Apples-to-Apples Quote Comparison Explained
The test: same item, same basis, adjustments written down
Two quoted lines can be compared on price only when all three of these are true:
- Same item. The same specification: size, grade, rating, model, standard. N32 concrete isn’t N25. A 5 t excavator isn’t a 13 t excavator. 20mm aggregate isn’t 10mm.
- Same basis. The same unit, quantity, GST treatment and currency, or an exact conversion to them.
- Recorded adjustments. Every conversion or assumption used to get there is written down, so someone else can check it.
Similar wording is not proof
Quotes describe the same thing in different words, and different things in similar words. “Crushed aggregate 20 mm” and “20mm crushed aggregate” are very likely the same. “Drainage gravel 20mm” could be a different product with a different grading and use. A product code, a stated standard or the supplier’s written confirmation is evidence. A shared word or number is a reason to check.
Six ways two lines can relate
Rather than forcing every pair into “same” or “different”, classify each match:
- Exact equivalent
- Same item, same specification, same unit basis.
- Comparable with adjustment
- Same item after an exact, recorded adjustment, such as kg→t, inc→ex GST or a different quantity.
- Conditional match
- Probably the same, but something must be confirmed first, such as a density for m³→t or a product description that differs.
- Not equivalent
- A different specification, grade, size or rating. Not compared on price.
- Missing item
- Quoted by one supplier and not by another. It is flagged, not assumed to be free.
- Uncertain
- There isn’t enough evidence to decide. Shown for your review.
Only exact equivalents and comparable-with-adjustment lines belong in a like-for-like price comparison. Conditional matches wait for confirmation. Not-equivalent, missing and uncertain lines are flagged, not quietly compared.
Unit conversions: exact vs assumed
Conversions within a dimension are exact: kilograms to tonnes, millimetres to metres, days to hours. Conversions across dimensions need a fact that isn’t in the unit itself. That fact has to come from you or the supplier, and it should be labelled as an assumption.
Exact (same dimension) $0.125 /kg × 1,000 kg/t = $125.00 /t inc GST $125.00 ÷ 1.1 = $113.64 /t ex GST Needs an assumption (across dimensions) m³ → t: 10 m³ × 1.5 t/m³ (assumed density) = 15 t bag → kg: $18.00 per 20 kg bag ÷ 20 = $0.90 /kg day → hr: $960 per day ÷ 8 hr/day (assumed) = $120 /hr wk → day: $2,400 per week ÷ 5 days/wk (assumed) = $480 /day
Without the assumption, a price per cubic metre and a price per tonne are not comparable, however close they look. If the density were 1.6 t/m³ instead of 1.5, the 10 m³ above would be 16 t, not 15. That changes the effective rate by more than 6%.
Bundled vs itemised prices
One supplier quotes “supply and install” as a single rate. Another prices material and labour separately. Neither line matches the other directly. The bundled rate covers two components. Compare the bundled total against the sum of the matching itemised lines, and only compare component rates where both suppliers break them out. The example below shows how the engine treats exactly this case: the bundled line is a conditional match to the material line. Supplier B’s separate labour line has no counterpart in Supplier A’s quote, so it’s flagged. But A’s bundle states installation, so A’s complete-scope figure still counts installation as included.
Example data · calculated by the QuantDoc engine
One bundled price vs separately priced supply and labour
What was quoted
- Supplier A: Supply and install 50 m² carpet tiles at $80/m² ex GST ($4,000).
- Supplier B: 50 m² carpet tiles at $45/m² ($2,250) plus installation labour at $30/m² ($1,500), ex GST.
Provisional — check before relying on this: Supplier A: no quoted total to check the lines against; Supplier B: no quoted total to check the lines against. Supplier B has the lowest complete-scope cost at $3,750.00 ($250.00 below the next quote).
Line-by-line matching (2 items)
| Item | Supplier | Match | Normalised rate (ex GST) | Amount (ex GST) |
|---|---|---|---|---|
| Supply and install carpet tiles | Supplier A | Exact equivalent | $80.00 / m² | $4,000.00 |
| Supplier B | Conditional match | $45.00 / m² | $2,250.00 | |
| Installation labour | Supplier A | Missing item | — | Unknown |
| Supplier B | Exact equivalent | $30.00 / m² | $1,500.00 |
| Supplier | As quoted (ex GST) | Like-for-like | Complete scope |
|---|---|---|---|
| Supplier A | $4,000.00 | — | $4,000.00 |
| Supplier B | $3,750.00 | — | $3,750.00 |
2 flags raised · 6 clarification questions drafted
- Supplier B: match needs confirmation
- Supplier A: no matching item for "Installation labour"
How QuantDoc applies this
QuantDoc classifies every line into one of the six classes above and shows its reasons. It converts units only within a dimension unless you enter an explicit assumption (density, pack size, hours per day, days per week), and it records every adjustment beside the figure. You can override a match with a written reason, for example “supplier confirmed same quarry product”. The override is kept in an audit trail.
Next: GST-inclusive vs exclusive quotes, or see a full live example.
Frequently asked questions
What does an apples-to-apples quote comparison mean?
Comparing quotes only on items that are genuinely the same: the same specification, on the same unit, quantity and GST basis, with any adjustment needed to get there written down.
If two items have similar descriptions, are they the same?
Not necessarily. “20mm crushed aggregate” and “drainage gravel 20mm” share a size but may be different products. Similar wording is a reason to check, not proof of equivalence.
Can I convert cubic metres to tonnes?
Only with a density, and density varies by material, grading and moisture. Use a figure confirmed by the supplier and record it as an assumption. Without one, a m³ price and a tonne price can’t be compared directly.
How do I compare a bundled price with itemised prices?
Add up the itemised lines that cover the same scope as the bundled price and compare the totals. Then compare unit rates only where both quotes price the same component separately.
Make the next quote comparison clearer.
Upload competing quotes, check the evidence and see what each option really costs.
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