Make a bar bending schedule (BBS) for a rectangular RCC footing: an isolated footing, a combined footing or a small raft. Enter the footing size, the depth, the cover and the bars from your drawing, and the calculator gives the number of bars and the cutting length in each direction, the steel weight by diameter and the concrete volume. Part of our BBS calculators.
How to use the footing BBS calculator
- Enter the footing length (X) and width (Y), or tap a common size, then the footing depth.
- Choose the clear cover: 50 mm or 75 mm.
- Enter the bottom bars in each direction: the diameter and the spacing.
- Tick Top mesh only if your drawing shows bars at the top as well, as in many combined footings and rafts.
- Choose how the bars end: bent up to the top cover, a fixed L-leg, or straight.
- Enter the number of identical footings and any wastage, then download the schedule as CSV, print it or share a link.
Footing BBS Calculator
Bar bending schedule for a rectangular RCC footing: bottom mesh, optional top mesh, cutting lengths and steel
Column and laps
Bar bending schedule
Steel by diameter
Checks
Educational BBS for quantity estimate. Footing size, depth, bar sizes, spacing, cover and end details must come from the structural drawing; this is not foundation design or a detailing sign-off. Rules follow common Indian practice as used in the source sheets, with the corrections noted on the page.
Formulas used
| Item | Formula |
|---|---|
| Number of bars along X | (Y side − 2c) ÷ spacing, rounded up, + 1 |
| Number of bars along Y | (X side − 2c) ÷ spacing, rounded up, + 1 |
| Cutting length | Side − 2c + 2 × leg − 2 × 2φ (two 90° bends) |
| Leg, bent up to the top | Footing depth − 2c |
| Straight bars | Side − 2c, no bend deduction |
| Laps | One lap of 50φ for each extra 12 m stock bar, only on bars longer than 12 m |
| Weight | φ² ÷ 162 kg per metre × total length |
| Concrete | Length × width × depth (a rectangular pad) |
φ is the bar diameter and c the clear cover, in mm. A sloped footing uses the same mesh; its concrete volume will be less than the figure shown.
Worked example
A 2000 × 1500 mm footing, 450 mm deep, with 50 mm cover and 12 mm bars at 150 mm both ways, bent up to the top cover:
- Leg: 450 − 2 × 50 = 350 mm.
- Bars along X: (1500 − 100) ÷ 150 = 9.33, rounded up to 10, + 1 = 11 bars. Cutting length 2000 − 100 + 700 − 48 = 2552 mm.
- Bars along Y: (2000 − 100) ÷ 150 = 12.67, rounded up to 13, + 1 = 14 bars. Cutting length 1500 − 100 + 700 − 48 = 2052 mm.
- Steel: 28.07 m + 28.73 m = 56.80 m of 12 mm bar at 0.889 kg/m = 50.49 kg.
With 150 mm legs instead, the same footing needs 11 bars of 2152 mm and 14 bars of 1652 mm, or 41.60 kg, which is the result in the site BBS sheet this tool was checked against.
Frequently asked questions
How is the cutting length of footing bars calculated?
Cutting length = footing side − 2 × cover + the two end legs − 2 × 2φ for the two 90° bends. For a 2000 mm footing with 50 mm cover, 12 mm bars and 150 mm legs this is 2000 − 100 + 300 − 48 = 2152 mm.
How many bars are needed in a footing?
Bars running along one side are spread across the other side. Number of bars = (other side − 2 × cover) ÷ spacing, rounded up, + 1. For bars at 150 mm across a 1500 mm side with 50 mm cover: 1400 ÷ 150 = 9.33, rounded up to 10, + 1 = 11 bars.
What cover is used for footing reinforcement?
IS 456 asks for at least 50 mm nominal cover to footing reinforcement. Many drawings use 50 mm, and 75 mm where the footing is cast directly against earth or the soil is aggressive. Follow your drawing.
Why are footing bars bent up at the ends?
The bottom bars of a footing carry tension and need anchorage near the edges, so they are usually given L-bends at both ends. Drawings either bend them up to the top cover or give a fixed leg such as 150 or 300 mm.
When does a footing need top reinforcement?
Isolated footings under a single column usually need only a bottom mesh. Combined footings, rafts and footings with uplift or large moments often have a top mesh as well, held up on chairs. Use the top mesh option only if your drawing shows it.
Are column starter bars part of the footing BBS?
They are often scheduled with the column, because the first column bar starts with an L-leg resting on the footing mesh. Our column BBS calculator includes that length; this footing calculator covers the footing mesh only.
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Disclaimer: Online educational publication only. Not a substitute for structural design or detailing by a licensed engineer. Full disclaimer · contact@speakarch.com
Last updated: 8 November 2026