Construction estimating, done in seconds

1. Concrete estimator

For a rectangular slab. Enter length, width and depth in the selected system.

Formula: volume = length x width x depth. Volume with waste = volume x (1 + waste / 100). Bags = volume with waste / 0.0135. Bag yield stated: one 30 kg pre-mix bag yields about 0.0135 cubic metres. 1 cubic metre = 1.30795 cubic yards.

Trade hub: Concrete pack with calculator, pre-job checklist and material list

2. Drywall estimator

Formula: sheets = ceiling of (area with waste / sheet area). Screw assumption stated: about 32 screws per 4 x 8 ft sheet and 48 screws per 4 x 12 ft sheet, about 1 screw per square foot. Joint compound guidance: about 1 box (4.5 gallon size) per 400 sq ft of board area, actual use varies with joints and finish level.

Trade hub: Drywall pack with calculator, pre-job checklist and material list

3. Deck materials estimator

Boards run along the deck length. Joists at 400 mm / 16 in centres.

Formula: boards = ceiling of (deck width / (board width + gap)). Linear length = boards x deck length. Joists = ceiling of (deck length / 0.4 m) + 1. Screws = boards x joists x 2 screws per crossing.

Trade hub: Deck pack with calculator, pre-job checklist and material list

4. Framing lumber estimator

Formula: field studs = ceiling of (wall length / spacing) + 1 end stud. Assumption stated: add 2 extra studs as a corners and intersections allowance. Plates: 3 rows total (1 bottom plate plus double top plate), reported as linear length. Openings for doors and windows are not deducted and need extra framing, so treat this as a starting estimate.

Trade hub: Framing pack with calculator, pre-job checklist and material list

5. Project bid helper

Estimating aid only, not accounting advice.

Formula: labour cost = hours x rate. Direct cost = materials + labour. Break-even bid = direct cost x (1 + overhead / 100). Bid at target margin = break-even / (1 - margin / 100).

More free BuildTrue estimators

• Calculate tiles, boxes and grout for a floor or wall: tile size, waste allowance, and epsilon safe counts.
• Calculate paint litres and cans for a room: wall area after doors and windows, coats, and coverage.
• Calculate shingle bundles, squares and underlayment rolls: roof area adjusted for pitch and waste.
• Calculate gravel volume, weight and 25 kg bags: for beds, paths, and drainage layers.
• Calculate board feet for a lumber order: board feet per board and per order from actual dimensions, quantity, and waste.
• Calculate batt packages or blown insulation bags: wall or attic area, target R value, and waste.
• Calculate flooring boxes and planks: hardwood, laminate, and vinyl plank by area and box coverage.
• Calculate fence posts, rails, pickets or panels: by run length, post spacing, and style.
• Calculate footing tubes, concrete volume and bags: sonotube diameter, depth, and footing count.
• Calculate stair risers, treads and stringer length: riser count, total run, and a Canadian model code check.

Trade packs

• Concrete pack: calculator, checklist and material list
• Drywall pack: calculator, checklist and material list
• Deck pack: calculator, checklist and material list
• Framing pack: calculator, checklist and material list
• Roofing pack: calculator, checklist and material list
• All trade packs: five trade hubs with calculators, pre-job checklists and printable material lists.

BuildTrue: Construction Estimating Hub

Guides in this hub

• How to Estimate Concrete for Any Job
• Drywall Estimating: Sheets, Screws, and Compound Without the Guesswork
• Building a Bid: From Takeoff to Price
• BuildTrue frequently asked questions

BuildTrue is a Mississippi Maple unit built for one job: helping Canadian contractors and serious DIYers estimate with confidence. No hype, no shortcuts that fall apart on site. Just clear math, practical allowances, and tools that show their work so you can check every number before you order, quote, or pour.

Estimating looks simple on paper. Length times width times depth. Wall area divided by sheet size. Studs spaced across a wall. In practice, jobs rarely fail because the basic formula was wrong. They fail in the gaps around the formula: the waste nobody added, the rounding nobody planned for, the small consumables nobody listed, and the hour of labour nobody counted. This hub exists to close those gaps.

Why estimates go wrong

1. Waste is treated as optional

Every material has waste. Concrete spills, over excavates, and settles into uneven subgrade. Drywall sheets get cut around doors, windows, outlets, and corners, and offcuts are not always usable elsewhere. Lumber arrives with a split end, a bow, or a cut that was measured once and made wrong.

Waste is not a sign of poor work. It is a normal part of building. The mistake is ordering to the exact theoretical quantity and hoping the site will be perfect. It will not be. A good estimate names a waste allowance on purpose, explains why that allowance was chosen, and keeps it separate from the base quantity. That way, if you need to trim a bid, you can see exactly what you are risking.

Cut heavy work needs more allowance than simple work. A plain rectangular slab needs less extra than a slab with steps, thickened edges, and grade changes. A single large room needs less drywall waste than a bathroom full of bulkheads and niches. Match the allowance to the complexity, not to habit.

2. Rounding works against you

Suppliers do not sell fractions the way calculators produce them. Ready mix concrete is ordered in increments. Bags come whole. Sheets come whole. Lumber comes in standard lengths.

Rounding down to save a few dollars is false economy if it leaves a crew waiting, a second delivery fee, or a half finished wall. Rounding up is not wasteful when it is planned. It is how you buy in real units. Good estimating rounds at the ordering stage, not at the measuring stage, and it rounds length choices intelligently. For example, choosing a longer board that yields two needed pieces can beat buying two shorter boards, if the cuts work out.

Unit conversion is another rounding trap. Canadian jobs are measured in metric on drawings and often sold in imperial units at the counter. A small conversion error repeated across a whole order becomes a large shortage or surplus. Work in one system through the takeoff, then convert once, carefully, at the end.

