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Cross-market term

First floor / ground floor

How the storeys of a building are numbered from the entrance level upward — a convention that differs by market, so the same label denotes different levels.
  • 4Markets
  • NoSame thing everywhere
  • 1Calculators

What it is called, by market

One concept, four markets. Where a name means something else locally, the card says so rather than leaving you to find out on site.

  • United Statesyours

    Same word, different thing

    first floor

    also ground floor, level 1

    The first floor IS the entrance level. The storey above it is the second floor.

  • Canada

    Same word, different thing

    first floor

    also ground floor, main floor

    As the United States, though "ground floor" and "main floor" are both common for the entrance level.

  • United Kingdom

    Same word, different thing

    ground floor

    also level 0

    The entrance level is the GROUND floor; the first floor is one storey above it.

  • Australia

    Same word, different thing

    ground floor

    also level 0

    As the UK, the entrance level is the ground floor and the first floor is one storey above it — so an Australian first floor is an American second floor.

Calculators for this

Each works in either measurement system, and the terminology on the page follows whichever market you have selected.

Stair Rise & Run Calculator →

Frequently asked questions

Which level is the first floor?
It depends on the market, and the two conventions are offset by exactly one storey. In the United States and Canada the first floor is the entrance level, so first and ground mean the same thing and the storey above is the second. In Britain, Australia and most of Europe the entrance level is the ground floor and the first floor is one above it, so the British first floor is the American second. The offset persists all the way up, which means a document that names levels rather than numbering them from a datum can misdirect a delivery, an inspection or an installation by one storey without anything in it looking wrong.
How do you write a level unambiguously?
By referring to a datum rather than a name. Drawings resolve this with a level in metres or feet relative to a stated datum — a site datum, a benchmark, or finished floor level of a named storey — which is unambiguous in any market because it is a measurement rather than a label. Where names are unavoidable, spelling out "the entrance level" or "one storey above entrance level" removes the ambiguity that "first floor" carries. Building information models and level schedules usually carry both, a name and a datum, and it is worth checking that a document's names and its datums agree before working from either.
Does the mezzanine or basement numbering differ too?
Yes, and below ground there is less agreement than above it. Basements are numbered downward in both conventions, but the labels vary — B1, LG, lower ground, level -1 — and a building on a slope can legitimately have two entrance levels, each called ground by the people who use that entrance. Mezzanines are the other ragged case: an intermediate level between two storeys may be numbered as its own level, given a letter, or not numbered at all, which shifts everything above it if the numbering is sequential. Lift call buttons are a notorious instance, since they follow the building's own scheme rather than any market convention.