BOQ vs BOM vs abstract of cost
Published 16 Aug 2026
Four documents get used interchangeably on Indian construction projects and are not interchangeable at all. Sending the wrong one to a client or a contractor causes real problems — a bill of materials handed over as a BOQ has no rates in it, and an abstract of cost handed over as a BOQ has no measurements behind it.
Here is what each one is.
Bill of quantities (BOQ)
The itemised list of every measurable item of work, each with its unit, quantity, rate and amount.
A BOQ is work-based. Its line items are activities — excavation, PCC, RCC in slabs, brickwork in superstructure, 12mm internal plaster — not products. Each rate is a composite that already contains the material, labour, plant, overhead and profit for that activity.
It is prepared from drawings, following a standard method of measurement, and it is the document a tender is priced against and a running bill is certified against. When a dispute arises about what was agreed, the BOQ is what gets read.
Produced by: the estimator or quantity surveyor, from the drawing set.
Used for: tendering, contract award, interim payment certification,
variation valuation.
Bill of materials (BOM)
The list of physical materials required, in the quantities needed to buy them.
A BOM is product-based. Its line items are things you purchase — 420 bags of OPC 43 cement, 3.2 tonnes of Fe500D in specified diameters, 24,000 bricks, 180 sqm of vitrified tile. There are no labour or overhead components, because you cannot buy labour by the bag.
A BOM is usually derived from a BOQ rather than measured independently. The BOQ says 42 cum of RCC 1:1.5:3; the coefficient says each cum takes 8.06 bags of cement; the BOM says 339 bags.
Produced by: the site engineer or procurement team, usually from the BOQ.
Used for: purchasing, delivery scheduling, stock control, wastage tracking.
Abstract of cost
The summary sheet. Each work section from the BOQ collapsed to a single total, with a grand total at the end.
An abstract has no measurements in it and no individual items. It is one line per section — substructure, superstructure, finishes, joinery, services — and it exists so a client or an approving authority can see the shape of the cost without reading 200 lines.
It is a derivative of the BOQ, never a substitute. If someone asks for an abstract and you have no BOQ behind it, you have a guess with formatting.
Produced by: whoever prepared the BOQ, as its summary page.
Used for: client presentation, budget approval, administrative sanction.
Detailed estimate
The full package: the measurement sheets showing how every quantity was arrived at, the abstract, and often the rate analyses behind non-standard items.
Where a BOQ shows the quantity, a detailed estimate shows the working — the room-by-room takeoff, the deductions, the arithmetic. It is the document that gets scrutinised in government and institutional work, because a scrutinising officer needs to check the measurement, not just accept it.
Produced by: the estimator, as the complete working file.
Used for: technical sanction, audit, scrutiny, defending a figure.
Side by side
| BOQ | BOM | Abstract | Detailed estimate | |
|---|---|---|---|---|
| Line items are | Work activities | Purchasable materials | Work sections | Measurements + activities |
| Contains rates | Yes | Sometimes | Section totals only | Yes |
| Contains labour | Inside each rate | No | Inside section totals | Yes |
| Shows measurement | Quantity only | No | No | Full working |
| Derived from | Drawings | BOQ | BOQ | Drawings |
| Primary user | Contractor, client | Site, procurement | Client, approver | Scrutiny, audit |
The confusions that actually cause problems
Treating a BOM as a BOQ for tendering. A contractor cannot bid against a materials list, because it says nothing about labour, plant or the scope of each activity. This happens most often when someone exports a materials summary from a modelling tool and calls it a bill of quantities.
Treating an abstract as sufficient for a contract. The abstract has no items, so there is nothing to measure against when work is executed or varied. Any contract where the abstract is the annexure will produce a dispute at the first variation.
Assuming the BOM follows automatically from the BOQ. It does, arithmetically, but only if wastage is added. A BOQ quantity is the theoretical finished work; a BOM is what you buy, and steel, tile and brick all generate offcuts and breakage. Ordering to BOQ quantity leaves you short.
Confusing "estimate" with "BOQ" in conversation. A client asking for an estimate usually wants a number. A contractor asking for the BOQ wants the itemised document. Both say "estimate" and mean different things.
Which one you actually need
If you are bidding or awarding work — BOQ.
If you are buying material for a site — BOM.
If you are showing a client the cost — abstract, backed by a BOQ.
If your figure has to survive scrutiny or audit — detailed estimate.
On most residential projects you will end up producing three of the four from the same measurement work, which is why getting the takeoff right matters more than the format.
For how the measurement itself is done, see how to make a BOQ from architectural drawings. For what sits inside each rate, see how to prepare a rate analysis. The layout the finished document takes is set out in the BOQ format for house construction.
Frequently asked questions
What is the difference between BOQ and BOM?
A BOQ lists work activities with composite rates covering material, labour and overhead, and is used for tendering and payment. A BOM lists physical materials in purchasable quantities with no labour component, and is used for procurement. The BOM is usually derived from the BOQ.
Is an abstract of cost the same as a BOQ?
No. The abstract is the summary page of a BOQ — one total per work section, with no individual items or measurements. It is presented to clients and approving authorities, but it cannot be used as a contract document because there is nothing to measure against.
Can you prepare a BOM without a BOQ?
You can, by measuring materials directly, but it is more work and less useful. The normal path is to measure once into a BOQ, then apply material coefficients to each item to derive the BOM.
Which document does a contractor price against in a tender?
The BOQ. The contractor enters a rate against each item and the quantities are supplied by the employer, which is what makes competing bids comparable.
Do I need a detailed estimate for private residential work?
Usually not. Detailed estimates with full measurement sheets are required where a figure must be scrutinised or audited — government, institutional and bank-funded work. For a private client, a BOQ with an abstract is normally sufficient.