How to Do a Material Take-Off

Where material estimates actually go wrong

A material cost is two numbers multiplied together: how much you need and what it costs you. Both can be wrong, but they fail differently, and it's worth knowing which one is hurting you.

• Price errors are small and constant. Supplier pricing drifts, and if your list is six months old you're a few per cent light across the board.
• Quantity errors are large and occasional. Miss a whole element — the blocking, the flashings, the second layer of sheeting — and you're not a few per cent out, you're a line item out.

Most tradies worry about the first and get caught by the second. Stale pricing costs you a slow bleed; a missed quantity costs you the job's profit in one hit. Do the take-off properly first, then worry about whether your rates are current.

Doing the take-off

A take-off is just a disciplined list: every material the job consumes, in the unit you buy it in. The discipline is what stops things falling off it.

1. Work through the job in build order. Excavation, footings, frame, roof, external, services, linings, finishes. Following the sequence you'll actually build in is far more reliable than scanning a plan for things you recognise.
2. Measure in the unit you buy in. Not square metres of wall — sheets. Not lineal metres of timber — lengths, in the sizes your supplier stocks. Converting at the end is where rounding errors get baked in.
3. Count the fixings and the fiddly bits as you go. Brackets, straps, bolts, flashings, sealant, membrane, tape. Individually trivial, collectively a real number, and always forgotten if left to the end.
4. Mark anything you can't see. What's under the slab, behind the lining, inside the wall. Flag it as an assumption on the quote rather than guessing silently — an unstated assumption becomes your problem the day it's wrong.
5. Price it from a dated list. Use a current supplier price file, and write the date on it. If a line is volatile — steel, structural timber, concrete, copper — get a fresh price rather than trusting the list.
6. Total it, then read it back. Go through the list once more asking what's missing rather than checking what's there. Those are different questions and only the second one finds gaps.

Waste, and why the allowance should be yours

Every material has a gap between what ends up in the building and what you have to buy. Nobody can tell you what yours is, because it depends on your cutting, your site and the sizes your supplier stocks.

So derive it. For each material type you use often, compare what you took off against what you actually bought over the last several jobs. That ratio is your allowance, and it will be more accurate than any published rule of thumb.

• Sheet materials waste according to how the sheet lands on the layout — the same floor area can be very different depending on room dimensions.
• Linear materials waste according to stock lengths versus the lengths you need. Ordering in the right lengths is often a bigger saving than ordering less.
• Wet trades waste to spillage, over-ordering to avoid a second delivery, and part-bags that go off.
• Fragile and dimensional stock wastes to breakage in transit and handling on site.
• Anything cut to a pattern — tiles, cladding, boards on an angle — wastes far more than the same material laid square.

From cost to quoted price

Your take-off gives you a cost. The price you quote sits above it, and the gap is the part that pays for the buying, the collecting, the storing, the returning and the risk of getting it wrong.

1. Apply margin, not markup. The two are different numbers and mixing them up quietly costs you money on every job. Our guide to working out your charge-out rate sets out the arithmetic — use the same convention on materials as you do on labour.
2. Put a validity date on the quote. Material pricing moves. A quote that's open-ended is a promise to hold today's supplier price for as long as the client takes to decide.
3. Use provisional sums where the scope isn't settled. Fittings and finishes the client hasn't chosen belong as a stated allowance, with what happens if they pick something dearer written down.
4. State your exclusions. What the price doesn't cover — rock, contaminated fill, upgrades required once things are open. See quote vs estimate for where the line sits.
5. Itemise enough to defend it. You don't have to hand over your take-off, but a quote with material groups shown survives a comparison against a cheaper number far better than a single total does.

Check yourself against the finished job

None of this improves unless you close the loop. When a job finishes, put what you actually spent on materials next to what you allowed, line by line where you can.

• One job over is a bad day. The same line over on three jobs is a wrong allowance, and it will keep being wrong until you change it.
• Look for the line that's always short, not the total. A take-off that comes out right overall can be hiding one item you consistently under-order and one you consistently over-order.
• Check what came back. Surplus returned is a signal your quantities are generous; surplus in the shed is a signal you paid for stock you didn't need.
• Update the price list from real dockets, not from memory of what things used to cost.

Frequently asked questions