Site Calculators

🧮
Civil Engineering Calculators
Steel • Concrete • Bricks • Shuttering • Land • Cost
22 toolsm / ftFree
📏 Units
mm sizes stay in mm

🔩 TMT Bar Weight Calculator

Weight (kg/m) = D² ÷ 162  (D in mm)
Dia (mm)kg per metrekg per 12 m barBars per tonne (12 m)

⚖️ Metal Weight Calculator (Steel, Aluminium, SS…)

Weight = cross-section area × length × density

Channels and I-beams are worked out from plate dimensions (no root fillets), so they are approximate. For standard ISMB, ISMC and ISA sections, use the weights in IS 808.

🏗️ Concrete Quantity Calculator (Nominal Mix)

Dry volume = wet volume × 1.54  |  1 bag cement = 50 kg = 0.0347 m³

Nominal mixes as per IS 456 (Table 9) up to M20. *M25 (1:1:2) is a common site practice; for M25 and above, IS 456 recommends a design mix (IS 10262). Add 2–5% for wastage.

🧱 Brickwork / Block Calculator

Bricks = wall volume ÷ volume of one brick with mortar

Common sizes: conventional brick 230×110×75 mm, modular brick 190×90×90 mm, AAC block 600×200×(100–200) mm with 3–5 mm adhesive joints.

🪣 Plaster Calculator

Dry mortar = area × thickness × 1.33 (allows for joints, voids and wastage)

🔲 Tiles & Flooring Calculator

Tiles = floor area ÷ area of one tile + wastage

🎨 Paint Calculator

Paint (litres) = area × coats ÷ coverage per litre

Coverage depends on the brand and surface. Check the paint tin; rough surfaces need more paint.

🔗 Development Length & Lap Length (IS 456)

Ld = φ × 0.87 fy ÷ (4 τbd)

τbd for deformed (TMT) bars = plain-bar value × 1.6; in compression, increased by a further 25% (IS 456, Cl. 26.2.1.1). Lap in flexural tension = greater of Ld and 30φ; lap in compression = greater of Ld (compression) and 24φ (Cl. 26.2.5.1). Avoid laps at points of maximum stress and stagger them.

⛏️ Earthwork / Excavation Calculator

Volume = L × D × (B + n·D)  (n = side slope, horizontal : 1 vertical)

💧 Water Tank Capacity Calculator

1 m³ = 1000 litres

135 litres per person per day is the usual domestic demand for cities with full flushing systems (NBC / IS 1172). Leave about 150 mm free board above the water level.

📐 Steel Quantity in RCC

Steel (kg) = concrete volume × steel % ÷ 100 × 7850

Slab mesh (exact bars)

Steel % values are typical thumb rules for estimating only. Actual steel comes from the structural drawings / bar bending schedule. The slab mesh assumes main bars run along the shorter span; add hooks, cranks and laps as per the drawing.

🧾 Bar Cutting Length (BBS)

Rectangular stirrup

Cutting length = 2(a + b) + 2 × 10φ (hooks) − 3 × 2φ (90° bends) − 2 × 3φ (135° bends)

Bent-up (crank) bar

Cutting length = straight length + 2 × 0.42H − 4 × 1φ (four 45° bends)

Bend deductions (45° = 1φ, 90° = 2φ, 135° = 3φ) and hook lengths are common site practice; follow your drawings and IS 2502 / SP 34 where specified.

🧪 Concrete Mix Design (M20–M40)

Target strength = fck + 1.65 s

A first estimate for trial mixes (IS 10262 method with IS 456 limits). Always confirm with trial mixes and cube tests in the lab before use.

🏛️ Footing & Column Concrete

Sloped part = h/3 × (A1 + A2 + √(A1 × A2))

🧊 Cube Compressive Strength

Strength (N/mm²) = load (N) ÷ area (mm²)

Cement: minimum strength as per IS 269 / IS 1489. Concrete: % of fck shown against typical strength gain only; acceptance of concrete is judged as per IS 456 (Cl. 16) on groups of results.

🪵 Shuttering Area & Removal Dates

A. Shuttering area

B. When to remove formwork (IS 456, Cl. 11.3.1)

Times are for OPC concrete and ordinary weather (above 15 °C) as per IS 456. For slow-hardening cements (PPC, PSC) or cold weather, keep the formwork longer, as decided by the engineer-in-charge. Re-prop slabs and beams if loads come early.

🪜 Staircase Calculator

Risers = floor height ÷ riser  |  comfort check: 2R + T ≈ 550–700 mm

NBC 2016 (residential): riser not more than 190 mm, tread not less than 250 mm, clear width at least 1.0 m (0.9 m for low-rise houses). Concrete shown excludes landings.

📏 Slope & Gradient Converter

Slope % = rise ÷ run × 100  |  angle = tan⁻¹(rise ÷ run)

Typical values: road camber 2–2.5% (bituminous), roof drainage 1 in 100 to 1 in 120, ramps for wheelchairs 1 in 12, drains 1 in 300 to 1 in 1000.

🌾 Land Area Converter (Acre – Kanal – Marla – Gaj – Bigha)

1 Acre = 8 Kanal = 160 Marla = 4840 Gaj = 43,560 sq ft

Marla = 272.25 sq ft (Karam of 66 inches), as used in Punjab and Haryana revenue records. Bigha and Biswa differ from state to state; Punjab values are used here (1 Bigha = 9,075 sq ft).

🔄 Engineering Unit Converter

🏠 House Construction Cost & Materials

Cost = built-up area × rate per sq ft

Material quantities are common thumb rules for an RCC framed house (per sq ft of built-up area): cement 0.4 bag, sand 1.816 cft, aggregate 1.35 cft, steel 4 kg, bricks 8 nos, paint 0.18 litre, tiles 1.3 sq ft. The cost split is a typical average. Rates vary by city, design and finish; use this only as a first estimate.

📋 Unit Weights of Common Materials

MaterialUnit weight
Reinforced cement concrete (RCC)25 kN/m³ (2500 kg/m³)
Plain cement concrete (PCC)24 kN/m³ (2400 kg/m³)
Brick masonryabout 19–20 kN/m³
Steel78.5 kN/m³ (7850 kg/m³)
Aluminium27 kN/m³ (2700 kg/m³)
Cement (loose)14.4 kN/m³ (1440 kg/m³)
Sand (dry, loose)about 15–16 kN/m³
Coarse aggregate (loose)about 15–16 kN/m³
Water9.81 kN/m³ (1000 kg/m³)
Glassabout 25 kN/m³

Typical values; for design, use IS 875 (Part 1).

⚠️ Note: these calculators give quick estimates for planning and checking. For final quantities, designs and payments, follow the drawings, the relevant IS code and your contract.