슬래브, 기초, 기둥, 계단, 포스트 홀에 필요한 콘크리트 부피(yd³ / m³)를 계산하고, 40lb / 60lb / 80lb / 25kg 믹스 포대를 몇 개 구매해야 하는지 확인하세요. 10% 여유분 포함.
| 포대 크기 | 필요한 포대 수 |
|---|
슬래브 / 기초: 부피 = 길이 × 너비 × 깊이. 기둥 / 포스트 홀: 부피 = π × 반지름² × 높이. 계단: 누적 블록으로 근사 계산됩니다 — i번째 단은 상승폭×(i×디딤폭)×너비이며, 모든 단에 대해 합산합니다.
포대당 생산량: 40 lb → 0.011 yd³ (0.30 ft³), 60 lb → 0.017 yd³ (0.45 ft³), 80 lb → 0.022 yd³ (0.60 ft³), 25 kg → 0.0125 m³, 30 kg → 0.015 m³.
10% 여유율은 고르지 않은 지반, 흘림, 약간의 여유 주문분을 감안한 것으로, 주택 타설 작업의 모범 사례입니다.
Three geometries share one output. Slab / footing is length × width × depth. Column / post hole is π × radius² × height, multiplied by your quantity. Stairs are summed as cumulative blocks: step i contributes rise × (i × run) × width, added across every step, which is how a poured monolithic flight actually stacks. Everything is computed in cubic feet, multiplied by 1.10 while the waste toggle is on, then reported as cubic yards (÷ 27), cubic metres (× 0.0283168) and cubic feet.
Watch the unit pairing: in imperial mode the large dimensions are feet while depth, diameter, rise, run and stair width are inches; in metric mode they become metres and centimetres. The default slab is 10 × 10 ft at 4 in deep. The bag table converts your volume against fixed yields — 40 lb at 0.30 ft³, 60 lb at 0.45 ft³, 80 lb at 0.60 ft³, plus 25 kg and 30 kg European sizes — and always rounds up to whole bags.
The 10 percent waste factor is a residential rule of thumb covering spillage and an uneven sub-grade; it is not a substitute for measuring an over-dug footing trench, which can swallow far more. Rebar, mesh and embedded post volume are not deducted, and stair side walls, landings and open risers are not modelled at all. For anything you are ordering ready-mix against, treat the figure as a shopping estimate and confirm with your supplier before the truck is booked.
About 46. The tool uses a yield of 0.022 cubic yards, or 0.60 cubic feet, per 80 lb bag, so a full yard takes 45.5 bags and the table rounds that up. Sixty pound bags need roughly 60, and 40 lb bags about 91.
For most residential pours, yes. It is on by default and multiplies the raw volume by 1.10 to cover spillage, an uneven base and slight over-ordering. Switch it off only when you want the exact geometric volume, for example when checking a supplier's own quote.
Choose the Column / post hole shape. Enter the hole diameter in inches, the depth in feet, and set Quantity to the number of holes. The tool applies π × radius² × height per hole and multiplies through, so all your posts come out in one figure.
No. Stairs are summed purely as stacked rectangular blocks, step by step. Cheek walls, a top landing, a thickened base and any hollow or backfilled void underneath are not included, so a real flight with side walls will need meaningfully more concrete.
Because that is how slabs are specified in practice: a 10 by 10 foot pad at 4 inches deep. The tool converts internally, dividing inch values by 12 and centimetre values by 30.48, so you never have to enter a fractional foot.
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