Steel and TMT bar calculator
Estimate steel by element
Enter the concrete volume for that element — this gives a planning range, not an order quantity.
Estimated steel range
Always confirm against the structural drawing before ordering.
- Range0
- Low end0
- High end0
Calculate bar weight by diameter
Enter how many bars of each diameter, and the length of each bar — leave a row at 0 to skip it.
| Diameter | No. of bars | Length per bar (m) | Weight |
|---|---|---|---|
| 8 mm | — | ||
| 10 mm | — | ||
| 12 mm | — | ||
| 16 mm | — | ||
| 20 mm | — | ||
| 25 mm | — |
Steel required
- Total weight0
- Total (tonnes)0
- Estimated material cost₹0
Sample figures shown for illustration — pending verification against real Tirupati market rates before publishing as fact.
Standard bar weights per metre
Weight per metre = diameter² ÷ 162.28 (the standard IS formula for TMT bars). These are the figures every steel dealer works from:
| Diameter | Weight/metre |
|---|---|
| 8 mm | 0.395 kg/m |
| 10 mm | 0.617 kg/m |
| 12 mm | 0.888 kg/m |
| 16 mm | 1.58 kg/m |
| 20 mm | 2.47 kg/m |
| 25 mm | 3.86 kg/m |
Thumb-rule ranges by element
| Element | kg per m³ |
|---|---|
| Footing | 50–80 kg/m³ |
| Column | 160–200 kg/m³ |
| Beam | 160–200 kg/m³ |
| Slab | 80–110 kg/m³ |
| Lintel | 70–90 kg/m³ |
| Staircase | 110–140 kg/m³ |
| Retaining wall | 100–130 kg/m³ |
How this is calculated
The thumb-rule figures (kg of steel per cubic metre of concrete) come from typical Indian residential construction practice and are deliberately given as a range, never a single number — actual steel content depends on span, load, and the specific structural design, which only a structural engineer's drawing captures. A lightly loaded footing might sit at the bottom of its range; a long-span beam carrying a heavy upper floor could sit at the top, or even above it in an unusual design.
The bar-weight formula, by contrast, is exact: it's the standard relationship between a TMT bar's cross-sectional area and steel's density, used industry-wide to convert a bar's length into a weight for billing. Because weight scales with the square of the diameter, doubling a bar's diameter (say from 10 mm to 20 mm) doesn't double its weight — it roughly quadruples it, which is why structural drawings are precise about which diameter goes where rather than treating them as interchangeable.
When to use a thumb rule and when not to
Use the thumb-rule estimate only for early budgeting — deciding roughly how much a build will cost, or sanity-checking a contractor's quote. Once a structural engineer has issued a bar-bending schedule, switch entirely to the bar-weight calculator (or the schedule's own totals) for actual ordering. Ordering steel purely off a thumb-rule range, without an engineer's drawing, risks either an unsafe structure (under-ordering, if you build to the low end of the range but the design needed more) or significant wasted cost (over-ordering).
Frequently asked questions
How much steel is required per cubic metre of concrete for a slab?
Roughly 80–110 kg of steel per cubic metre of concrete for a typical residential slab, though the exact figure depends on the span and load — always confirm against the structural drawing.
How do I calculate the weight of a TMT bar?
Weight per metre = diameter² ÷ 162.28. Multiply that by the bar's length in metres, then by how many bars you have, to get the total weight.
How much does a 12mm TMT bar weigh per metre?
About 0.888 kg per metre. A standard 12-metre length bar weighs roughly 10.7 kg.
How much steel is needed for a column?
Roughly 160–200 kg of steel per cubic metre of concrete for a column — towards the higher end for heavily loaded columns, confirmed by the structural design.
What's the difference between the two calculators on this page?
The 'by element' thumb rule gives a rough planning range before you have drawings. The 'by bar weight' calculator gives an exact total once you know the actual bar diameters, counts and lengths — typically from a structural engineer's bar-bending schedule.
Building on your own land?
Building vs. buying — the real comparison
This calculator is for people building on land they already own. If you're still deciding between building yourself and buying a finished flat, this comparison covers the real costs and timelines of both.