Spec Home: Definition and Use in a House Budget

A spec home is a house a builder constructs before a buyer is under contract, then lists for sale. The builder chooses the plan, finishes and lot, and carries the risk until it sells.

Spec is short for speculative. The builder speculates that the house will sell.

A custom home starts with an owner who has a plan, usually on the owner's lot. Because the choices differ, so do the per-square-foot figures.

NAHB's analysis of Survey of Construction data puts the median price at $153 per square foot for spec homes started in 2024 and $166 for custom homes. The year before, the medians were $150 and $162.

NAHB notes the spec figure excludes record-high improved lot values. On 2,000 sq ft, the medians come to $306,000 and $332,000, a gap of $26,000. These are national medians for single-family detached homes, not a bid for any one house.

Region moves the rate a lot. NAHB reports custom medians from $129 or lower in the East South Central division to above $190 in New England. Treat $153 and $166 as a national starting range, and replace it with a local quote as soon as you have one.

If you buy a finished spec home, you pay a price that includes the builder's lot, profit and overhead. If you build a custom home on land you already own, the lot is yours and the construction figure is closest to what you pay the trades.

Compare like with like: construction cost to construction cost, or price to price. NAHB's 2024 price shares, with construction at 64.4%, help you move between the two. They come from builders selling new homes, so use them as a guide and not a rule.

Start from $153 or $166, enter your floor area in the house construction cost calculator, and read the eight-stage split. Then swap in a local rate when you have one.