Define C

A flexible platform for a powerful ATX build that wastes no space

  • Define Series sound dampening with ModuVent™ technology
  • Optimized for high airflow and silent computing
  • Side and front panels are lined with industrial-grade sound dampening material


View specifications

The perfect balance of capacity and efficiency

Smaller than the usual ATX case, the Define C and its optimized interior provides the perfect base for users of all kinds. The open air design offers unobstructed airflow across your core components with high performance and silent computing in mind at every step.

Key features

  • Define Series sound dampening with ModuVent™ technology for silent operation in a compact micro ATX form factor

  • Optimized for high airflow and silent computing

  • Side and front panels are lined with industrial-grade sound dampening material

  • Flexible storage options with room for up to five drives

  • Comes with two preinstalled Fractal Design Dynamic X2 GP-12 120 mm fans optimized to deliver maximum airflow while still maintaining a low noise level

  • Open air designed interior creates an unobstructed airflow path from the front intake to the rear exhaust

Hide the mess

Power supply shroud conceals drive cage and excess cabling for an even quieter and cleaner looking interior free of airflow obstructions 

Optional filter included

Includes optional top filter to prevent dust buildup when ModuVent is removed for additional fan slots

Easy-to-clean filters

Easy-to-clean high airflow nylon filters on the front and base with full PSU coverage and front access for convenience


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“The new design is tidy and, as our results show, efficient from an air-cooling perspective. It's a good choice for a new micro-ATX build”
“Sound-dampening materials, a top ModuVent, versatile radiator compatibility, a hidden PSU compartment and a design free of unnecessary frills. Define C ticks all those boxes and serves as a smaller, more affordable alternative to the trendsetting Define R5.”
“All told, Fractal's latest delivers every bit of the clean styling, quiet manners, modular touches, and solid performance we've come to expect from the company's other cases”
The Tech Report Read the full review


  • 3.5" or 2.5" drive capacity
  • Dedicated 2.5" drive capacity
    3 (maximum 2.5" drive thickness is 10 mm)
  • Expansion slots
  • Front ports
    2x USB 3.0, Audio in/out, Power button with LED, HDD activity LED, Reset button
  • Total fan mounts
  • Front fan
    3x 120 or 2x 140 mm (1 x Dynamic X2 GP-12 included)
  • Top fan
    2x 120/140 mm
  • Rear fan
    1x 120 mm (1 x Dynamic X2 GP-12 included)
  • Bottom fan
    1x 120 mm
  • Dust filters
    Bottom fan + PSU, Front fans, Top fans (optional)
  • Cable routing grommets
  • Fixed Velcro straps
  • Captive thumbscrews
    Right side panel, SSD brackets
  • Left side panel
    Industrial sound-dampened steel
  • Right side panel
    Industrial sound-dampened steel


  • Power supply type
  • Motherboard compatibility
    ATX, mATX, ITX
  • Front radiator
    120/240/360 mm or 140/280 mm (max 144 mm width)
  • Top radiator
    120/240 mm (max 40 mm motherboard component height)
  • Rear radiator
    120 mm (max 125 mm width)
  • PSU max length
    175 mm
  • GPU max length
    Max 315 mm with front fan mounted
  • CPU cooler max height
    172 mm
  • Cable routing space
    15-35 mm


  • Case dimensions (LxWxH)
    399 x 210 x 440 mm
  • Case dimensions - with feet/protrusions/screws
    413 x 210 x 453 mm
  • Net weight
    7.4 kg
  • Package dimensions (LxWxH)
    542 x 305 x 493 mm
  • Package weight
    7.81 kg
  • Volume
    36.9 liters


  • Warranty
    2 Years
  • Package contents
    Define C computer case; User manual; Accessory box; Optional top filter
  • EAN
  • UPC
  • Product code