A construction takeoff is the process of measuring a set of plans and specifications to list every quantity a project needs, such as 4,900 SF of drywall, 320 LF of footing, or 42 receptacles. It is the quantity list that a cost estimate is built on. You will also hear it called a quantity takeoff or a material takeoff.
The terms overlap. "Material takeoff" usually means a list of materials by item, like sheets, studs, pipe, and wire. "Quantity takeoff" is the wider term and covers anything you can measure, including work priced by the hour or by the foot, like excavation or painting. Most contractors use them interchangeably.
The four kinds of units a takeoff counts
Every line on a takeoff is one of four unit types. Pick the wrong one and the price will be off, even if the measuring was perfect.
- Count (EA): things you can point at, such as doors, windows, receptacles, light fixtures, plumbing fixtures, and sprinkler heads.
- Linear (LF): things that run, such as footings, baseboard, pipe, conduit, wire, gutters, and curbs.
- Area (SF): surfaces, such as drywall, roofing, flooring, paint, slabs, siding, and stucco.
- Volume (CY): things that fill a space, such as concrete, excavation, backfill, and gravel.
Most trades use more than one. A roofer counts vents, measures ridge and eave in feet, and prices the roof planes by area, usually in squares of 100 SF. A concrete sub counts embeds, measures edge forms in feet, and orders concrete by the cubic yard.
| Trade | Count (EA) | Linear (LF) | Area (SF) | Volume (CY) |
|---|---|---|---|---|
| Concrete | Anchor bolts, embeds | Footings, curbs, edge forms | Slab surface, form contact | Footings, slabs, walls |
| Framing | Hold-downs, hangers | Plates, headers, blocking | Wall and roof sheathing | n/a (lumber is sold by the board foot) |
| Roofing | Vents, skylights | Ridge, hip, eave, flashing | Roof planes | n/a |
| Drywall and paint | Doors and windows to deduct | Corner bead, trim | Walls and ceilings | n/a |
| Electrical | Receptacles, switches, fixtures | Wire, conduit | n/a | n/a |
| Plumbing | Fixtures, valves | Pipe by size | n/a | Trench excavation and backfill |
| Sitework | Inlets, trees | Curb, fence, pipe | Paving, sod | Cut, fill, base rock |
Takeoff vs. estimate
A takeoff answers "how much of each item?" An estimate answers "what will it cost?" The takeoff comes first, and the estimate takes those quantities and adds prices, labor, and markups.
| Aspect | Takeoff | Estimate |
|---|---|---|
| Question it answers | How much of each item? | What will the job cost? |
| Output | Quantities with units | Prices, hours, and totals |
| Built from | Drawings, specs, addenda | The takeoff plus local prices, wages, and markups |
| Typical error | Missed or double-counted items | Wrong rates or missing markups |
A usable takeoff line carries more than a number. It names the item, the unit, the quantity, the sheet the quantity came from, and a note on how it was measured, such as "net of openings" or "includes waste." Without the sheet reference, nobody can check the number, including you six months later when a change order comes in.
Keeping the two apart has a practical benefit. If the quantities are right, you can re-price them next month, or with a different supplier, without measuring again. Our guide on how to estimate a construction project covers what happens after the quantities are done.
Manual, digital, and 3D takeoff
There are three common ways to take quantities off drawings.
- Manual. Printed plans, a scale ruler, and a highlighter. It still works for a small job, but it is slow and hard to check later.
- Digital (2D). You measure on PDF plans on screen. Calibrate the scale, click along each wall or area, and the software adds it up. It is faster, and it leaves a marked-up plan that shows what you counted.
- 3D or model-based. Quantities come from a 3D model of the building. Its best use is as a cross-check, because a model will not agree with a wrong 2D count.
Software measures what you click on, so it does not replace judgment about what to measure. If you are deciding between buying a tool and hiring the work out, read takeoff software vs. an estimating service. For a closer look at the 2D and 3D methods, see 3D takeoff vs. 2D takeoff.
Common takeoff mistakes
Most takeoff errors come from the same handful of habits. These are the ones that cost real money.
