Schedule of Works vs Bill of Quantities
The short answer
Both are documents a contractor prices from. A schedule of works describes the work in words, section by section, and leaves the contractor to measure it and price each item as a lump sum. A bill of quantities states the quantities — measured for you, normally by a quantity surveyor to a standard method of measurement — and the contractor prices a rate against each measured item.
The practical difference is who does the measuring, and therefore who carries the risk if the measurement turns out to be wrong. Smaller and refurbishment jobs normally use a schedule of works, because producing a full measured bill costs more than it saves.
What a schedule of works is
A written list of the work to be carried out, broken into sections that follow the order the job gets built — preparation, demolition, groundworks, structure, roof, finishes and so on. Each item describes a piece of work in enough detail for somebody to put a price against it, without stating how much of it there is.
The contractor reads the item, works out the quantities from the drawings themselves, and returns a lump sum. That is the important consequence: the measuring is done once by each tenderer rather than once by the employer's surveyor.
A good one also states what has been assumed, what is excluded, what is carried as a provisional allowance and what still needs confirming. On a job where the drawings are not fully resolved — which is most refurbishment work — that list is doing as much work as the items themselves.
What a bill of quantities is
A measured document. Each item states a quantity and a unit — cubic metres of excavation, square metres of blockwork, linear metres of skirting — and the contractor enters a rate against it. Rate multiplied by quantity gives the item total, and the totals give the tender sum.
The measurement is normally carried out to a standard method, so that every contractor is pricing the same basis and knows what is deemed to be included in a rate rather than measured separately. In the UK that is generally the RICS New Rules of Measurement (NRM2), which replaced SMM7.
Producing one is a substantial exercise and normally needs a fully developed design to measure from. That is the main reason it is not used on smaller jobs: there is nothing wrong with a bill on a domestic extension except that it will cost more to produce than it saves.
Side by side
The differences that actually matter
| Schedule of works | Bill of quantities | |
|---|---|---|
| What it is | A written description of the work, section by section | A measured list of items with quantities against each |
| Quantities | None. The contractor measures the job themselves | Measured and stated, normally to a standard method of measurement |
| How it is priced | A lump sum against each item, or against the whole | A rate against each measured item, extended to a total |
| Who normally prepares it | An architect, a surveyor, or the contractor | A quantity surveyor |
| Typical use | Domestic work, refurbishment, alterations, smaller commercial jobs | Larger, fully designed projects let by formal tender |
| Who carries a measurement error | The contractor — they did the measuring | Normally the employer, where the quantities form part of the contract |
| Comparing tenders | Harder — every contractor has measured it their own way | Easier — everyone prices the same quantities |
The part people miss: who owns the quantities
This is the difference with money attached, and it is worth understanding before choosing between them.
Where a bill of quantities forms part of the contract documents, the quantities are the employer's statement of the job. If a quantity is wrong, the correction is normally dealt with as a change to the contract rather than absorbed by the contractor — so the risk of a measurement error generally sits with the employer.
With a schedule of works, each contractor has measured the job themselves to arrive at their lump sum. If they have under-measured, that is normally their problem. The employer buys more certainty about the price and less about whether every tenderer priced the same thing.
Neither is better in the abstract. A bill costs money to produce and moves quantity risk to the employer; a schedule is cheaper to produce and leaves that risk with the contractor, who will price for it. Standard contract forms exist for both arrangements, and which one applies is a question for whoever is advising on the contract rather than something to infer from the document itself.
Choosing
Which does your project need?
A schedule of works usually fits when
- The job is domestic, refurbishment, alteration or fit-out
- The design is developed enough to describe but not fully resolved
- The cost of measuring the whole job would be out of proportion to the job
- You are inviting a small number of contractors you already know
- Much of the work is making good, and the extent only becomes clear on opening up
A bill of quantities usually fits when
- The project is large enough to justify the cost of measurement
- The design is complete enough to measure accurately
- You are tendering competitively and want prices that are strictly comparable
- You want a priced document to value interim payments and variations against
- A quantity surveyor is already appointed
In practice the two are not mutually exclusive. Plenty of jobs are let on a schedule of works with a handful of measured items for the work that genuinely needs it, and plenty of bills carry provisional sums for the parts nobody could measure yet.
