Sheet 01 · Overview

Plan a small build that actually fits.

Small form factor cases leave millimetres, not centimetres. Pick a case and parts from a community database of more than a thousand cases and thousands of GPUs, coolers, and PSUs — or enter your own numbers — and see every clearance at a glance before anything ships.

Open the fit checker
Drawing title block
ProjectYour next build
Unitsmm
ScaleNot to scale
Rev.A

Sheet 02 · Fit checker

Clearance check

Load a case and parts from the database, or type the limits from a spec sheet yourself. Footnotes about connectors, radiators, or fans often change the numbers, so check them.

Case
mm
mm
mm
mm
mm
mm
mm
Power supplies it takes
Your parts
mm
mm
mm

Only know slots? One expansion slot is 20.32 mm apart, so 2.5 slots ≈ 50.8 mm. Real cards vary.

mm

Case volume

— L

Width × depth × height ÷ 1,000,000. Makers may quote volume with or without feet and handles.

  • GPU length

    Enter both numbers

  • GPU width

    Enter both numbers

  • GPU thickness

    Enter both numbers

  • CPU cooler height

    Enter both numbers

  • Power supply

    Choose both

Sheet 03 · Parts database

Cases and parts

Search the community's SFF PC Master List, then press Use to load a row into the fit checker.

L

Data: SFF PC Master List by u/prayogahs and the r/sffpc community, used with permission. Imported —. Specs can be wrong or out of date — check the maker's page before you buy, and suggest fixes on the sheet.

Sheet 04 · Reference

Form factors

Motherboards
Form factorSize (mm)
Mini-ITX170 × 170
Mini-DTX203 × 170
Micro-ATXup to 244 × 244
Power supplies (nominal W × H × D)
Form factorSize (mm)
SFX125 × 63.5 × 100
SFX-L125 × 63.5 × 130
Flex ATX81.5 × 40.5 × 150 depth varies
ATX150 × 86 × 140 depth varies

Expansion slots are spaced 20.32 mm (0.8 in) apart. Dimensions are nominal — always confirm with the manufacturer's drawings.

Sheet 05 · Notes

Before you buy

  1. Power connectors stick out

    GPU power plugs and their cables need room to bend. A card that "fits" by length can still hit a side panel.

  2. Count the fan

    Cooler height limits include the fan. Swapping to a slim fan can change the result.

  3. Check RAM clearance

    Low-profile coolers can overhang memory slots. Tall heat spreaders may not fit underneath.

  4. Match the riser

    In sandwich layouts the GPU connects through a riser cable. Match its PCIe generation to your board and card; if you see errors, some boards let you set a lower generation.

  5. Plan the airflow

    Decide where cool air enters and hot air leaves before choosing fans. In small cases, every component shares the same air.

  6. Mind the cables

    Shorter or modular power-supply cables reduce clutter. Also check where front-panel and USB-C headers sit on your board.