"Dollhouse scale" today is conventionally 1:12, which means that 1" in miniature means 12 inches in real life. This scale is also called 1:1 for "one inch to one foot." However, not all houses are 1:12. How do you determine the scale of your house?If the house is 1:12:--A cottage or modern house will have 8" ceilings.--A Victorian mansion will have main-floor ceilings of 10" or so.--Doorways will be at least 6-1/2" high.--An adult doll who fits will typically be 5-1/2" to 6" tall, though 5" action figures look fine in smaller 1:12 houses.--Rooms will rarely be less than 9" deep.--Most "ordinary" dollhouse furniture will fit.If the house is 1:18:--Ceilings will be 6" to 7-1/2" high.--Doors will be 4-7/8" high.--An adult doll who fits will typically be 4" to 4-1/2" tall.--Rooms will usually be 6" deep or more.--"Ordinary" dollhouse furniture seems too big, but half-scale (1:24) furniture is too small. Plastic 1:18 furniture was made in the 1950s-1970s by Renwal, Marx, Plastco, and others; Lundby continues to make wooden 1:18 furniture.Small cottages with 7-1/2" to 8" ceilings can often be furnished either way (1:12 or 1:18), depending on your goals for the house. With a couple exceptions noted below, Greenleaf and Corona Concepts products are nominally 1:12, but some of the smaller cottages can look good with 1:18 furniture.If the house is 1:24 (half-scale):--Ceilings will be about 5" high (ceilings are proportionately higher in this scale to let you get your hands into the rooms).--Doors will be about 3-1/4" high.--Adult dolls will be about 3" tall.--Rooms will usually be 5" to 6" deep.Greenleaf's Fairfield is 1:24. So was the Victorianna (now out of production), a half-scale version of the McKinley.If the house is 1:48 (quarter-scale or train O gauge):--Ceilings will be about 3" high, possibly as low as 2-1/2" inches if the room is shallow.--Doors will be about 1-5/8" high.--Adult dolls will be about 1-1/4" to 1-1/2" high.--Rooms will rarely be more than about 3" deep (rooms run shallow because it's difficult to reach to the back -- 2" or even 1-1/2" is common). The Greenleaf Village works as 1:48, though I've seen one old box that claims it's 3/8-scale, which would be about a bit larger.If the house is 1:144 ("dollhouse for a dollhouse"):--Ceilings should be about 1" tall.--Doors will be more than 1/2" tall, proportioned to work with ceiling height.--Adult dolls will be about 1/2" tall.--Rooms probably won't be more than 1" deep, usually less due to access with low ceilings.These are not all the possible scales; the Universal Scale Converter provides exhausting detail.