Sleepout & Cabin Cost Calculator

This calculator estimates the all-in cost of building a sleepout or cabin in New Zealand, an increasingly popular way to add a bedroom, home office, teenager retreat, guest room or rental space without the cost and disruption of extending the main house. The price depends first on the type and finish. A basic uninsulated cabin used as a sleepout is the cheapest, an insulated and lined sleepout suitable for year-round use costs more per square metre, and a unit with its own bathroom and kitchenette, effectively a minor dwelling, is the most expensive because of the plumbing and fit-out. On top of the building itself, the costs that catch people out are the site works and foundations, connecting power, water and wastewater, and, importantly, building consent and council requirements. In New Zealand, a small detached building under 30 square metres can be exempt from building consent if it meets specific conditions, but anything with plumbing or sleeping in certain configurations usually needs consent, so it pays to check with your council early. You enter the floor area, choose the type, and add figures for site works and foundations, services connection and consent, plus a contingency. The calculator returns the all-in estimate, the building and site components, and the cost per square metre. Use it to compare a cabin against extending the house, to test whether a sleepout stacks up as a rental, or to budget before talking to builders. Costs vary widely by product, site, slope and access, and consent rules differ by council, so treat this as a planning estimate and confirm requirements locally.

Buildings under 30m² may be consent-exempt if they meet the rules; plumbing usually needs consent. Check your council. An estimate; get quotes.