Rebar Weight Calculator

import math

def rebar_weight(diameter_mm, length_m, quantity=1, density_kg_m3=7850):
    """
    Calculate reinforcement steel (rebar) weight and properties.

    diameter_mm: Nominal rebar diameter in mm
    length_m: Single bar length in meters
    quantity: Total count of rebar pieces
    density_kg_m3: Steel density (standard 7850 kg/m³)
    """
    if diameter_mm <= 0 or length_m <= 0 or quantity <= 0 or density_kg_m3 <= 0:
        raise ValueError("All inputs must be strictly positive.")

    radius_m = (diameter_mm / 2.0) / 1000.0
    area_m2 = math.pi * (radius_m ** 2)
    
    unit_weight_kg_m = area_m2 * density_kg_m3
    total_length_m = length_m * quantity
    total_weight_kg = unit_weight_kg_m * total_length_m
    total_weight_ton = total_weight_kg / 1000.0

    return {
        "unit_weight_kg_m": round(unit_weight_kg_m, 3),
        "total_length_m": round(total_length_m, 2),
        "total_weight_kg": round(total_weight_kg, 2),
        "total_weight_ton": round(total_weight_ton, 3)
    }

# Example
res = rebar_weight(diameter_mm=16, length_m=12, quantity=100)
print(f"Unit Weight: {res['unit_weight_kg_m']} kg/m")
print(f"Total Weight: {res['total_weight_ton']} Metric Tons")

function [unit_weight, total_weight_ton] = rebar_weight(d_mm, L_m, Q, rho)
    % Rebar Weight Calculator
    % d_mm = Bar diameter (mm), L_m = Length (m), Q = Quantity, rho = Density (kg/m^3)
    if nargin < 4, rho = 7850; end
    if nargin < 3, Q = 1; end

    if d_mm <= 0 || L_m <= 0 || Q <= 0 || rho <= 0
        error('All parameters must be strictly positive.');
    end

    area_m2 = pi * ((d_mm / 2) / 1000)^2;
    unit_weight = area_m2 * rho;
    total_weight_ton = (unit_weight * L_m * Q) / 1000;
end

% Example
[w_unit, w_total] = rebar_weight(16, 12, 100);
fprintf('Unit Weight: %.3f kg/m\n', w_unit);
fprintf('Total Weight: %.3f Tons\n', w_total);