Concrete volume on the phone, before you order

Running short on a pour stops the crew and can cost a return truck. Ordering far too much burns cash and leaves waste on site. A fast concrete calculator is the habit that keeps both problems rare. Enter the size of the pour, set a waste percent, and read volume in cubic metres plus bag counts that round up so you are not one bag short on a small pad.

This tool is built for Canadian trades working from a phone in the truck or on the pad. Metric is the default because ready mix plants in Canada quote and deliver in cubic metres. Switch to imperial when the drawing is in feet. Use it for garage pads, sidewalks, shed bases, fence post piers, sonotube style columns, and strip footings.

How the concrete calculator works

For a slab or footing the volume is length times width times thickness (or depth). For a round column the volume is pi times radius squared times height. Quantity multiplies identical pieces. All inputs convert to metres under the hood so cubic metres stay consistent whether you type metres or feet.

Waste multiplies the raw volume. Ten percent is a common start for simple pads. Increase it for rough excavation, uneven subgrade, many small piers, or when the chute will waste more. Bag count uses typical bag yields and always rounds up to whole bags. Ready mix orders should still follow your plant minimum and your structural mix design.

Metric cubic metres vs bags

On larger pads and footings most Canadian crews order ready mix in cubic metres. This calculator shows m³ first so you can call the plant with a clear number. For small pads and repairs many yards sell 30 kg bags. You can also pick 40 lb, 60 lb, or 80 lb bags if that is what you stock. Yields are typical only. Always read the bag label for your brand and mix.

Cubic yards and cubic feet appear as well for drawings or suppliers that still talk imperial. Use them as a cross check, not as a second source of truth when the plant wants cubic metres.

Common pours this tool covers

Slabs and pads: garage floors, shed bases, sidewalk sections, equipment pads. Enter length, width, and thickness. Thickness of 100 mm (about 4 in) is common for light pads. Confirm structural depth with the engineer or local practice for driveways and heavy loads.

Footings and trenches: strip footings under walls and trench fills. Use length along the trench, width of the footing, and depth. Quantity can cover multiple equal runs.

Columns and rounds: sonotube style piers and round footings. Enter diameter and height (depth into the ground or above grade as required). Quantity covers a row of matching posts.

Waste factor tips from the field

Five to ten percent suits clean forms and a level subgrade. Bump waste when the excavation is oversized, the form leaks, you have many corners, or the truck cannot place tight to the pour. Bag mixes often need a little extra for cleanup and uneven mixes. The calculator multiplies by your percent so you stay in control of the allowance.

Never use a web estimate alone for structural concrete. Soil conditions, rebar congestion, and form bounce change real volume. Walk the dig with a tape before you lock the order.

Print, share, or save to Docs

Results stay at the top of the tool so you see the number while you tweak sizes. Print or PDF gives you an A4 style sheet for the plant, the helper loading bags, or the job file. Share sends the estimate (and PDF when the phone allows) to a coworker or supplier. Signed in users can save a frozen tool sheet into TradeInvoice Docs next to quotes and invoices. Saved numbers do not change later if we improve the formulas.

When you are ready to price labour and materials for the customer, open the free quote generator and build a proper quote with tax for your province.

Quick example

A slab 3 m by 2 m by 0.10 m is 0.60 m³ before waste. With 10% waste you need about 0.66 m³. That is what you tell the ready mix plant for a small pad, subject to their minimum load. If you bag mix with 30 kg bags, the bag count rounds up from that volume using the yield in the tool. Always confirm bag yield on the package.

Frequently asked questions

Is this concrete calculator free?

Yes. Calculate, print, PDF, and share without an account. Saving the sheet to Docs needs a free TradeInvoice account.

Does it work for Canadian ready mix orders?

Yes. The main volume is cubic metres, which is how most Canadian plants sell and deliver. You also get cubic yards and cubic feet for cross checks.

Should I use metric or imperial?

Use metric when plans and plant tickets use metres. Use imperial when the drawing is in feet. For inches, convert to decimal feet (4 in is about 0.33 ft) or convert the plan to metres first.

What waste percentage should I use?

Many crews start at 5 to 10 percent for simple slabs. Use more for rough digs, many piers, or messy placement. The tool multiplies volume by the percent you set.

Are bag counts exact?

No bag count from a website is exact. Yields differ by brand and mix. Counts round up using typical yields so you have a safe order size. Confirm with the bag data sheet before a critical pour.

Can I print or share the result?

Yes. Use Print or PDF for an A4 style sheet. Share uses the phone share sheet when available, including the PDF file when the device supports it.

Will saving to Docs count as a document?

Yes. Saved tool sheets use your account document limit the same way quotes and invoices do on the free plan.

Does this replace an engineer or mix design?

No. It estimates volume and bags for ordering. Structural depth, rebar, psi, and mix design come from drawings, codes, and your supplier.