How much storage does Microsoft Flight Simulator X need?

Microsoft Flight Simulator X needs 14 GB of free disk space for the boxed release; FSX: Steam Edition lists 30 GB. These are published minimums, not comfortable long-term allowances. We recommend extra headroom for temporary installation files, saved flights, aircraft, scenery and other add-ons.

These figures apply to FSX, not Microsoft Flight Simulator 2020 or 2024. Those simulators have substantially different requirements, covered in our storage guide for the modern Microsoft Flight Simulator releases.

How much free space should you allocate to FSX?

A sensible target is 25–30 GB free for a mostly stock boxed installation and 40–50 GB for FSX: Steam Edition. These are planning allowances rather than official requirements; they leave room for installation overhead, updates and a modest collection of add-ons.

Do not treat the published figure as the exact installed size. Steam's download size, the final size shown on disk and its free-space requirement are not necessarily identical. Boxed editions can also vary after expansions and optional components are installed. Our complete FSX hardware requirements cover the related processor, memory and graphics specifications.

How much space do FSX add-ons use?

Aircraft usually add comparatively modest amounts, while detailed airports, terrain meshes and photographic scenery can consume tens or hundreds of gigabytes. A heavily modified FSX installation can therefore exceed the base simulator's requirement many times over.

• Aircraft: normally stored under SimObjects, with complex packages also adding gauges, sounds and effects.
• Scenery: often stored under Addon Scenery or in an external library selected by the installer. High-resolution ground imagery is usually the largest consumer.
• Installer archives: downloaded ZIP files and extracted setup folders can leave two extra copies alongside the installed add-on.
• User data: saved flights, flight plans, configuration files and scenery indexes usually remain relatively small, but some are kept on the Windows system drive even when FSX is installed elsewhere.

A mistake we see constantly is allowing enough room for FSX itself but none for the scenery collection planned afterwards. For regular add-on use, choose a drive with at least 100 GB available; allocate considerably more if photographic scenery is the priority.

Can FSX be installed when only 14 or 30 GB is free?

It may fit, but installing with only the stated minimum is poor practice because setup programs need temporary working space and Windows also needs room to operate. A drive that becomes full during extraction can produce an incomplete installation or prevent later add-ons from installing.

Remember that choosing another drive for FSX does not move every associated file there. Windows user folders and shared application-data locations may still use space on the system drive.

Does installing FSX on an SSD change the space needed?

An SSD does not materially reduce FSX's storage requirement, but it can shorten simulator, aircraft and scenery loading times. It should not be purchased on the assumption that it will produce a large frame-rate increase; our FSX SSD-versus-HDD guidance explains when each drive type makes sense.

How can you free or relocate FSX storage?

Remove obsolete installer archives only after confirming that the installed add-on works and that another backup exists. Uninstall unwanted scenery and aircraft through their supplied uninstallers where possible rather than deleting unfamiliar files from the FSX directory.

Do not drag active scenery folders to another disk without updating their registered paths, or FSX may report missing scenery areas at startup. If the present drive is running out of room, follow a safe procedure for moving FSX and its add-ons to another drive.