Related questions
- What is the difference between a schedule of works and a bill of quantities?
- A schedule of works describes the work in words, section by section, and the contractor works out the quantities for themselves and prices each item as a lump sum. A bill of quantities states the quantities, measured for you, and the contractor prices a rate against each measured item. The practical difference is who does the measuring and therefore who carries the risk if the measurement is wrong.
- Is a schedule of works the same as a scope of works?
- They are used interchangeably in practice, and on most jobs nobody will pull you up on it. If there is a distinction, a scope of works tends to describe the extent of what is included at a higher level, while a schedule of works breaks the same thing into individual priceable items in a sequence. What matters is that the document is detailed enough to price.
- Is a schedule of works the same as a specification?
- No. A specification says what standard the work must meet — materials, products, workmanship, tolerances. A schedule of works says what work is to be done and where. They are complementary: the schedule item says "form new opening in load-bearing wall and install steel beam to structural engineer's design", and the specification says what the steel, the padstones and the making good must comply with. Most jobs need both, and the schedule usually refers to the specification rather than repeating it.
- Is a schedule of works the same as a programme?
- No, and this catches people out because of the word "schedule". A schedule of works contains no dates and no durations. A programme is the time plan — when each activity starts and finishes. If somebody asks for a schedule of works and receives a Gantt chart, one of you has misunderstood the other.
- Is a schedule of rates the same as a bill of quantities?
- No. A schedule of rates lists prices for units of work without stating how much of each there will be — useful where the extent is genuinely unknown at the outset, such as reactive maintenance or unpredictable repair work. A bill of quantities states the quantities. A schedule of rates is a way of agreeing prices in advance; a bill of quantities is a way of pricing a defined job.
- How is a bill of quantities measured?
- Normally in accordance with a standard method of measurement, so that every contractor is measuring and pricing on the same basis. In the UK that is generally the RICS New Rules of Measurement, NRM2, which replaced SMM7. The method matters because it defines what is deemed to be included in an item and what has to be measured separately — which is exactly what a contractor needs to know before pricing a rate.
- Which one do I need for a domestic extension?
- In most cases a schedule of works. A full measured bill is a considerable piece of work and the cost of producing it rarely stacks up against a domestic job — but a good schedule of works still gets you comparable tenders, provided every contractor is pricing the same described items with the same exclusions stated.
- Can I get comparable prices from a schedule of works?
- Yes, if the document is written properly. The risk is that each contractor measures the job slightly differently and makes different assumptions about what is included, so the prices are not strictly like for like. That is why the exclusions, assumptions and provisional items matter as much as the work items — stating them explicitly is what makes the tenders comparable.
- Who should prepare a schedule of works?
- Whoever knows the job and can describe it in terms a contractor can price. On a domestic project that is often the architect, sometimes a surveyor, and sometimes the contractor themselves — though a contractor writing the document they will then price against is worth being aware of. The document should say who wrote it and what information it was based on.
- What should a schedule of works actually contain?
- Work items in the order the job gets built, each one stating what the work is, where it is, and enough of its extent to price. Alongside them it should carry the things the drawings did not settle: assumptions made, work excluded, provisional allowances, PC sums, and anything needing confirmation. A schedule with no such list has usually not been checked rather than having nothing to declare.
Where our own tool fits
Scopa writes schedules of works, not bills of quantities
Since this is our site, it is only fair to say so plainly. Scopa reads a PDF drawing set and writes a first-draft schedule of works, together with the assumptions, exclusions, provisional items and confirmations described above. It does not measure anything and it does not price anything, so it does not produce a bill of quantities and is not a substitute for a quantity surveyor.
If a bill is what your project needs, this guide has done its job by telling you that.
This guide describes general UK practice and is not professional or contractual advice. How risk is actually allocated on your project depends on the contract you sign and the documents attached to it — take advice from whoever is administering it.