Shuttering Area Calculation: Formula for Footing, Column, Beam, Slab and Stairs

How do you calculate shuttering area?

Measure only the faces of concrete that touch the shutter, in square metres. That is the rule in clause 6.1 of IS 1200 (Part 5):2013, the Bureau of Indian Standards method of measurement for formwork: formwork is measured as “the actual surfaces in contact with the concrete”. Each dimension is taken to the nearest 0.01 m and each area worked out to the nearest 0.01 m² (clause 2.4).

Three habits keep a take-off honest. Work member by member, because the standard keeps footings, columns, beams, slabs and stairs as separate items (clause 5). Keep work below the ground or datum level apart from work above it (clause 2.7). And never add a face that nobody shutters. The top of a slab, a footing or a beam is open when the concrete goes in.

Table 1: Shuttering area formula for each member (b = width, d = depth of column, D = overall depth of beam, t = slab thickness, L = length, h = height)

How do you calculate shuttering for a footing?

Measure the vertical sides of the footing and nothing else. The bottom sits on the PCC bed or the soil, which does the job of a mould, and the top is open. So for a plain rectangular footing, often called a box footing: shuttering area = 2 × (L + B) × D, where D is the depth of the footing.

A stepped footing is two or three boxes stacked on each other, and the sides of every step are measured. A sloped footing is different. This is the trapezoidal kind, with a top that slopes up towards the column, and it is shuttered only on the short vertical edge at its base. IS 1200 treats a sloping surface of up to 30° as needing a shutter on its underside only (clause 5d), and a footing has no underside to shutter. A gentle slope is therefore finished by hand with a stiff mix. If your drawing shows a slope steeper than 30° and the engineer asks for top shutters, measure those too, because they touch the concrete.

Table 2: Three footing shapes and their shutter faces

Footings are an item of their own (clause 5a), and work in water or liquid mud is measured separately (clause 2.5), which matters when a trench keeps filling from a high water table.

The concrete in the footing is a separate sum. The building material calculation guide turns that volume into cement, sand and aggregate, and PCC vs RCC explains why the bed under the footing is plain concrete.

How do you calculate shuttering area of a column?

Multiply the girth of the column by its shuttered height. Girth is the distance round the outside. For a rectangular column it is 2 × (b + d), so a 230 × 300 mm column has a girth of 2 × (0.23 + 0.30) = 1.06 m and carries 1.06 m² of shutter for every metre of height. For a round column use π × diameter: a 300 mm round column carries 0.94 m² per metre. IS 1200 keeps square, rectangular, circular and curved columns as separate items (clause 5k), because a round shutter takes more work.

Height is where take-offs disagree, and the standard settles it. Since Amendment 1 of February 2020 the rule sits at the end of clause 6.1 (it used to be clause 6.6): a beam is measured only up to the sides of the column, and nothing is deducted from the column casing where a beam runs into it. So measure each column from the top of the footing, or the floor, up to the underside of the slab, and stop every beam at the column face. Done that way, nothing is counted twice and no strip is missed.

Keep the part below the plinth on its own line (clause 2.7); in the house example below, the 1.2 m under the plinth is booked apart from the 2.875 m above it.

Table 3: Shutter area per metre of column height

How do you calculate shuttering area of a beam?

Add the two sides and the bottom, then multiply by the beam’s clear length between columns. Under a slab there is one catch: the sides are measured only from the underside of the slab downwards, because the slab’s own shutter covers the top part. That gives two formulas.

• Interior beam (slab on both sides): [2 × (D − t) + b] × L
• Edge beam (slab on one side, open face outside): [D + (D − t) + b] × L. The outer face runs the full depth, and it also forms the edge of the slab.

For a 230 × 450 mm beam under a 125 mm slab, D − t is 0.325 m. An interior beam then carries 2 × 0.325 + 0.23 = 0.88 m² per metre, and an edge beam 0.45 + 0.325 + 0.23 = 1.005 m² per metre. L is the clear length between column faces. A secondary beam is measured up to the side of the main beam it joins, and nothing is cut out of the main beam where it does (clause 6.1, as amended). Beams 1 m deep or more are a separate item (clause 5j).

