How to Convert Pounds to Kilograms and Vice Versa in Batch Script

@echo off
setlocal enabledelayedexpansion

:menu
cls
echo ============================
echo      WEIGHT CONVERTER
echo ============================
echo 1. Pounds (lbs^) to Kilograms (kg^)
echo 2. Kilograms (kg^) to Pounds (lbs^)
echo 3. Exit
echo.
set "choice="
set /p "choice=Select (1-3): "

if "%choice%"=="1" goto :lbs2kg
if "%choice%"=="2" goto :kg2lbs
if "%choice%"=="3" exit /b
goto :menu

:lbs2kg
set "input="
set /p "input=Enter lbs: "
if not defined input goto :menu

:: Call math function: %1=value, %2=multiplier(scaled by 1000), %3=unit
call :convert "%input%" 454 "kg"
pause
goto :menu

:kg2lbs
set "input="
set /p "input=Enter kg: "
if not defined input goto :menu

:: Call math function: %1=value, %2=multiplier(scaled by 1000), %3=unit
call :convert "%input%" 2205 "lbs"
pause
goto :menu

:convert
set "val=%~1"
set "mult=%~2"
set "unit=%~3"

:: Normalize: Ensure leading zero for values like .5
if "!val:~0,1!"=="." set "val=0!val!"

:: Split into integer and decimal
set "int=" & set "dec="
for /f "tokens=1,2 delims=." %%A in ("!val!") do (
    set "int=%%A"
    set "dec=%%B00"
)
if not defined dec (
    :: This handles inputs like "5" or "5."
    for /f "delims=." %%A in ("!val!") do set "int=%%A"
    set "dec=00"
)
set "dec=!dec:~0,2!"

:: Strip leading zeros from integer part to avoid the Octal Trap (e.g. 08, 09)
:strip_loop
if "!int:~0,1!"=="0" if "!int!" neq "0" (
    set "int=!int:~1!"
    goto :strip_loop
)

:: Combine to a single scaled integer (Input * 100)
set /a "scaled=int * 100 + 1!dec! - 100" 2>nul

:: Sanity check for non-numeric or overflow
if !errorlevel! neq 0 (
    echo [ERROR] Invalid numeric input.
    exit /b
)

:: Perform conversion (Scaled by 100000)
set /a "result=scaled * mult" 2>nul
if !errorlevel! neq 0 (
    echo [ERROR] Input value is too large for processing.
    exit /b
)

set /a "whole=result / 100000"
set /a "frac=(result %% 100000) / 1000"
if !frac! lss 10 set "frac=0!frac!"

echo.
echo !val! is approximately !whole!.!frac! !unit!.
exit /b

@echo off
setlocal enabledelayedexpansion

set /p "lbs=Enter Pounds (lbs): "
if not defined lbs exit /b

:: Perform conversion using PowerShell (safe and accurate for decimals)
for /f "usebackq" %%R in (`
    powershell -NoProfile -Command ^
    "$v = ($env:lbs -replace ',', '.') -as [double]; if ($v -ne $null) { [math]::Round($v * 0.453592, 2) } else { exit 1 }"
`) do (
    set "kg=%%R"
)

:: Check if PowerShell exit code indicated failure
if %errorlevel% neq 0 (
    echo [ERROR] "!lbs!" is not a valid number.
    pause
    exit /b 1
)

echo !lbs! lbs is approximately !kg! kg.
pause