Key takeaways
- A BOQ exists so every tenderer prices the same scope — its real product is comparability, not the total at the bottom.
- The unit column is where most disputes start. m³, m², m and nos each imply a different measurement rule.
- The lowest total is not always the lowest bid: front-loading and unbalanced rates hide inside a competitive-looking sum.
- Always compare bids line by line, and always check the early items separately from the total.
A bill of quantities is the most-read and least-understood document on a construction project. Clients skip to the last page. Contractors read every line. That asymmetry is where a great deal of money changes hands.
What a BOQ is actually for
A BOQ is an itemised list of every measurable item of work in a project. Quantities are taken off the drawings by a quantity surveyor before tender and issued to every bidder, who fills in only the rate column.
That last detail is the whole point. Because the quantities are fixed and identical for everyone, the bids differ only in rates — so they can be compared line by line rather than as two opaque totals. A tender without a BOQ, where each contractor measures for themselves, produces numbers that cannot be compared at all, because you never find out whether the cheaper bidder is efficient or simply measured less work.
It carries on working after award. The BOQ becomes the basis for interim payment certificates, for valuing variations, and for settling the final account.
Anatomy of a line item
Every line has the same six fields:
| Field | What it does | What to check |
|---|---|---|
| Item code | Reference for correspondence and valuation | That it matches the specification clause |
| Description | Defines the scope of the item | Vague words — "as directed", "as required", "etc." |
| Unit | How the work is measured | That it suits the work (see below) |
| Quantity | Taken off the drawings | Spot-check two or three against the drawing |
| Rate | The only field the bidder fills | Outliers, high and low |
| Amount | Quantity × rate | The arithmetic — errors are common |
The description does more work than it appears to. "RCC M25 in columns including formwork, reinforcement, placing, compacting and curing" and "RCC M25 in columns" are two very different items — in the first, steel and shuttering are inside the rate; in the second they are separate bills and the rate should be far lower. Compare those two rates without reading the descriptions and you will reach the wrong conclusion.
Units, and why they matter
- m³ — concrete, excavation, brickwork. Volume items. Check how deductions are treated.
- m² — plaster, formwork, flooring, painting. Area items. The rule for openings varies by standard.
- m — skirting, pipework, kerbs. Linear items.
- kg or t — reinforcement, structural steel. Weight items, computed from a bar bending schedule.
- nos — doors, fixtures, fittings. Enumerated items.
- LS or item — lump sums with no quantity. These deserve the most scrutiny, because there is nothing to check the rate against.
This is why standard methods of measurement exist. IS 1200 governs in India, NRM2 in the UK, and CESMM for civil engineering works. They settle in advance the questions that would otherwise be argued afterwards: whether openings under 0.5 m² are deducted from plaster, whether excavation includes working space, whether formwork is measured to the contact area. A BOQ that names no method of measurement is an invitation to a claim.
How a rate is built up
Behind every rate is an analysis. Understanding its shape tells you immediately whether a rate is plausible:
Rate = Material + Labour + Plant + Overhead + Profit
Overhead is typically 5–10% of direct cost; profit another 5–15% depending on market and risk.
For 1 m³ of M20 concrete, the material component is the cement, sand and aggregate priced at local rates; labour is mixing, placing, compacting and curing; plant is the mixer and vibrator. When you meet a rate that looks low, work back: if it does not cover materials alone at today's prices, the bidder has either made an error or is planning to make the money elsewhere.
Worked example: two bids, one trap
Two contractors price the same six-item BOQ. Figures are in currency units; substitute your own.
| Item | Qty | Unit | A rate | A amount | B rate | B amount |
|---|---|---|---|---|---|---|
| 1 Excavation | 200 | m³ | 350 | 70,000 | 220 | 44,000 |
| 2 PCC bed | 20 | m³ | 6,500 | 130,000 | 5,200 | 104,000 |
| 3 RCC footings | 45 | m³ | 9,800 | 441,000 | 7,900 | 355,500 |
| 4 RCC superstructure | 120 | m³ | 8,200 | 984,000 | 9,100 | 1,092,000 |
| 5 Brickwork | 180 | m³ | 6,400 | 1,152,000 | 6,900 | 1,242,000 |
| 6 Plaster | 900 | m² | 320 | 288,000 | 340 | 306,000 |
| Total | 3,065,000 | 3,143,500 |
Bidder A is 78,500 cheaper — about 2.5%. On the last page, A wins. Read the lines and a different picture appears:
- Isolate the early items. Items 1–3 are all completed in the first months. A: 70,000 + 130,000 + 441,000 = 641,000. B: 44,000 + 104,000 + 355,500 = 503,500.
- Compare them. A is 27% higher on the early work while being 2.5% cheaper overall. That is the signature of front-loading.
- Work out what it means for cash. By the end of the substructure, A has drawn 137,500 more from you than B for identical work — money you have paid for value you do not yet hold.
- Test the quantity risk. Foundation quantities are the ones most likely to grow, because soil is discovered rather than designed. If excavation and footings both run 25% over, A's overrun costs 128,000 against B's 100,000. A's advantage shrinks to about 50,000.
- Check the exposure if it goes wrong. If the contract is terminated after the substructure, you have overpaid A by 137,500 and must still buy the superstructure at market rates.
None of this makes A the wrong choice — the total is genuinely lower and front-loading is not fraud. But it is a fact about the bid you should know before signing, and it is invisible unless you read the lines.
The traps, in order of how often they bite
- Front-loading. As above. Always price the first three months of items separately.
- Unbalanced rates on uncertain quantities. A bidder who expects a quantity to grow prices that item high and compensates elsewhere. Watch items marked provisional.
- Provisional and prime cost sums. A provisional sum covers work not yet defined; a prime cost sum covers materials from a nominated supplier. Both get adjusted later, so a bid loaded with them is less fixed than its total suggests.
- Vague descriptions. "As directed by the engineer" and "including all incidentals" are where variation claims are born. Push for definition before award, not after.
- Arithmetic errors. Quantity × rate ≠ amount happens more often than anyone expects. Most contracts say the rate governs, so a transposed digit in a rate can be expensive.
- Missing items. The most costly trap of all. Work that appears on the drawing but in no bill will be built, and will be paid for as a variation at a rate you did not compete.
- Rate-only items. Items with no quantity but a rate for future use. They are not in the total, so nobody checks them — until the work is instructed.
Frequently asked questions
What is a BOQ?
An itemised list of every measurable item of work, each with a description, unit, quantity taken from the drawings, rate and amount. It lets every tenderer price identical scope so bids can be compared line by line.
What is front-loading?
Pricing early items above cost and later items below cost while keeping the total competitive. The contractor recovers cash sooner, which improves their working capital and weakens the client's position if the contract ends early.
Provisional sum or prime cost sum — what's the difference?
A provisional sum is an allowance for work not yet defined well enough to measure, adjusted once the scope is settled. A prime cost sum is an allowance for goods or services from a nominated supplier, with the contractor's profit and attendance priced separately.
Why does the method of measurement matter?
Without one, two estimators measuring the same drawing get different quantities. IS 1200, NRM2 and CESMM settle the rules in advance — deductions for openings, working space in excavation, how formwork is measured — so those questions are not argued during the job.