Steel Calculator
Work out TMT steel for your slabs, beams, columns and footings, bar by bar, or from the built-up area. Get the kg and tonnes, a diameter-wise order list with 12 m bar counts, binding wire and the cost.
1Breakdown
Where the steel goes
Steel for each item in your list, and how it splits across bar sizes.
| Item | Basis | Steel kg | 8 mm | 10 mm | 12 mm | 16 mm |
|---|---|---|---|---|---|---|
| RCC slab | 8.71 cum at 1.0% | 684 | 205 | 479 | — | — |
| RCC beams | 3.47 cum at 2.0% | 545 | 109 | — | 163 | 272 |
| RCC columns | 2.52 cum at 2.5% | 495 | 99 | — | 149 | 248 |
| Footings | 8.03 cum at 0.8% | 504 | — | 202 | 302 | — |
| Lintels, chajjas | 0.84 cum at 1.0% | 66 | 26 | 40 | — | — |
| Staircase | 0.78 cum at 1.2% | 74 | 15 | 29 | 29 | — |
| Total with wastage | 2,438 | 468 | 772 | 663 | 536 |
2Reference
Bar weight table
Weight per metre = D² ÷ 162. Handy for checking a dealer's weighment or a bar bending schedule.
| Bar size | kg per metre | kg per 12 m bar | 12 m bars per tonne | Typical use |
|---|---|---|---|---|
| 6 mm | 0.222 | 2.67 | 375 | Rings in light work |
| 8 mm | 0.395 | 4.74 | 211 | Stirrups, ties, slab bars |
| 10 mm | 0.617 | 7.41 | 135 | Slab and footing bars |
| 12 mm | 0.889 | 10.67 | 94 | Beams, columns, footings |
| 16 mm | 1.580 | 18.96 | 53 | Main bars of beams and columns |
| 20 mm | 2.469 | 29.63 | 34 | Heavier beams and columns |
| 25 mm | 3.858 | 46.30 | 22 | Large columns and foundations |
| 32 mm | 6.321 | 75.85 | 13 | Very heavy members |
3Grades
Fe 415, Fe 500, Fe 500D or Fe 550D: which TMT to buy?
The number is the minimum yield strength in N/mm². A D after it means extra ductility: the bar stretches more before it breaks, which helps a building ride out an earthquake.
Fe 415
415 N/mm²Use for: small works and older designs that call for it; bends easily.
Watch: less stocked now; needs more steel than Fe 500 for the same load.
Fe 500
500 N/mm²Use for: most houses and small buildings; the common choice at dealers.
Watch: buy from brands that give a mill test certificate.
Fe 500D
500 N/mm², higher ductilityUse for: buildings in seismic zones III to V and frames where the engineer asks for ductile detailing.
Watch: costs slightly more than Fe 500.
Fe 550D
550 N/mm², higher ductilityUse for: taller buildings and heavy structures where design uses the higher strength.
Watch: only saves steel if the design is done for Fe 550.
Follow the structural drawings. Bar sizes, spacing, laps and grade come from your engineer's design. Do not replace a bar with a thinner one of a higher grade unless the engineer approves it.
4Method
How the quantities are worked out
Three ways, from quick to exact.
- Typical steel shares. Slabs about 1% of concrete volume, beams 2%, columns 2.5%, footings 0.8%, lintels 1% and stairs 1.2%.
- Typical bar sizes. Slabs 8 and 10 mm; beams and columns 12 and 16 mm with 8 mm stirrups; footings 10 and 12 mm.
- Bar by bar is the most exact. Take cut lengths and numbers from the bar bending schedule.
5Scope
What this calculator does and does not do
Knowing the limits helps you add the right margin before you place an order.
✓It does
- Estimate TMT steel by member, by bar or from built-up area
- Split steel into bar sizes and count 12 m bars
- Add wastage and binding wire
- Price steel, wire, cutting and bending
- Give an order list, CSV, shareable link and print
✕It does not
- Design reinforcement or check a structure
- Make a bar bending schedule
- Cover structural steel sections such as beams, channels or angles
- Include cover blocks, couplers or transport
- Know your local prices; change the rates to match your dealer
6FAQ
Questions
What is the formula for the weight of a steel bar?
Weight in kg per metre = D² ÷ 162, where D is the bar diameter in mm. It comes from the steel density of 7,850 kg per cum. A 12 mm bar weighs 144 ÷ 162 = 0.889 kg per metre, or about 10.7 kg for a 12 m length.
How much steel is needed per square foot of a house?
A common thumb rule for an RCC framed house is about 3.5 to 4.5 kg per sq.ft. of built-up area, including footings, columns, beams, slabs and stairs. The From built-up area tab uses 4.0 kg for a framed house. Structural drawings and a bar bending schedule give the real figure.
How much steel is used per cubic metre of concrete?
As a share of concrete volume, slabs often carry about 1%, beams about 2%, columns 2 to 2.5% and footings about 0.8%. At 7,850 kg per cum of steel, 1% is about 78.5 kg per cum. The By members tab uses these and lets you change the percentage for each row.
How many 12 m bars make one tonne?
About 208 bars of 10 mm, 94 bars of 12 mm, 53 bars of 16 mm and 34 bars of 20 mm. The bar weight table on this page lists every common size.
What do Fe 415, Fe 500, Fe 500D and Fe 550D mean?
Fe is iron and the number is the minimum yield strength in N/mm². Fe 500 is the most common grade for houses. The D grades have better ductility, which matters in earthquake zones. Use the grade your structural engineer specifies; a higher grade is not a reason to cut bars on site.
How much binding wire is needed?
Usually about 8 to 12 kg of binding wire per tonne of reinforcement. The calculator uses 10 kg per tonne; change it if your site uses more.
Why add wastage for steel?
Bars come in 12 m lengths and are cut to size, so short end pieces and laps are lost. About 3 to 5% is common; bar bending schedules that plan cuts carefully can reduce it.
Is my data stored?
No. The calculator runs in your browser and loads no third-party scripts. Inputs leave the page only if you copy the link, share on WhatsApp or download the list.
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