What is an electrical takeoff? Definition, steps, errors

In short: An electrical takeoff is the process of counting and measuring every electrical item shown on a set of construction drawings, so you end up with a list of quantities: how many of each device and fixture, and how many feet of each conduit, wire and cable run. An electrical takeoff contains no prices. It is the input to the estimate, which prices those quantities to produce a bid.

Key takeaways

• An electrical takeoff answers “how many and how much”. The estimate answers “what does it cost”.
• Devices, fixtures and gear are counted. Conduit, wire, cable and cable tray are measured by length. Area measurement is occasional in electrical work.
• The plans are not the whole scope. Schedules, the one-line diagram, general notes and the specifications all change what goes on the list.
• Scale is the most consequential setting in an on-screen electrical takeoff. A wrong scale makes every length on that sheet wrong by the same factor.
• The common electrical takeoff errors are wrong scale, missed sheets or addenda, double counting, and re-keying counts into a separate spreadsheet.

What is an electrical takeoff?

An electrical takeoff is a complete list of the quantities of electrical material a job requires, produced by counting and measuring the drawings. The estimator goes through the sheets one at a time, records every item the contractor has to furnish and install, and totals them.

An electrical takeoff is done at bid time, and again, for the affected items, whenever an addendum or change order revises the drawings. Every other number in the bid rests on it.

What gets counted and measured in an electrical takeoff?

An electrical takeoff covers three kinds of quantity: counts, lengths and, less often, areas.

• Counts (each). Receptacles, switches, luminaires, junction boxes, fire alarm and low-voltage devices, disconnects, motor connections, panelboards, transformers and other gear.
• Lengths (feet). Conduit by size and type, branch wire and feeder conductors, MC and other cable, cable tray, surface raceway, and trenching for underground runs.
• Areas (square feet). Used for items sold or budgeted by area, such as electric floor-heating mat, or for early square-foot budget pricing.

Plans show only part of that. The luminaire schedule says what a “Type A” fixture is, along with its voltage and mounting. Panel schedules give breaker sizes and circuit counts. The one-line diagram gives feeder sizes and the service and distribution equipment. The specifications set the rules the drawings don’t repeat: allowed conduit types, minimum conduit size, device grade, and acceptable manufacturers. A careful electrical takeoff reads all of them, because an item that appears only in a schedule or a general note is still in scope.

A floor plan is also a top-down view. It shows the horizontal path of a run but not the vertical conduit from the ceiling down to a device or up into a panel, so estimators add a drop or rise allowance to the measured length.

Takeoff vs estimate vs bill of materials: what is the difference?

A takeoff is quantities, an estimate is quantities with costs and markups, and a bill of materials is the purchasable list of material derived from the takeoff. The three words get used as synonyms, but they are different documents.

	Takeoff	Estimate	Bill of materials (BOM)
Answers	How many, how much	What will it cost, what do we bid	What do we buy
Contains	Quantities by item, often by sheet, area or circuit	Material cost, labor hours, burden, overhead, profit, tax	Item descriptions, part numbers, quantities, units
Prices	None	Yes	Sometimes supplier pricing
Used by	Estimator	Estimator, owner of the business	Purchasing, supplier, project manager
Made	First	From the takeoff	From the takeoff, usually after award

A mistake in the takeoff passes straight into the other two. Pricing and markup cannot correct a missing quantity.

How is an electrical takeoff done?

An electrical takeoff is done by working through the drawings sheet by sheet, marking each item as it is recorded so that nothing is counted twice or missed.

On paper, that meant a printed set, a scale ruler, highlighters and a tally sheet. You highlighted each device as you counted it and each run as you measured it, and a sheet was finished when everything on it was coloured in.

On-screen takeoff does the same job on the PDF. The general method is:

1. Collect the full bid set: drawings, specifications and every addendum.
2. Set the scale on each sheet you will measure.
3. Count devices and fixtures by clicking each symbol, one item type at a time.
4. Trace conduit, cable and feeder runs with a linear tool.
5. Reconcile the counts against the schedules and the one-line diagram.
6. Add what the drawings imply but don’t draw: drops, fittings, supports, and items called out only in notes or specifications.
7. Total the quantities and hand them to the estimate.

Why does drawing scale matter in an electrical takeoff?

Drawing scale matters because every measured length in an electrical takeoff is a distance on the sheet multiplied by the scale. If a sheet drawn at 1/8" = 1'-0" is measured as 1/4" = 1'-0", every run on it reads as half its real length.

Three things cause scale trouble. Sheets in one set use different scales, and site plans typically use an engineering scale such as 1" = 20'. Enlarged plans and details sit on the same sheet as the main plan at a different scale. And a PDF that was reduced or printed to fit no longer matches the scale in its title block, so check one known dimension before trusting any length.

What are the common errors in an electrical takeoff?

The common errors in an electrical takeoff are wrong scale, missed sheets or addenda, double counting, and counts kept in a separate spreadsheet.

• Wrong scale. Every length on the sheet is wrong by the same factor, so nothing looks out of place.
• Missed sheets and addenda. Electrical scope can sit on architectural, mechanical or civil sheets, and an addendum can reissue a sheet you have already taken off.
• Double counting. The same device often appears on an overall plan and on an enlarged plan. Count it on one of them.
• Counts living in a separate spreadsheet. Each number typed from the drawing into a workbook is a chance for a transcription error, and the number in the cell no longer points back to the marks that produced it.

How does TakeOn handle an electrical takeoff?

TakeOn is web-based takeoff and estimating software for electrical contractors, and it keeps the takeoff quantities and the marked-up drawing in the same place. TakeOn runs in a browser on macOS, Windows and Linux, with nothing to install.

In TakeOn each item is placed from a template that carries custom properties such as type, voltage, circuit or mounting. Annotations that share a template but differ in property values fall into separate groups, each with its own running total, so the grouped rollup already has the shape of a bill of materials. See how TakeOn template properties work.

TakeOn sets scale per sheet. You pick a standard architectural or engineering scale or type a custom one, TakeOn reads the scale from the title block when a drawing set is uploaded, and a boundary drawn around a detail gives that region its own scale.

TakeOn totals update as you draw, per group, per page and for the whole plan, and export to Excel or CSV with a column for every property. Two estimators can work the same sheet at once and see each other’s cursors, and an addendum can be uploaded as a new version of the drawings that the takeoff follows forward. For a worked run-through, see the PDF to BOM walkthrough.

Schedule a demo to see an electrical takeoff done in TakeOn on a real plan set.