Brick Quantity Calculator for Walls
Wall area in m² times bricks per m², plus a waste percentage and rounded up: 20 m² at 25 bricks per m² with 7 percent waste needs 535 units.
Bricks
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Bricks per square meter of wall
Take the wall area, multiply it by how many bricks fit in a square meter for the unit you picked, then tack on some loss. Here are the indices you'll see most often: 6-hole ceramic brick 9×14×19 cm → ~25/m²; 8-hole brick 19×19×9 cm → ~22/m²; concrete block 14×19×39 cm → ~12.5/m²; solid brick → ~62/m². Say you have a 20 m² wall and you're laying 6-hole brick: 20 × 25 = 500 bricks. Add 5–10% loss for cuts and breakage and you'll want to buy 525–550 units. Those indices already account for the standard 1 cm mortar joints.
Applications and standards
People reach for this when they're pricing a job at Leroy Merlin, Cassol, Telhanorte, paying a bricklayer by the m², sizing up a self-build, or working out how much material to have delivered. On the standards side, NBR 15812 covers structural masonry made of ceramic blocks, and NBR 15270 lays out the requirements for ceramic brick itself. If the wall carries load, defer to the structural project. Sealing masonry, which isn't structural, just fills in the frame.
FAQ
Why include loss? Between cuts at corners, work around openings, things breaking in transit and the odd misaligned course, you lose 5–10%. A renovation full of cuts can push that to 15%.
Do I subtract doors and windows? Yes. Take the opening area out of the total wall area first, then apply the index.
Ceramic or concrete block? Ceramic runs lighter and costs less per unit. Concrete block is stronger and more uniform, which is why structural masonry tends to favor it.
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Silo Horizontal Pressure (Janssen)
Calculate the horizontal pressure the stored product exerts on a silo wall by the Janssen equation, p_h = (γ·D)/(4·μ)·(1 − e^(−4·μ·K·z/D)), from the unit weight γ, diameter D, product-wall friction coefficient μ, lateral pressure ratio K and depth z. Horizontal pressure is the outward thrust grains apply against the silo walls — the load that sizes the wall for hoop tension (in cylindrical silos, the wall acts as a ring under internal pressure). It relates to vertical pressure by the lateral pressure ratio K (p_h = K·p_v), typically 0.3-0.6 for granular products and depending on the product's internal friction angle. Like vertical pressure, horizontal pressure tends to an asymptotic value with depth, by the same wall-friction effect of Janssen theory. Horizontal pressure is decisive for the thickness and reinforcement of concrete silo walls and the plating of steel silos, and rises significantly during DISCHARGE (dynamic overpressure), which codes handle with amplification factors. Enter the unit weight, diameter, friction coefficient, lateral pressure ratio and depth.
Thickness/Diameter Ratio (Thin Wall)
Calculate a pressure vessel's thickness/diameter ratio, t/D, from the wall thickness t and the diameter D (same unit). This ratio is the criterion deciding whether a vessel can be treated as THIN-walled or needs THICK-walled (Lamé) theory. The distinction is fundamental because the formulas change: in THIN walls (rule of thumb t/D < 0.05, or t/r < 0.1), stress is practically UNIFORM across the thickness, and the simple membrane formulas hold (σ = P·r/t for hoop) — the case of the vast majority of vessels, pipes and tanks. In THICK walls (larger t/D, as in very-high-pressure vessels — hydrogenation reactors, gun barrels, high-pressure hydraulic tubing), stress VARIES strongly across the thickness (maximum at the inner surface, decreasing outward), and the simple formulas dangerously underestimate the inner peak stress — Lamé's equations must be used. Checking the t/D ratio is thus the first step in choosing the correct calculation theory. Vessels with t/D above ~0.1 require thick-wall analysis. This simple check avoids the serious error of applying thin-wall formulas to a thick vessel. Enter the thickness and the diameter.
Cooling Time (Injection Molding)
Estimate the cooling time of a flat part in injection molding, t = h² ÷ (π²·α), from the wall thickness h and the polymer's thermal diffusivity α. The result, in seconds, is the dominant time of the injection cycle — the part can only be ejected after cooling enough to be rigid. The most critical factor is thickness squared: doubling the thickness quadruples the cooling time (and the cost per part). That is why thin, uniform walls are a golden rule in injection part design. Plastics' low thermal diffusivity makes cooling the productivity bottleneck. Enter the wall thickness and the thermal diffusivity.
Wallpaper Roll Calculator
Calculate how many wallpaper rolls to buy to cover a wall, from the room and roll dimensions. Includes the allowance for pattern matching and cuts.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.