A plinth beam cast on a PCC bed needs only its two sides: 2 × D × L. A 230 × 300 mm plinth beam takes 0.60 m² per metre, which is 0.18 m² for every running foot, the same figure the plinth beam cost guide works out. If the beam is cast in the air with no bed under it, add the bottom.

Lintels and chhajjas follow the same idea. A 230 × 150 mm lintel over a 1.0 m window, resting 150 mm on the wall at each end, has two sides of 1.30 × 0.15 m and a bottom only over the 1.0 m opening: 0.39 + 0.23 = 0.62 m². A chhajja, the sunshade over a window, is measured on its underside with its edges counted inside the same item (clause 5q). One that sticks out 600 mm, runs 1.3 m and thins from 100 mm to 75 mm comes to about 0.98 m².

How do you calculate shuttering area of a slab?

Measure the underside of each slab panel between the faces of the beams that carry it, and add the panels up. The top of a slab is never shuttered. For a room on a 3.60 × 4.20 m column grid with 230 mm wide beams, the clear panel is (3.60 − 0.23) × (4.20 − 0.23) = 3.37 × 3.97 = 13.38 m², or 144.0 sq ft.

Four rules decide what else goes in:

• Openings. Nothing is deducted for an opening of up to 0.4 m² (clause 6.4). A 600 × 600 mm duct cut-out is 0.36 m², so it stays in. A bigger opening comes off, and its edges are measured instead.
• Edges. Where a slab ends without an edge beam, its edge is measured in running metres, not square metres, when the slab is under 200 mm thick (clause 5m). Where there is an edge beam, the beam’s outer face already forms that edge.
• Thick slabs. A floor more than 200 mm thick is a separate item, with its thickness stated (clause 5b).
• Sloping roofs. A slab sloping up to 30° is shuttered on the underside only. Above 30° a top shutter may be used as well, but only the underside is measured (clause 5d).

Because only the underside counts, a slab always comes to 1 ÷ thickness square metres of shutter per cubic metre of slab concrete. When the shutter can safely come off is a different question, answered in shuttering removal time for a slab.

How do you calculate shuttering for a staircase?

A stair flight is shuttered on three surfaces: the sloping underside of the waist slab, the face of every riser, and each open side of the flight. The waist is the sloping slab that carries the steps; the riser is the height of one step. The landing is not part of the stair item. IS 1200 lists “staircases with sloping or stepped soffits, including risers and stringers, excluding landing” as one item (clause 5r), and the landing goes with the flat soffits.

Take the flight from the staircase concrete calculation guide: nine 175 mm risers, eight 250 mm treads, 1.0 m wide, with a 150 mm waist. Its inclined length is √(1.575² + 2.00²) = 2.55 m.

• Soffit: inclined length × width = 2.55 × 1.0 = 2.55 m².
• Risers: number of risers × riser height × width = 9 × 0.175 × 1.0 = 1.58 m². The ninth riser is the step up onto the landing, and it needs a board too.
• Each open side: inclined length × waist, plus the triangle of every step = 2.55 × 0.15 + 8 × ½ × 0.175 × 0.25 = about 0.56 m².

Table 4: Dog-legged staircase, two flights side by side

Four open sides assumes both flights are free on both sides, which is how a stair cast before the walls is built. Where a side sits against a finished wall, the wall is the mould and that side drops out. The landing is 150 mm thick, so any free edge of it goes in running metres under the slab edge rule.

Figure 1: The faces measured on a stair flight

Red is the sloping soffit, blue the riser faces, and green the open side of the flight, counted once for each side not against a wall. The grey landing is measured with the slabs, not with the stair.

What is the thumb rule for shuttering area per cubic metre of concrete?

There is no single figure for a building, but every member has its own, set by its shape. Divide a member’s shutter area by its concrete volume and the length cancels out. For a slab that leaves 1 ÷ thickness. For a column it leaves girth ÷ cross-section area. These ratios are a good check on a take-off: if a quantity sheet shows 20 m² of shutter for 1 m³ of 125 mm slab, something has gone wrong.

Table 5: Shuttering area per cubic metre of concrete, by member (our own arithmetic from the formulas above)

Two cautions. These figures check a quantity; they are never a way to price shuttering by the cubic metre, and the shuttering rate guide explains why a rate per m³ quietly carries someone else’s beam depths inside it. And the figure for a whole building depends on its mix of members. Slender frames with many columns sit high. Buildings with big footings and thick slabs sit low.