3. Forgotten consumables quietly erase margin

The big materials get all the attention. The small ones decide whether a job was profitable.

Concrete work also needs form lumber, stakes, rebar or mesh where specified, chairs, tie wire, curing supplies, and often a pump or extra wheelbarrow labour. Drywall also needs screws, tape, compound, corner bead, and sanding supplies. Framing also needs nails, hangers, connectors, and sheathing fasteners. Decks also need footings, post bases, joist hangers, flashing, and fasteners rated for the lumber and exposure.

None of these items is expensive alone. Together, and repeated across jobs, they matter. List consumables as their own line in every takeoff, even if the line starts as a prompt to check. A prompt you review beats an item you forget.

4. Labour and site conditions are guessed, not estimated

A material count is not a bid. Labour depends on access, height, weather protection, demolition, disposal, and how many interruptions the site will create. Carrying sheets up stairs is not the same job as loading them into a ground floor garage. Pouring a pad with truck access at the forms is not the same job as wheeling every load down a side yard.

BuildTrue separates the two questions on purpose. First, how much material does the work require? Second, what time, overhead, and margin turn that material list into a responsible price? Keeping those steps separate makes errors easier to find and conversations with clients easier to have.

The five BuildTrue calculators

Use the tool that matches the decision in front of you. Each calculator is free to use and built to show quantities in units you can order.

Concrete estimator

For slabs, pads, footings, and simple walls. Enter dimensions, get volume in cubic metres and cubic yards, plus a bag count for smaller jobs so you can compare bagged mix to ready mix with real numbers.

Try it here: Calculate concrete for your slab or footing

Best for: shed pads, hot tub pads, garage slabs, fence and deck footings, small retaining elements where volume drives the order.

Drywall estimator

For walls and ceilings. Enter room dimensions or total area, choose a sheet size, and get a sheet count with room for waste. It helps you compare 4 ft by 8 ft sheets that are easier to handle against 4 ft by 12 ft sheets that create fewer joints on long walls.

Try it here: Estimate drywall sheets for a room

Best for: basements, garages, additions, and single room renovations where cut waste varies a lot from room to room.

Deck materials estimator

For deck boards, joists, beams, posts, and footings as a coordinated list, not a guess based only on deck area. Deck geometry creates waste and hardware needs that area alone will miss.

Try it here: Build a deck materials list

Best for: planning a new deck, comparing board layouts, and checking that structural pieces and connectors are on the list before you price the job.

Framing lumber estimator

For stud walls and basic framing takeoffs. Enter wall length, height, and stud spacing, and get stud counts and lumber quantities you can adjust for doors, windows, corners, and top plates.

Try it here: Count framing studs and lumber

Best for: partition walls, basement framing, sheds, garages, and addition walls where spacing and openings change the count quickly.

Project bid helper

For turning a takeoff into a price. Enter materials, labour hours and a labour rate, an overhead percent, and a margin percent, and see the steps laid out in order. It is an estimating literacy tool, not a substitute for your own costs. Your real overhead, your real crew rates, and your target margin are inputs only you can supply accurately.

Try it here: Turn a takeoff into a bid

Best for: checking a quote before it goes out, testing what happens when scope changes, and learning the difference between markup and margin with your own numbers.

A practical workflow, from takeoff to bid

Step 1: Define the scope in writing

What is included, what is excluded, and what is assumed? Dimensions, thickness, finishes, access, demolition, and disposal should be stated before numbers start. Most estimating disputes are scope disputes that were never written down.

Step 2: Measure once, in one system

Work metric first. Record length, width, height, and thickness as measured, not as remembered. Sketch irregular areas and break them into rectangles and triangles you can calculate. Keep openings and deductions visible as separate lines so a reviewer can follow them.

Step 3: Calculate base quantities

Use the matching BuildTrue calculator for the base quantity. Write down the formula result before waste and before rounding. That base number is your audit trail.

Step 4: Add waste and consumables, on purpose

Add a waste allowance that fits the complexity of the work. Then add consumables as their own list: fasteners, connectors, tape, compound, form materials, and disposal supplies as they apply. Do not bury these inside a vague contingency if you can name them.

Step 5: Convert and round for ordering

Convert to supplier units once. Round sheets, bags, and boards up to whole units. Choose lumber lengths based on your cut list, not just total length. Note the order quantity beside the base quantity so the difference is explained.

Step 6: Price labour, overhead, and margin separately

Estimate labour hours from the actual tasks: layout, preparation, installation, finishing, cleanup, and travel where it applies. Apply your labour rate. Add overhead recovery to cover the costs of running the business that are not tied to one job, such as insurance, vehicles, tools, and administration. Then apply margin as a percent of the final price, not as a casual add on. The bid helper shows this order clearly.

Step 7: Review before you send or order

Check three things. Does the scope match the quantities? Does the order quantity match the supplier units? Does the price include labour, overhead, and margin as separate, visible steps? If any answer is unclear, fix it now. It is cheaper than fixing it on site.

Who this hub is for

Contractors who want faster, more consistent takeoffs without giving up control of their numbers. Serious DIYers who want to order once, order correctly, and understand what a fair bid includes when they hire work out. Estimators in training who need the reasoning behind the math, not just an answer.

BuildTrue will keep growing this hub with worked examples that show every step. If a number on this site cannot be traced back to a measurement and a formula, it does not belong here.

Sources and figures note

Dimensions and material properties in BuildTrue examples are stated as example inputs for the calculation shown. Building requirements for footings, stairs, guards, and structural framing vary by province and municipality and are governed by the applicable provincial building code and local bylaws. Verify local code and permit requirements before you build. Supplier yield and coverage figures vary by product: check the bag, sheet, or product data sheet for the specific product you plan to buy before ordering.

Frequently asked questions