Three documents get called the same thing in conversation, and they are not the same thing.
A takeoff is a measurement of a scope. A bill of quantities is a measurement of the whole building, written out so it can be priced. An estimate is a price.
People ask for one and mean another about a third of the time, which costs a week when it happens late. Here is each one in the order they usually arrive.
The takeoff
A takeoff is the act of measuring quantities off a drawing set, and it is also the document that comes out of it. In practice, when somebody asks for a takeoff they usually mean one trade: the concrete, the framing, the mechanical package.
It carries quantities and descriptions. It does not carry rates. The boundary of the package is the most important line in it, because a takeoff is measured on its own, without the rest of the building around it to catch what falls between packages.
Who wants one. Subcontractors and trade services businesses pricing one package on a job somebody else is building. Also builders who want one difficult package measured properly while their own desk carries the rest.
That is the service we call trade-specific takeoffs, and the boundary gets written down before the first quantity.
The bill of quantities
A bill is the whole building written out as a list, trade by trade, with a unit and a quantity against every line. It is structured so an estimator can price straight into it: trade summary, breakups within each trade, returnable pricing schedules, clarification notes against the set.
The difference from a takeoff is not only size. A bill is written to be issued to other people. That changes how it is set out, because it has to be readable by a stranger under time pressure. A takeoff can be terse. A bill cannot.
Who wants one. Builders pricing a tender, developers who want the scope on paper before anyone prices it, and project teams running a competitive tender who need every bidder pricing the same list. The long version is in what a bill of quantities is.
The estimate
An estimate puts a price against the work. Measured quantities first, rates second, so the number is built out of the building rather than fitted to it.
It can land at concept, through design development, or as the tender number itself. What makes it an estimate rather than a guess is that every line can be traced back to something measured, so it survives being questioned.
Who wants one. Builders taking a tender to submission, and clients who need to know what a drawing set is worth before it goes out.
The bill answers how much of everything there is. The estimate answers what it costs. The takeoff answers both, for one trade.
The three in one line
The order they come in
Measure, then price. Always in that direction.
That sounds obvious and it is the single thing that separates a number you can defend from one you cannot. A rate applied to a floor area is fast and it is fitted to the building from the outside. A measured quantity priced line by line is slower and it is built out of the building. When somebody challenges a line in the second one, there is an answer.
On a full estimate the two steps happen inside the same engagement, which is why the boundary between a bill and an estimate blurs in conversation. Underneath, the order never changes.
Which one you need, by who you are
Subcontractor pricing one package. A trade takeoff. You have your own rates. What you want is somebody else's careful measurement of your scope and a clear statement of where your package ends.
Builder pricing a lump sum tender. A bill of quantities, or a full estimate if you want the priced version. If the tenders have stacked up and the desk cannot absorb another one, that is contract estimating, where we run the tender end to end.
Builder on a design and construct bid. A bill with breakups structured for D&C pricing, and a scope gap review in front of it. Under D&C the risk on anything the drawings have not settled sits with you, so what the documents do not say matters as much as what they do.
Developer or client before tender. A bill, so every bidder prices the same scope. If the design is still moving, a cost plan first.
Anyone with almost nothing drawn. An early budget benchmarked against comparable measured work, issued with its basis stated. Not a bill. There is nothing to measure yet.
What each one costs you in time
Not in fees. In your own time, which is the cost people forget to count.
A takeoff hands you quantities and gives you back the evening you would have spent measuring. You still price it, so your rates and your risk judgement stay where they belong.
A bill hands the whole scope to every bidder at once. The time it saves is not yours, it is the tender's: three builders stop asking the same six questions separately, and the answers arrive in one place.
A full estimate takes the most off your desk and puts the most on ours. On a contract estimating engagement that extends to the whole tender, startups through to submission, which is the version builders use when the work has arrived faster than the desk can price it.
Where it goes wrong
Three ways, over and over.
An estimate is asked for when a bill was meant. The client wanted the scope written out. They got a number instead, and now three builders are pricing three different interpretations of the same drawings.
A takeoff is treated as a bill. One package measured properly does not answer for the packages either side of it. The gap between two packages is exactly where a job gets priced twice or not at all.
A budget is treated as an estimate. A benchmarked figure from an early stage gets carried forward into a tender, and by then nobody remembers it was a comparison rather than a measurement. That one is expensive.
What we call them here
Seven services, and the first four are these three documents plus the planning stage in front of them: bill of quantities, full estimates and contract estimating, cost planning and value management, and trade-specific takeoffs.
If you are not sure which one your job wants, send the set and the date. Working that out is a five minute conversation and it is free. Getting it wrong costs a fortnight.