How to analyse contractor tenders — a QS's complete guide

Analysing contractor tenders is one of the most consequential things a quantity surveyor does — and one of the most time-consuming. Done well, it protects the client and your reputation. Done in a hurry, it exposes both to risk. This guide sets out a repeatable method.

Start by normalising the bills

Contractors structure and describe the same work in different ways. Before any comparison is meaningful, every tender must be broken into line items and aligned like-for-like. This is where most of the manual effort traditionally goes: matching equivalent descriptions even when the wording differs.

Compare rates, not just totals

Headline totals hide a multitude of sins. Compare unit rates and section subtotals side by side, and pay attention to rates that sit well above or below the field. Outliers frequently signal a misunderstanding of scope, a loaded rate, or a simple arithmetic error.

Find what's missing

A low tender total can simply mean the contractor hasn't priced everything. Establish which items each contractor did and didn't price, and treat any tender missing a significant share of the scope as potentially incomplete.

Don't ignore qualifications

Qualifications, assumptions and exclusions carry the hidden commercial risk. Capture them, estimate their impact, and bring them into the comparison rather than judging on price alone.

Write a defensible recommendation

Set out your reasoning clearly: how you adjusted items, how you treated qualifications, and why the recommended contractor represents best value. Keep an audit trail back to the source tenders so any challenge can be answered.

TenderCompare AI automates the mechanical steps — extraction, alignment and outlier detection — so you spend your time on judgement, not data entry.