Concrete Calculator: Beam (Rectangular / T-Beam) — Volume & Bags
Estimate concrete for prismatic beams. Choose a rectangular beam or a T-beam, enter section dimensions once, then list one or more beam runs (lengths). Add a waste allowance and get per-beam volume, total volume (m³, yd³, ft³), and approximate bag counts. Notes, formulas, and FAQs included.
Results
Section
Area: 0.0000 m²
—
Totals
Total length: 0.000 m
Net volume: 0.000 m³
With waste: 0.000 m³
0.000 yd³ • 0.00 ft³
Per-run volumes
| # | Length | Volume |
|---|
Approximate bag counts (total with waste)
US bag sizes (QUIKRETE® yield)
Yields per bag from QUIKRETE data sheet. Actual yield varies with placement and compaction. Source
Metric bag sizes
Edit yields to match your local supplier data.
How to use this beam calculator
- Select metric or US units.
- Choose the beam type and enter section dimensions.
- Enter the number of beam runs and fill in each beam length.
- Add a waste allowance (many projects use 4–10%).
- Review per-run volumes, totals, and bag counts. Round up for ordering.
Formulas and assumptions
- Rectangular beam: section area
A = b × h. - T-Beam: section area
A = bf × tf + bw × (h − tf)(ensuretf ≤ handbw ≤ bf). - Per-run volume:
V = A × L. - Totals:
Vtotal = ΣV, with wasteVw = Vtotal × (1 + waste%). - Scope: Gross concrete only—does not deduct steel volume, ducts, or block-outs, and does not design reinforcement or shear keys (see design codes such as ACI 318 / Eurocode 2).
References
- T-beam concept and geometry overview: T-beam.
- Concrete waste allowance ~4–10%: NRMCA Concrete In Practice CIP 8, CIP 31.
- US bag yields: QUIKRETE® Concrete Mix 1101 data sheet.
FAQs
What if my beam has varying depth or haunches?
This version assumes constant section along the length. For tapered or haunched beams, split the beam into zones or ask for a frustum/segmented variant.
Does this account for reinforcement and ducts?
No. Steel, ducts, and block-outs slightly reduce net concrete. For ordering, many treat them as negligible, but you can subtract their volume if needed.
Is cover or code sizing included?
No. This is an estimating tool only; follow your structural drawings and local code (e.g., ACI 318 / Eurocode 2) for dimensions and reinforcement.