Architecture & Design Calculators — United States
The arithmetic of buildings — geometry, light, sound, heat, safety and cost. The formulas are universal; the code limits you compare against are inputs, because they differ by jurisdiction.
Geometry & area
Net Lettable Area Calculator
Net lettable area from gross floor area — the cores, plant, lobbies and walls that come out — and the efficiency ratio that tells you whether a floor plate is any good.
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Ceiling Height Calculator
A room's volume and air per occupant from its dimensions, against the minimum ceiling height your code requires and the height that makes a room feel right for its size.
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Span to Depth Ratio Calculator
The structural depth a span needs, from the span-to-depth ratios each system typically achieves — a sketch-design check before an engineer sizes anything.
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Façade Panel Count Calculator
How many cladding panels an elevation needs from its dimensions and the panel module — with the part-panels at the edges, the waste they create, and what a different module would save.
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Modular Grid Calculator
How a plan dimension breaks into a planning module — how many modules fit, what is left over, and the dimension that would fit exactly — for setting out on a grid.
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Workspace Density Calculator
Floor area per desk and per person for an office — against the benchmarks that separate dense from generous — and how many people the space could hold at a target density with a desk-sharing ratio.
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Site Coverage Calculator
Building footprint as a share of the site — the site coverage control in most planning schemes — with the impervious share, the footprint a limit allows, and the open space that is left.
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Façade Proportion Calculator
The proportion of a façade or an opening — width to height — against the ratios architects have used for centuries, and the dimension that would bring it to the nearest one.
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Light, sound & heat
Window to Floor Ratio Calculator
Glazing area as a share of floor area — the first check on whether a room gets enough daylight, and the first warning that it will overheat.
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Reverberation Time Calculator
The reverberation time of a room from its volume and the absorption of its surfaces — Sabine's equation — against the target for its use, and how much absorption would fix it.
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Building Energy Intensity Calculator
A building's energy use intensity — kilowatt-hours per square meter per year — from its bills and floor area, against typical bands, and what a reduction target means in energy and money.
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Solar Shading Overhang Calculator
The overhang depth that shades a window at the summer solstice while letting the winter sun in — the geometry of passive solar design, from latitude and window height alone.
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Operative Temperature Calculator
The operative temperature a room feels like — the blend of air temperature and the radiant temperature of its surfaces — and whether it sits in the comfort band.
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Daylight Factor Calculator
The average daylight factor of a room — the share of outdoor light that reaches the inside — from glazing area, glass transmittance, the room's surfaces and how much sky the window sees.
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Air Changes Per Hour Calculator
Air changes per hour from a ventilation rate and a room volume — or the airflow a room needs for a target rate — against the rates typical for each kind of space.
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Safety & circulation
Occupant Load Calculator
The occupant load of a floor from its area and use — the number every fire and egress calculation starts from — and the total exit width and number of exits it needs.
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Lift Count Calculator
How many lifts a building needs — from its population, floors and the peak five-minute handling capacity a lift bank must deliver — and the interval between cars that results.
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Travel Distance to Exit Calculator
The travel distance from the farthest point on a floor to an exit — along the actual path, not the straight line — against the limit your code sets, and the second exit that a long distance forces.
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Cost & practice
Embodied Carbon Calculator
The upfront embodied carbon of a building from its material quantities and carbon factors — per square meter against the benchmarks the profession now uses, and which material dominates.
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Cost Per Square Meter Calculator
Construction cost from floor area and a rate per square meter — or the rate a budget implies — with the on-costs that turn a build rate into a project cost.
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Prefab Module Count Calculator
How many volumetric modules a building needs, how many truck loads that is, and how many days of craneage — the logistics that decide whether modular construction works for a project.
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Office Fit-Out Cost Calculator
An office fit-out budget from floor area and the grade of fit-out — basic, mid or premium — with furniture, services, fees and contingency added the way a real budget adds them.
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Building Lifecycle Cost Calculator
The whole-life cost of a building or an option — capital plus discounted operating, maintenance and replacement costs over its life — so a cheaper build can be compared honestly with a cheaper-to-run one.
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Drawing Scale Calculator
Convert between real dimensions and drawn dimensions at any scale — and find the scale that fits a building on a sheet, which is the question that actually comes up.
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Design Fee Calculator
A design fee from the construction cost and a percentage that falls as the project grows and rises with complexity — with the fee split across the stages the way practices actually invoice it.
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About these calculators
These are design-stage calculations from the standard relationships — Sabine's equation, the daylight-factor rule, occupant load factors, the thin-lens of building physics. They size and check a scheme; they do not certify one. Every code threshold is an input with a common default so you can set the one that applies to you.