Worked example: shuttering area for a small house frame

Here is the whole sum for the RCC frame of a small single-storey house. Six columns of 230 × 300 mm stand on a grid of two 3.60 m bays one way and one 4.20 m bay the other, centre to centre. Each column sits on a 1.2 × 1.2 m box footing, 300 mm deep, whose top is 1.2 m below floor level. Plinth beams of 230 × 300 mm on a PCC bed tie the columns at floor level. The roof is a 125 mm slab on 230 × 450 mm beams, 3.0 m from floor to the top of the slab. For clause 2.7, the datum is the plinth, or floor, level.

Clear lengths come first, because every beam stops at a column face. Along the 3.60 m bays the clear length is 3.60 − 0.23 = 3.37 m, four spans in all. Along the 4.20 m bay it is 4.20 − 0.30 = 3.90 m, three spans. That is 25.18 m of beam on each level. On the roof, six of the seven spans are edge beams.

Table 6: Take-off for the house frame

Three things stand out. Above the plinth the frame carries 69.87 m² of shutter against 26.76 m² of clear floor under the slab, about 2.6 times; smaller rooms push that up, because beam and column faces grow faster than floor area. The slab is the biggest single line, yet beams and columns together come to more (43.11 m²). And the frame holds about 12.1 m³ of concrete, so the whole job works out near 8.4 m² of shutter per m³: about 6.5 below the plinth and 9.6 above it.

This frame has no stair, lintels or chhajjas. Add them as separate lines, worked the way the sections above show.

When the shutters are ready, the concrete has to arrive on time to fill them. Compare live concrete mixer models, from self-loading mixers such as the CONMAT CSLM 2800 and the Tarle SLM 2200 to transit mixers, and talk to a dealer before you fix the date of the pour.

How do you convert shuttering area to sq ft and plywood sheets?

Multiply square metres by 10.764 to get square feet, and divide by 10.764 to go back. The house frame above is 101.25 m², or about 1,090 sq ft, of exactly the same work. Do not mix up square feet of shutter face with square feet of built-up area, the unit of a house rate.

To turn area into sheets, divide by the area of one sheet. IS 4990:2011, the Indian Standard for plywood for concrete shuttering work, lists 2,400 × 1,200 mm as its largest standard board, which is 2.88 m². A board sold as 8 × 4 feet is 32 sq ft, about 2.97 m². So the 51.58 m² of roof beams and slab in the example needs at least 51.58 ÷ 2.88 = 18 boards of 2,400 × 1,200 mm if the whole deck is done in ply.

Treat that as the floor, not the order. The measured area is net: IS 1200 puts overlaps at corners inside the item (clause 3a) and adds nothing for offcuts, so the carpenter’s cutting plan decides the real count. Shutters are also reused, so you buy for one pour stage, not the whole house. IS 4990 lists boards from 4 mm to 40 mm thick; the thickness your slab needs is the engineer’s call, along with the props under it.

With the area fixed, the rest of the quantity sheet follows. The construction estimate format shows where each shuttering line sits in a bill of quantities, the bar bending schedule takes the steel off the same drawings, and cover block sizes set the gap between that steel and the shutter face. For a quick budget for the whole house, try the house construction cost calculator. More estimating topics are in the construction cost guides.

For the pour itself, compare concrete mixers and, for slabs above the first floor, concrete pump models, and speak to a dealer in your district.

The measurement rules on this page are from IS 1200 (Part 5):2013, Method of Measurement of Building and Civil Engineering Works, Part 5 Formwork, clauses 2.4, 2.5, 2.7, 3, 5, 6.1 and 6.4, with Amendment 1 of February 2020. Board sizes and thicknesses are from IS 4990:2011, Plywood for Concrete Shuttering Work, clauses 7.2 and 7.3. Every worked figure and the per-cubic-metre table are our own arithmetic on the sizes stated. Sources read in November 2026.

Prices, specifications and features are indicative, vary by variant, location and date, and should always be confirmed with the official OEM or authorised dealer before any purchase decision. DesiMachines is not liable for decisions taken on the basis of information that may have changed after publication. The member sizes in the examples are illustrations, not a design; your structural drawings decide every dimension.