A turnkey or a turnkey project (also spelled turn-key) is a type of project that is constructed so that it could be sold to any buyer as a completed product. This is contrasted with build to order, where the constructor builds an item to the buyer's exact specifications, or when an incomplete product is sold with the assumption that the buyer would complete it.
A turnkey project or contract as described by Duncan Wallace (1984) is:
Turnkey refers to something that is ready for immediate use, generally used in the sale or supply of goods or services. Turnkey is often used to describe a home built on the developer's land with the developer's financing ready for the customer to move in. If a contractor builds a "turnkey home" they frame the structure and finish the interior. Everything is completed down to the cabinets and carpet. "Turnkey" is commonly used in the construction industry, for instance, in which it refers to the bundling of materials and labour by sub-contractors. 'Turnkey' is also commonly used in motorsports to describe a car being sold with drivetrain (engine, transmission, etc.) to contrast with a vehicle sold without one so that other components may be re-used.
Similarly, this term may be used to advertise the sale of an established business, including all the equipment necessary to run it, or by a business-to-business supplier providing complete packages for business start-up. An example would be the creation of a "turnkey hospital" which would be building a complete medical centre with installed medical equipment.
The term turnkey is also often used in the technology industry, most commonly to describe pre-built computer "packages" in which everything needed to perform a certain type of task (e.g. audio editing) is put together by the supplier and sold as a bundle. This often includes a computer with pre-installed software, various types of hardware, and accessories. Such packages are commonly called appliances. A website with a ready-made solutions and some configurations is called a turnkey website.
Turnkey products are synonymous to "off-the-shelf" solutions and not customized.
In real estate, turnkey is defined as delivering a location that is ready for occupation. The turnkey process includes all of the steps involved to open a location including the site selection, negotiations, space planning, construction coordination and complete installation. Turnkey real estate also refers to a type of investment. This process includes the purchase, construction or rehab (of an existing site), the leasing out to tenants, and then the sale of the property to a buyer. The buyer is purchasing an investment property which is producing a stream of income.