Steel Bar Weight Chart — 8mm to 25mm (Per Metre, Per Foot, Per Bar)

Introduction

If you work in construction, you will look up steel bar weights hundreds of times in your career. Whether you are preparing a bar bending schedule, checking a delivery challan, or estimating project costs — you need to know the weight per metre for every common bar diameter.

This guide gives you the complete steel bar weight chart from 8mm to 25mm, explains the D²/162 formula so you actually understand where the numbers come from, and covers practical uses of each bar size on Indian construction sites.

The D²/162 Formula

Before the chart, understand the formula. If you remember just one thing from this article, remember this:

Weight per metre (kg/m) = D² / 162

Where D = diameter of the bar in millimetres.

Where Does 162 Come From?

The exact derivation:

• Cross-sectional area of a round bar = (pi/4) x D² mm²
• Volume per metre length = (pi/4) x D² x 1000 mm³
• Convert to cubic metres = (pi/4) x D² x 1000 / 10^9 cum
• Multiply by steel density = (pi/4) x D² x 1000 x 7850 / 10^9 kg
• Simplify = D² / 162.18

We round 162.18 to 162 for practical use. The error is less than 0.1%.

Quick Mental Math

For fast site calculations:

• 8mm bar: 8 x 8 / 162 = 64/162 = 0.395 kg/m
• 12mm bar: 12 x 12 / 162 = 144/162 = 0.889 kg/m
• 16mm bar: 16 x 16 / 162 = 256/162 = 1.580 kg/m

Once you practise this a few times, you can estimate steel weight in your head on site.

Complete Steel Bar Weight Chart

Here is the full reference chart for all standard TMT bar sizes used in Indian construction (as per IS 1786):

Weight Per Metre

Bar Diameter	Weight per Metre (kg/m)	Weight per Foot (kg/ft)	Weight per 12m Bar (kg)
8 mm	0.395	0.120	4.74
10 mm	0.617	0.188	7.40
12 mm	0.889	0.271	10.67
16 mm	1.580	0.482	18.96
20 mm	2.469	0.752	29.63
25 mm	3.858	1.176	46.30

Number of Bars per Tonne

This is useful when placing orders or cross-checking steel delivery:

Bar Diameter	Weight per 12m Bar	Bars per Tonne (approx.)
8 mm	4.74 kg	211 bars
10 mm	7.40 kg	135 bars
12 mm	10.67 kg	94 bars
16 mm	18.96 kg	53 bars
20 mm	29.63 kg	34 bars
25 mm	46.30 kg	22 bars

Weight Comparison per Running Metre

To visualise the difference between bar sizes, consider that:

• A 16mm bar is 4 times heavier than an 8mm bar (not 2 times)
• A 25mm bar weighs nearly 10 times more than an 8mm bar
• Doubling the diameter quadruples the weight, because weight is proportional to D²

This is why using the correct bar diameter matters so much for cost control.

Common Uses of Each Bar Size

8mm Bars

• Stirrups in beams and columns
• Distribution bars in slabs
• Tie bars in light structural members
• Ring bars in circular columns

8mm bars are the lightest and are almost never used as main reinforcement in structural members. Their primary role is providing shear resistance through stirrups and holding main bars in position.

10mm Bars

• Main bars in one-way slabs (for short spans up to 3m)
• Distribution bars in heavier slabs
• Stirrups in larger beams (where 8mm is insufficient)
• Light lintels and chajjas

10mm is a versatile size, commonly used in residential slabs designed for moderate loads.

12mm Bars

• Main bars in residential slabs (spans 3-5m)
• Main bars in lintels and sunshades
• Secondary reinforcement in beams
• Starter bars for columns

12mm is arguably the most commonly used bar size in Indian residential construction. Most ground-floor and first-floor slabs in houses use 12mm bars as primary reinforcement.

16mm Bars

• Main bars in beams (residential and small commercial)
• Column reinforcement (ground floor of 2-3 storey buildings)
• Main bars in heavier slabs (long spans, high loads)
• Foundation beams and grade beams

16mm marks the transition from light to medium structural use. Most residential beams in India use 16mm or a combination of 16mm and 12mm bars.

20mm Bars

• Main bars in heavy beams (commercial, multi-storey)
• Column reinforcement (multi-storey buildings, 3+ floors)
• Raft foundation reinforcement
• Retaining wall main bars

20mm bars are standard in multi-storey construction. They are heavier to handle on site and require more lap length, but provide significantly higher tensile capacity.

25mm Bars

• Heavy column reinforcement (high-rise, commercial)
• Deep beams and transfer girders
• Pile foundations and large footings
• Bridge and infrastructure work

25mm is the upper limit for most building construction. Beyond this, 28mm and 32mm bars are used mainly in infrastructure projects like bridges and flyovers.

Steel Prices in India (2026)

Current TMT bar prices vary by city and brand:

City	Fe500 Price (per kg)	Per Tonne
Mumbai	Rs 62-70	Rs 62,000-70,000
Delhi	Rs 58-65	Rs 58,000-65,000
Bangalore	Rs 60-68	Rs 60,000-68,000
Pune	Rs 60-66	Rs 60,000-66,000

Note: Prices fluctuate monthly based on iron ore costs and demand. Always get a fresh quote from your supplier before placing orders.

Cost per 12m Bar

Diameter	Weight (kg)	Cost at Rs 65/kg
8 mm	4.74	Rs 308
10 mm	7.40	Rs 481
12 mm	10.67	Rs 693
16 mm	18.96	Rs 1,232
20 mm	29.63	Rs 1,926
25 mm	46.30	Rs 3,010

How to Verify Steel Delivery on Site

When steel arrives at your site, you should verify the quantity. Here is a practical method:

1. Count the bars of each diameter
2. Multiply count by weight per bar from the chart above
3. Compare with the challan weight
4. Tolerance: IS 1786 allows +/- 5% variation in weight for individual bars. For a bundle, the variation should be within +/- 2.5%

Example: You ordered 1 tonne of 12mm bars. You should receive approximately 94 bars (each 12m long). If you count only 88 bars, the actual weight is 88 x 10.67 = 939 kg — you are short by 61 kg.

Lap Length and Extra Steel

When estimating total steel for a project, do not forget to add:

• Lap length: 40d to 50d for tension bars (where d = bar diameter). For 16mm bar, lap = 40 x 16 = 640mm minimum
• Cranked bar extra: 0.42d for each crank
• Hook allowance: 9d for each standard hook
• Wastage: 3-5% of total steel for cutting and bending waste

These additions can increase your steel requirement by 8-12% over the theoretical bar lengths.

Use Yojo Calculators for Accurate Estimates

Instead of calculating steel weight manually every time, use the Yojo Steel Rebar Calculator. Enter the bar diameter and total length, and get instant weight and cost calculations.

For complete reinforcement estimation including lap lengths and hooks, the calculator handles all the additions automatically.

Use our free calculator to get accurate steel quantities for your next project.

Summary

The steel bar weight chart is one of the most fundamental references in construction. Here are the key numbers every contractor should memorise:

• 8mm = 0.395 kg/m
• 10mm = 0.617 kg/m
• 12mm = 0.889 kg/m
• 16mm = 1.580 kg/m
• 20mm = 2.469 kg/m
• 25mm = 3.858 kg/m

And the formula behind all of them: D²/162. With this single formula, you can calculate the weight of any steel bar diameter, anywhere, without needing a chart at all.