How to Compare Subcontractor Quotes

Start with the scope, not the totals

The single most common mistake when comparing subcontractor quotes is reading the bottom line first. A total is only meaningful once you know what it covers. Before you open the quotes, write down the scope you asked each subcontractor to price: the drawings and specification revision, the trade package boundaries, who supplies what, and the attendances you expect (cranage, scaffolding, waste removal, temporary services, cleaning).

If the subcontractors priced different document revisions, stop and fix that first. No amount of spreadsheet work will make quotes for different drawings comparable.

Step 1: Break each quote into the same components

List every line in each quote and assign it to a component of your scope. A plumbing package might break into sanitary drainage, hot and cold water, fixtures supplied, fixtures installed, testing and commissioning, and authority fees. An itemised quote maps easily; a lump sum needs its description and inclusions read carefully to decide which components it claims to cover.

Where one subcontractor bundles supply and installation into a single rate and another prices them separately, compare at the level both share. In the worked example below, Supplier A quotes supply and install as one rate while Supplier B splits material and labour:

Supplier A: 50 m² × $80.00/m² (supply and install) = $4,000.00 ex GST
Supplier B: 50 m² × $45.00/m² (supply) = $2,250.00
           50 m² × $30.00/m² (labour) = $1,500.00
           Total = $2,250.00 + $1,500.00 = $3,750.00 ex GST
Difference = $4,000.00 − $3,750.00 = $250.00 in B’s favour

Step 2: Read the exclusions and qualifications

Exclusions are where most of the real difference between subcontractor quotes lives. Read every exclusion, qualification, assumption and “by others” note, and mark which of your scope components each one removes. Common ones include builder’s work in connection, penetrations and fire sealing, after-hours work, authority fees, crane hire, and making good.

An exclusion turns a component from “priced” into “you will pay for this separately”. It does not make the component free.

Step 3: Put every quote on the same basis

• GST: convert all prices to ex GST (or all to inc GST). $11,000 inc GST ÷ 1.1 = $10,000 ex GST.
• Units: metres vs linear metres vs lengths, m² vs “per room”. Only convert when the conversion is exact or you state the assumption.
• Quantities: if one subcontractor measured 180 m and another 200 m, compare rates and ask about the quantity. A lower total built on a short measure is not a saving.

Step 4: Price the gaps, or show the break-even

When one quote leaves out a component, you have two honest options: get a price for it, or work out the break-even. The break-even is the most the missing component can cost before the cheaper-looking quote stops being cheaper:

Break-even = complete price of the fully priced quote − known price of the incomplete quote
Example: $32,200.00 − $27,000.00 = $5,200.00
If the excluded item costs more than $5,200.00 ex GST, the ‘cheaper’ quote is dearer.

Step 5: Ask, in writing, before you award

Turn each gap into a specific question for the relevant subcontractor: “Your quote excludes penetrations through fire-rated walls. Please price fire sealing to the 12 penetrations shown on drawing H-201 or confirm it is by others.” Specific questions get specific answers, and the replies become part of your record.

Step 6: Record the decision

Keep a short record of what was compared, what was assumed and why the chosen quote won. It protects you if the job goes sideways and saves time on the next tender. Contractual questions such as whether a qualification shifts risk are issues for professional review, not something a spreadsheet can settle.

Where QuantDoc fits

QuantDoc does steps 1 to 5 from the quotes you upload: it extracts each line with a page or row reference, classes matches (exact, comparable with adjustment, conditional, not equivalent, missing, uncertain), normalises GST and units, flags exclusions and unknowns, shows break-even thresholds, and drafts clarification questions for you to send. The example below was calculated by the same engine.