Construction takeoff on a Mac

A takeoff, not a coloured drawing

Marking up is drawing a conversation onto the sheet; takeoff is turning the sheet into quantities the estimate can price. The output is a schedule: rows of labels, values, units and groups, summing to totals somebody will compare against a rate build-up. The drawing is evidence, not the deliverable — which is why each number has to carry its sheet, its label and the convention it was measured to.

Set the set up once

Name the sheets as the drawing register names them, then calibrate sheet by sheet. A set mixes scales: the site plan is 1:500, floor plans 1:100, sections 1:50, details 1:20, sometimes a 1:5 junction. At 1:100 one millimetre on paper is 100 mm of building, at 1:500 it is 500 mm — half a metre per millimetre — so carrying one sheet's scale onto another is the single easiest way to be wrong by a factor of five.

Where the PDF was plotted reduced, the title-block scale is a lie on paper. Calibrate against a dimension the drawing states — a gridline run, a stated overall width — then check it by measuring a second stated dimension elsewhere and comparing. Agreement within a millimetre or two is the target; a difference means the sheet is not to scale and the known-dimension route is the only reliable one.

Wall lengths

A 10 m partition run on a 1:100 sheet is 100 mm long on the page, and the app draws the dimension label as 10.00 m because the calibration says so. Measure to gridline intersections or to internal faces — pick one and keep it — and label each measurement with the level and the wall type. Group the run as “Level 1 — partitions” and the subtotal appears without a spreadsheet, ready to compare with the pricing document.

Doors and openings deduct or do not, depending on the measure; for a stud-partition takeoff the usual answer is a running length to internal faces with openings noted separately, so the reviewer can see both the gross run and the exceptions.

Room-by-room areas

Close a polygon around each room and the area tool applies the squared scale factor. At 1:100, a room measuring 83 mm by 62 mm on paper is 8.30 m by 6.20 m on site, so 51.46 m². Label each room the way the schedule needs it — room number, name, floor finish code — and group by level, by trade or by finish. Keep a note in the label where a number is an exception: “excludes risers”, “to internal face”, “gross including ducts”. A number with its convention attached survives a QS review; a bare area invites a fifty-email argument.

Counts

Doors, windows, sanitaryware, sockets, columns, manholes — a click each, coded in the label so the group total lands beside the corresponding schedule. Counts are where a takeoff earns its fee quickly: a door schedule extracted from the drawing and checked against the printed schedule takes minutes, and the CSV gives the estimator a number to reconcile rather than to transcribe.

Revisions

Drawings get reissued. Cloud what changed on the new revision, check the calibration, and remeasure the affected rooms and runs rather than the whole set; the measurement list keeps the labels, so the new CSV sits beside the old one and the differences are the change. Re-export the flattened PDF and the CSV together, and the transmittal tells the whole story: what changed, and what it cost.

Rules that keep the numbers defensible

One calibration per sheet. One convention per group, written into the labels. Sheet names that match the drawing register. A marked-up PDF exported alongside every CSV so each row can be traced to a line. Quoting the unit — m, m², nr — in every schedule row so totals cannot be summed across incompatible units. None of this is software; it is the method the software has to support.

What it does not do

It does not OCR a scanned drawing into geometry, it does not count symbols automatically by AI, and it does not import Revu .bpx tool sets. There is no Windows build. Those absences are deliberate: the product is one Mac-first browser tool for marking up and measuring drawings, and it will not guess at a quantity a person should click.