfer speed
  • Slimmer drive height leaves less room for heat dissipation
  • Compact drives are more susceptible to damage from drops/shocks

On the positive side, flash-based SSDs suffer less performance impact from small size, and continuing technological advancements are improving density and mitigating other drawbacks.

Considering Weight Along with Size

In addition to drive size, weight is an important consideration for laptop drives:

  • HDDs weigh more than SSDs due to moving parts
  • Smaller 2.5″ HDDs weigh ~100g vs 200g for 3.5″ drives
  • M.2 SSDs are lighter still, with typical weights under 30g
  • Lower weight also improves shock resistance when dropped
  • A few hundred grams can make a noticeable difference in laptop weight

So when choosing a laptop drive, be sure to check the weight specifications along with the physical dimensions.


In summary:

  • Laptop hard drives are typically 2.5 inches wide (about 64mm)
  • Length ranges from 100-150mm depending on capacity
  • Most HDD heights are 9.5mm, while SSDs can be even thinner
  • Smaller M.2 sizes are ideal for ultraportables
  • Physical size does not always indicate capacity
  • Density improves over time allowing more capacity in smaller drives
  • Consider weight along with size when selecting a laptop drive

Knowing the standard laptop hard drive sizes in millimeters can help you choose a drive that best fits the performance, capacity, and form factor needs of your device.