Gross vs. net areas
A wall measured as length times height counts the window and door openings as wall. For paint and drywall you usually take the openings out, at least the large ones. For framing you add back the headers and trimmers around them. Decide gross or net for each material before you start.
Areas can also be counted twice. On one custom home in BidMe's own work, the drywall and paint area had been carried at about 7,410 SF when the real figure was about 4,900 SF. Checking the areas room by room caught it.
Waste factors
Material comes in sheets, bundles, and fixed lengths, so you buy more than you install. Keep the net quantity and the waste allowance on separate lines so you can see both.
For example (numbers made up for illustration), if the net wall area is 4,900 SF and you allow 10 percent for waste, you would order for 5,390 SF. A 4 x 8 sheet covers 32 SF, so that is 169 sheets. Real waste depends on the material and the layout, so use your supplier's or manufacturer's guidance and your own history.
Missing addenda
Addenda change the drawings after the set was issued. A takeoff run on the original set can be wrong before you measure anything. Check the addenda log, look at the revision date on every sheet, and confirm the set you are measuring is the latest one.
Lump sums that hide under-counts
A lump sum feels safe because it is quick. It is also where under-counts hide. On a custom estate, site lighting had been carried as a lump sum of about $71,500. Counting every fixture symbol on the lighting sheet turned it into about $194,000 of counted lines.
Shapes that are not clean
Measuring tools treat an outline as one shape. In one case, a drawing outline with a skylight hole in it was read as a single shape, and the roof area came out at about 628 SF instead of the real 727 SF. Always check that each measured shape is one clean outline and that openings are handled on purpose.
How to check a takeoff
A takeoff you have not checked is a guess with a spreadsheet around it. These checks take less time than fixing a bad bid.
- Reconcile areas. Add up floor area room by room and compare it with the total on the plans.
- Compare related quantities. Paint area should track drywall area. A roof's surface area should track its footprint times the slope factor; a 6:12 roof is about 12 percent larger than its footprint.
- Check counts against schedules. Count doors, windows, and fixtures on the plan, then compare with the door schedule, window schedule, and fixture schedule. A mismatch means one of them is wrong.
- Look at the markup. A color-coded plan shows what was measured. Anything left uncolored was not counted.
- Run a ratio. Divide a quantity by the floor area and compare it with a similar past job. A big gap is worth a second look.
- Get a second pair of eyes. Someone who did not do the takeoff will see what the first person stopped noticing.
When to outsource a takeoff
Measuring is skilled work, and it is not billable until you win the job. Consider handing it off when bid volume is higher than your hours, when you are measuring at night after a day on site, when a plan set is in a trade you rarely price, or when you want a second count to compare with yours.
Look for a provider who returns an editable file, shows what was measured, and lists every assumption. Our outsourcing checklist for contractors covers what to ask before you send a set.
Takeoffs at BidMe
BidMe is a construction estimating and material takeoff service for general contractors, subcontractors, builders, and remodelers across the United States. You send plans (PDF is best, and specs and addenda help), get a fixed quote and delivery date, and receive an Excel workbook of quantities by trade, plus color-coded plan markups that show what was measured. In the online Estimate Studio, the estimate opens in 3D next to the 2D plan sheets, so you can compare what was counted with what the drawings show. You can read about the estimation and takeoff service or see pricing: residential estimates start at $200 per project and commercial at $400.
Questions contractors ask
What do I need to send for a takeoff?
Send the full plan set as a PDF, along with the specifications and any addenda. DWG files and plan-room links also work. The specs matter because they say what type and grade of material to price.
How long does a takeoff take?
It depends on the size of the project and the number of trades. A small house plan set can be measured in a day, and a large commercial set takes longer. BidMe delivers most estimates 24 to 48 hours after quote approval.
Can a takeoff be done without the specifications?
The plans show how much, but the specs say what kind. Without them the estimator has to assume materials, which can change the price. Any assumption should be written down so you can confirm or change it.
What is a takeoff list used for after the bid?
Once you win, the quantities become your purchase list, your supplier quote requests, and a baseline for checking change orders. A takeoff that shows how each number was measured makes those jobs easier.
