---
title: "Bill of quantities and abstract of cost"
subject: "Estimating and Costing"
chapter: 2
key: "semester_7/estimating_and_costing:boq-abstract-of-cost"
source: https://www.bctengineer.com/q/semester_7/estimating_and_costing/boq-abstract-of-cost
site: BCT Engineering
---

# Bill of quantities and abstract of cost

Estimating and Costing · Chapter 2: Method of Estimating

- Asked in: 2075 Chaitra, 4 marks; 2076 Chaitra, 2 marks (asked 2 times)
- Video: [What is Bill of Quantity (BOQ)? Explained in Detail with Example.](https://www.youtube.com/watch?v=cKJKSPlMVzA) — Engineering Academy
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/estimating_and_costing/boq-abstract-of-cost
- Whole chapter: https://www.bctengineer.com/md/semester_7/estimating_and_costing/chapter-2

## Question

Explain Bill of quantities and abstract of cost, and enumerate the relationship and differences between the Bill of quantities and the Abstract of estimated cost.

## Short answer

A Bill of Quantities lists items with description, unit, and quantity, used for tendering. The Abstract of Cost multiplies quantities by rates to give amounts and total cost. The BOQ provides quantities; pricing it yields the abstract. The BOQ may omit rates, while the abstract always includes rates, totals, and contingency/VAT.

## Answer

#### Bill of quantities (BOQ)
The BOQ lists all items of work with their description, unit and **quantity** (and, once priced, rate and amount). It is used in tendering and as the basis of the contract and payment.

#### Abstract of cost (AOC)
The abstract of cost is a summary sheet in which the quantity of each item (from the BOQ or quantity sheet) is multiplied by its **rate** to obtain the **amount**; the total of all items, with contingency and taxes, gives the estimated cost of the project.

#### Relationship
- Both are built from the same quantity calculation sheets.
- The BOQ gives quantities; adding rates to the BOQ gives the AOC (a priced BOQ is, in effect, an abstract of cost).
- The totals of both must agree.

#### Differences
| Basis | Bill of quantities | Abstract of cost |
|---|---|---|
| Content | Item, unit, quantity (rate optional) | Item, quantity, rate, amount |
| Purpose | Tender document and contract | Cost estimate for approval |
| Prepared | Before tender, for bidders | In the estimate, by the owner |
| Who prices | Bidder fills in the rates | Estimator uses the analysed rates |
| Shows total cost | Only after pricing | Always, with contingency and tax |

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What does the abstract of cost do?
   A. Lists quantities only
   B. Records actual payments
   C. Lists drawings
   D. Multiplies quantity by rate to get amounts and totals them with contingency and taxes
   Answer: D. It is the cost summary. (Key point: AOC)

2. How are BOQ and AOC related?
   A. Both come from the same quantity sheets; priced BOQ is like an AOC
   B. They are unrelated
   C. AOC is from bidders only
   D. Totals need not agree
   Answer: A. Totals must agree. (Key point: Relationship)

3. In a BOQ, who fills in the rates?
   A. The estimator for approval
   B. The bidder
   C. The engineer's supervisor
   D. No one
   Answer: B. In the AOC the estimator uses analysed rates. (Key point: Who prices)

4. The AOC is mainly for
   A. Tender document for bidders
   B. Final payment
   C. Cost estimate for approval
   D. Material delivery
   Answer: C. BOQ is for tender and contract. (Key point: Purpose)

## Related in Estimating and Costing

- [Bill of quantities and its importance](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Abill-of-quantities) — Estimating and Costing, chapter 2, asked 5×
- [Bill of quantities for RCC T-beam bridge](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Aboq-rcc-t-beam-decking) — Estimating and Costing, chapter 2
- [Estimated cost is never the actual cost](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Aest-cost-never-equal-actual) — Estimating and Costing, chapter 1
- [Compare estimated cost and actual cost](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Acompare-estimated-actual-cost) — Estimating and Costing, chapter 1
- [Estimated cost never actual; data required](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Aest-cost-never-actual-data) — Estimating and Costing, chapter 1
- [Components of complete estimate; abstract cost](https://www.bctengineer.com/question.md?key=semester_7%2Festimating_and_costing%3Acomponents-complete-estimate-abstract) — Estimating and Costing, chapter 2

## Related in other subjects

- [Client, consultant and contractor relationship](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Aclient-consultant-contractor-relation) — Construction Management, chapter 1, asked 6×