Record with static helper

Program.cs

using System;

var weight = 200;
WeightMeasurement measurement = new(DateTime.Now, weight)
{
    Pounds = WeightMeasurement.GetPounds(weight)
};

Console.WriteLine(measurement);

public record WeightMeasurement(DateTime Date, double Kilograms)
{
    public double Pounds {get; init;}

    public static double GetPounds(double kilograms) => kilograms * 2.20462262;
}

weight.csproj

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net5.0</TargetFramework>
    <Nullable>Enable</Nullable>
  </PropertyGroup>

</Project>