Hey friend, imagine you’re standing on site and the contractor asks, “How many tons of steel do we need for this slab?”
If you guess wrong, you either waste lakhs or the structure becomes weak.
Today I’ll show you exactly how to calculate the weight of TMT bars in less than 60 seconds – manually or with phone – so you never get it wrong again.
I’ve personally checked thousands of tons on sites across Maharashtra, Rajasthan and Telangana for Sai Sevak Traders, so everything here comes from real experience, not just textbooks.
Why Does TMT Bar Weight Even Matter?
Steel is usually 12-18% of your total construction cost.
One small mistake in calculation can cost you ₹50,000 to ₹3 lakh extra on a normal house project.
Plus, if you put less steel than the drawing says, the building becomes unsafe.
If you put extra, you just burned money.
So let’s get this right – every single time.
The Magic Formula Everyone Uses in India
You’ve probably heard people say “D square by 162”.
Here’s what it actually means:
Weight in kg = (D × D) ÷ 162 × Length in meter
D = diameter of the bar in mm
Length = normally 12 meter (full rod)
That’s it. No rocket science.
Where Does “162” Come From? (The 30-Second Science)
Steel density = 7850 kg/m³ (fixed for all normal TMT)
Area of circle = πD²/4
When you do the full math and simplify, the number becomes exactly 162.162…
We round it to 162 for daily use.
That’s why the formula works perfectly on site.
TMT Bar Weight Chart 2026 (Per Meter & Per Rod) – Updated
| Diameter (mm) | Weight Per Meter (kg) | Weight of 1 Full Rod (12 m) | Approx. Rods in 1 Ton |
| 8 mm | 0.395 kg | 4.74 kg | 211 rods |
| 10 mm | 0.617 kg | 7.40 kg | 135 rods |
| 12 mm | 0.888 kg | 10.66 kg | 94 rods |
| 16 mm | 1.580 kg | 18.96 kg | 53 rods |
| 20 mm | 2.470 kg | 29.64 kg | 34 rods |
| 25 mm | 3.855 kg | 46.26 kg | 22 rods |
| 32 mm | 6.310 kg | 75.72 kg | 13 rods |
Bookmark this table – labourers and engineers use it every day.
Step-by-Step: How to Calculate Weight of TMT Bars Manually
Let’s do a real site example together.
Question:
You need 150 pieces of 16 mm TMT for a column. How many tons to order?
Step 1 → One 16 mm rod (12 m) = 18.96 kg
Step 2 → 150 rods × 18.96 kg = 2844 kg
Step 3 → 2844 ÷ 1000 = 2.844 tons
Order 3 tons (always round up a little for cutting wastage).
Takes 15 seconds once you remember the per-meter weight.
Quick Shortcut for Site (Even Faster)
Just remember this line:
“Weight per meter = D × D ÷ 162”
Examples:
12 × 12 ÷ 162 = 0.888 kg/m
20 × 20 ÷ 162 = 2.469 kg/m
25 × 25 ÷ 162 = 3.858 kg/m
That’s it. No calculator needed after two days of practice.
How to Convert Running Meter into Kg (Most Asked Question)
Many times drawing gives total steel in running meter (RMT).
Formula:
Total weight = Running meter × weight per meter
Example:
Drawing says 8 mm stirrups = 1200 running meter
Weight = 1200 × 0.395 = 474 kg → almost half ton
What About Cutting, Bending and Lapping?
Real life is not perfect 12-meter rods.
→ Cutting wastage: 2–3%
→ Lapping (overlap): extra 40D to 50D length per joint
→ Hooks & bends: add 10–15 cm per bend
Rule of thumb used by contractors:
Add 6–8% extra on total calculated weight.
So if calculation shows 10 tons → order 10.7–10.8 tons.
TMT Bar Weight Calculator (Free & Instant)
Want zero effort?
Use this simple calculator:
Diameter (mm) × Diameter × Length (m) ÷ 162 = Weight (kg)
Or just WhatsApp your quantity list to Sai Sevak Traders – we send you exact weight and current rate in 2 minutes.
Grade-wise Weight Difference (Fe415 vs Fe500 vs Fe550 vs Fe600)
Good news: All normal grades use the same density 7850 kg/m³.
So Fe500, Fe550D, Fe600 – weight remains exactly the same for same diameter.
Only strength changes, not weight.
Common Mistakes That Cost Lakhs
- Using wrong diameter (12 mm vs 12.5 mm confusion)
- Forgetting lapping length in beams/columns
- Using CTD bars formula on TMT (old formula gives wrong result)
- Not adding wastage percentage
Avoid these and you save money every project.
Quick FAQs – Asked Daily on Site
Q: How much does one bundle of 12 mm weigh?
A: Normally 5 rods = 53–55 kg (depends on brand tolerance)
Q: How many 10 mm rods in 1 ton?
A: 135 rods (easy to remember)
Q: Is there any difference in weight between brands?
A: ±2.5% tolerance allowed as per IS 1786:2008. Good brands stay within ±1%.
Q: Can I calculate weight from mobile?
A: Yes. Just type in Google “10mm TMT weight” – first result shows answer instantly because of articles like this!
Final Words From Experience
I’ve seen projects delayed for weeks because someone ordered 2 tons less steel.
I’ve also seen clients pay ₹1.8 lakh extra because they ordered too much.
When you know how to calculate the weight of TMT bars correctly, you control cost, timeline and safety – all three.
Need today’s rate or exact quantity calculation for your project?
Just drop a WhatsApp message to Sai Sevak Traders. We reply with weight + rate + transport cost in minutes – no obligation.
Stay safe, build strong!
See you on the next site. You can also check out the guide on Mild Steel Square Bars Weight Calculation.