Calculation result
Submit the calculator to view weight, length, quantity, and allowance details.
| Formula | Choose a mode and enter valid values. |
|---|
No calculation has been completed.
Multi-rebar schedule
Build a bar schedule with mixed sizes, lengths, quantities, laps, hooks, and waste rates.
| Bar mark | Description | Size | Custom mm | Length each | Unit | Quantity | Lap each | Hook each | Waste % | Unit kg/m | Total length m | Total weight kg | Actions |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Schedule totals | 0.00 | 0.00 | |||||||||||
Add a row to begin the schedule.
Local calculation history
Formula used
Precise density formula: Weight = (π × d² ÷ 4) × length × density.
Metric shortcut: Unit weight ≈ d² ÷ 162 kilograms per metre.
Diameter uses metres in the precise formula. This calculator converts millimetres automatically.
How to use
- Select the required calculation mode.
- Choose a standard size or enter a custom diameter.
- Enter length, quantity, allowances, waste, and density.
- Submit the form and review every converted result.
- Use the schedule for several rebar groups.
- Copy, export, or print the completed calculation.
Example data
| Input | Example value | Purpose |
|---|---|---|
| Rebar size | 16 mm | Sets the theoretical cross-sectional area. |
| Length each | 12 m | Defines one straight bar before allowances. |
| Quantity | 25 | Builds the total scheduled length. |
| Lap each | 0.6 m | Adds connection overlap to every bar. |
| Hook each | 0.2 m | Adds bending or anchorage length. |
| Waste | 5% | Adds an estimating allowance. |
Metric rebar reference
| Diameter | Approximate kg/m | Approximate lb/ft |
|---|---|---|
| 6 mm | 0.222 | 0.149 |
| 8 mm | 0.395 | 0.265 |
| 10 mm | 0.617 | 0.415 |
| 12 mm | 0.889 | 0.597 |
| 16 mm | 1.580 | 1.062 |
| 20 mm | 2.469 | 1.659 |
| 25 mm | 3.858 | 2.592 |
| 28 mm | 4.840 | 3.252 |
| 32 mm | 6.321 | 4.248 |
| 36 mm | 8.000 | 5.376 |
| 40 mm | 9.877 | 6.637 |
US rebar reference
| US size | Diameter mm | Theoretical kg/m |
|---|---|---|
| #2 | 6.350 | 0.249 |
| #3 | 9.525 | 0.559 |
| #4 | 12.700 | 0.994 |
| #5 | 15.875 | 1.554 |
| #6 | 19.050 | 2.237 |
| #7 | 22.225 | 3.045 |
| #8 | 25.400 | 3.978 |
| #9 | 28.650 | 5.061 |
| #10 | 32.260 | 6.416 |
| #11 | 35.810 | 7.906 |
| #14 | 43.000 | 11.400 |
| #18 | 57.330 | 20.264 |
Frequently asked questions
How is rebar weight calculated?
Weight comes from steel volume and density. Diameter defines the circular cross-sectional area. Length then converts that area into total steel volume.
Why does actual rebar weight differ?
Manufacturing tolerances can change the final mass. Surface ribs also affect measured dimensions slightly. Confirm supplier data before final procurement decisions are made.
What density should I use?
Ordinary carbon steel commonly uses 7,850 kilograms per cubic metre. Special alloys may use another value. Enter certified material density when accurate purchasing depends upon it.
Does waste increase calculated length?
Yes, waste adds purchasing allowance after scheduled length. It covers cutting losses and practical site variation. Adjust the percentage using project standards and contractor experience.
Are laps and hooks included?
Both allowances are added to every selected bar. Their values use the chosen length unit. Enter zero whenever drawings already include those extra lengths.
Can I use US rebar sizes?
Yes, common US bar numbers appear in the selector. Their nominal diameters convert internally into millimetres. Review project specifications before substituting regional bar designations onsite.
What does unit weight mean?
Unit weight is mass for one metre of rebar. It depends on diameter and entered density. Larger diameters increase weight according to the diameter squared.
Can the calculator find bar quantity?
Yes, quantity mode divides available weight by one complete bar. It returns only whole usable bars. Remaining steel weight is also shown for planning purposes.
Is the result suitable for ordering?
The result supports estimating and preliminary quantity checks. Final orders need drawings and supplier confirmation. Always review lap rules, tolerances, stock lengths, and wastage.