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Rebar Weight Calculator

lb/ft × feet. Free online Rebar Weight Calculator. Calculate rebar weight online — fast, accurate, mobile-friendly, no signup needed.

Weight (lb)
13.344

Derivation

  1. ├── 01Givensize = 4, ft = 20
  2. ├── 02Formulae.ft × (t² × .0417)
  3. ├── 03Substitutee.20 × (t² × .0417)
  4. └── 04Compute Weight (lb)13.344
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§01What is

Understanding the Rebar Weight Calculator

The Rebar Weight Calculator computes Weight (lb) from 2 inputs: rebar # (3-11), length (ft). lb/ft × feet.

On a construction site, estimates that come in 10% off add up to six-figure overruns. Running the quantities with a calculator instead of a rule-of-thumb gets you closer to the truth with zero extra effort. The Rebar Weight Calculator sits in that toolkit — it lb/ft × feet. Enter your numbers above and the result updates instantly; every step of the math is shown in the Derivation panel so you can see exactly how the answer was reached.

§02The Formula

How it’s calculated

e.ft × (t² × .0417)

Where

size
Rebar # (3-11)
ft
Length (ft)
§03Practical Example

Step-by-step walkthrough

Scenario

Apply the formula to a realistic set of inputs: Rebar # (3-11) = 4, Length (ft) = 20.

  1. 01Start by noting the input — Rebar # (3-11): 4.
  2. 02Start by noting the input — Length (ft): 20.
  3. 03Substitute these values into the formula: e.ft × (t² × .0417)
  4. 04Compute Weight (lb): the calculator returns 13.344.
  5. 05Cross-check the answer by opening the Derivation panel above — every line of math is shown so you can follow the computation end-to-end.
§04Variants

Common Rebar Weight Problems

The formula gets rearranged depending on which variable you need. Here are the patterns you’ll run into in the real world — find the one that matches your problem and follow the worked steps.

01 · PATTERN

Rebar # (3-11) halved

size = 2 (from 4)

Keep every other input at its default and halve the rebar # (3-11). See how weight (lb) responds.

  1. 01New Rebar # (3-11): 2
  2. 02Baseline Weight (lb): 13.344
  3. 03New Weight (lb): 3.336
  4. 04Weight (lb) decreases by 75% → use this sensitivity to plan for real-world variation.
02 · PATTERN

Rebar # (3-11) doubled

size = 8 (from 4)

Keep every other input at its default and double the rebar # (3-11). See how weight (lb) responds.

  1. 01New Rebar # (3-11): 8
  2. 02Baseline Weight (lb): 13.344
  3. 03New Weight (lb): 53.376
  4. 04Weight (lb) increases by 300% → use this sensitivity to plan for real-world variation.
03 · PATTERN

Length (ft) halved

ft = 10 (from 20)

Keep every other input at its default and halve the length (ft). See how weight (lb) responds.

  1. 01New Length (ft): 10
  2. 02Baseline Weight (lb): 13.344
  3. 03New Weight (lb): 6.672
  4. 04Weight (lb) decreases by 50% → use this sensitivity to plan for real-world variation.
04 · PATTERN

Length (ft) doubled

ft = 40 (from 20)

Keep every other input at its default and double the length (ft). See how weight (lb) responds.

  1. 01New Length (ft): 40
  2. 02Baseline Weight (lb): 13.344
  3. 03New Weight (lb): 26.688
  4. 04Weight (lb) increases by 100% → use this sensitivity to plan for real-world variation.
§05FAQ

Frequently asked questions

Yes. The calculator implements the standard formula as documented and returns exact floating-point results. No approximations are used unless noted in the formula.
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