One boundary. Every form.

FORMGIVING is the tool this domain is named for, and it works at the earliest stage of the job — while the shape is still being decided. Draw a site boundary on satellite imagery, choose one of six massing types (podium, vertical, cascading, helix, courtyard, signature) or let Generate compose one from the parcel itself, set a floor count and a floor height, and the volume stands up in three dimensions on the real map, against the real neighbours, at the real orientation. It is the same kind of scene turning behind the headline at the top of this page.

Generate is the seventh type and the one with no fixed shape. It composes a study from a vocabulary of fifteen moves: set back, shift, twist, notch, court, terrace, taper, cantilever, slot, stagger, bar, wing, bridge, and a step-down toward lower neighbours. Every dimension is taken from the parcel’s own edges and its neighbours’ heights, so the same seed on a different site is a different building. A board of six is drawn at once for comparison; the seed travels in the link, so a result comes back exactly. No model runs and nothing is sent anywhere: it is geometry in the page.

Around the massing: pin seeds and compare their figures side by side: floor area, ground covered, envelope used, the street wall; switch the sun on for a date and a clock time and see the proposal’s shadow, and the neighbours’ shadow on the parcel, with the hours of daylight the site keeps; export the study as GeoJSON, OBJ or glTF for Rhino, SketchUp, Blender or a web viewer; and read it all in English or 한국어. Every one of those is arithmetic in the browser, checked by tests that drive the page.

The figures come off the polygon you drew rather than off an assumption. Area and edge lengths are measured on the WGS84 ellipsoid, not on a sphere, which is worth saying because the usual browser shortcut is off by up to eight tenths of a percent and the error leans one way with latitude. The bearing is reported as an axis, so drawing the same edge in the opposite direction cannot flip it by a hundred and eighty degrees. The aspect ratio is the long side over the short side of the smallest rectangle that encloses the site at any rotation, which is what the phrase means; an earlier version reported slenderness and called it an aspect ratio. Height is floors times the floor height you set, and that height is now printed instead of being assumed silently at three and a half metres.

It runs entirely in your browser. There is no account, no signup and no server: the geometry that used to need a Python backend was ported into the page, so the whole thing is static files. The outline you draw and every number it produces stay on your machine. Map imagery comes from Esri, building outlines from OpenFreeMap, and an address you type into the search box goes to OpenStreetMap’s geocoder. Those three, and nothing else. The tool carries no advertising.

Conceptual massing in any case. Not intended for construction, regulatory or legal use.

Open the massing tool

Sixty-six of them right now, under the name DATUM. Concrete, rebar, stairs, framing, insulation, roofing, tile, drywall, paint, excavation, retaining walls, and the rest of the arithmetic that stands between a sketch and an order.

Free, no account, no email. They open in a browser, including the one in your pocket, and nothing you type into a calculator leaves it.

Open the calculators

Claiming that everything is sourced is easy, so here is the ledger.

• Stair geometry. IBC 1011.5 and IRC R311.7, cited by section and checked separately, because the two do not set the same limits and a stair can satisfy one while failing the other.
• Rebar spacing. The ACI 318 maximum, applied as a check against the layout you asked for rather than offered as a suggestion.
• Framed wall performance. The parallel path method with a framing factor, which is why the figure it returns is lower than the one printed on the insulation.
• Post embedment. The one-third rule, plus a frost depth warning, because a depth that holds in one climate heaves in another.
• Bag yields. The manufacturer's technical data sheet, by number, not an average of what other calculators assume.
• Unit conversion. Exact legal definitions. One square foot is 0.09290304 m². One pyeong is 400/121 m². Both are exact, and both are usually rounded away.
• Aggregate tonnage. A stated density, shown as the assumption it is rather than folded silently into the result, since that assumption is what decides whether the delivery arrives short.
• Roof area. The pitch multiplier from the geometry, which is why the roof is always larger than the footprint under it.

Codes get amended and manufacturers change their products. A calculator quietly running on a superseded edition is worse than no calculator at all, so the constants get re-checked against their sources instead of being set once and forgotten. Naming the source on the page does the other half of that job: when your jurisdiction amends something, you can see exactly which line to stop trusting.

This is the part the genre leaves out, and it is most of the reason these exist.

A stair can be perfect on paper and fail inspection. Divide a total rise into a riser count that produces a legal riser and you can still end up with a tread that is short, a headroom that is gone, or a dimension that clears one code and not the other. The number was never the hard part.

The hole will not fill itself. Soil comes out of the ground larger than the space it occupied and goes back smaller once compacted. Order backfill by the size of the excavation and you are short. Haul by the same figure and you pay for trips you did not need. Bank, loose and compacted are three different numbers for the same dirt.

Gravel ordered by volume arrives short. It is sold by weight. Weight follows a density that varies with the material, the gradation and how wet it was when it was loaded. A tonnage calculated from an unstated density is a guess wearing a decimal point.

Walls fail from water, not from a miscount. A retaining wall with the right block count and no drainage stone behind it is a wall on a schedule. Height is the other one: past a certain point the job needs an engineer and a permit rather than a calculator, and the page says where that line falls.

Lumber is billed on the nominal size and built with the actual one. A 2x10 is 1.5 by 9.25 inches in the wall and a 2x10 on the invoice. Board feet follow the nominal figure, framing follows the real one, and both belong on screen at once.

A wall does not deliver the number printed on the insulation. Studs bridge the cavity and conduct around it, so the assembly performs below its nominal rating, and the gap grows wider the better the insulation gets. Specifying to the nominal figure is how a wall misses an energy target on paper that it was never going to hit in the field.

A practising architect in New York. One person, not a team, not a company, not an agency.

Every tool here started as a question I could not get a trustworthy answer to during real work. That is the whole editorial policy, and it decides what gets built, what gets re-checked, and what gets refused.

You will find no user count on this page, no logo wall, no testimonial from someone who does not exist. That is deliberate. The verifiable thing about a calculator is not how many people have used it. It is whether the constant it used is the one printed in the code book. Every constant here names its source, so you can check the thing itself instead of the popularity of the thing.

How the numbers are checked

These are design aids. Not compliance certification, not professional advice, and not a substitute for the person who signs and seals the drawings.

Codes are adopted and amended state by state and town by town. Before you rely on anything here, confirm the edition in force and any local amendment with the authority having jurisdiction. Manufacturer figures move with the product, so check the bag, the box or the data sheet you have in your hand rather than the one that was current when a page was written. Anything that carries real consequence goes to the licensed professional responsible for the work.

The calculators keep what you type inside your browser. What the rest of this domain does with a visit is set out on the privacy page.

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