Indian Tax Calc

function Get-TaxNewRegime {
  param([double]$Income)
  # FY 2025-26 new regime slabs (post Budget 2025)
  $slabs = @(
    @{UpTo=400000;  Rate=0},
    @{UpTo=800000;  Rate=0.05},
    @{UpTo=1200000; Rate=0.10},
    @{UpTo=1600000; Rate=0.15},
    @{UpTo=2000000; Rate=0.20},
    @{UpTo=2400000; Rate=0.25},
    @{UpTo=[double]::MaxValue; Rate=0.30}
  )
  $tax = 0; $prev = 0
  foreach ($slab in $slabs) {
    if ($Income -le $prev) { break }
    $taxable = [math]::Min($Income, $slab.UpTo) - $prev
    $tax += $taxable * $slab.Rate
    $prev = $slab.UpTo
  }
  # Rebate u/s 87A: nil tax if income <= 12,00,000
  if ($Income -le 1200000) { $tax = 0 }
  $cess = $tax * 0.04
  return [PSCustomObject]@{ Tax=$tax; Cess=$cess; Total=[math]::Round($tax+$cess,2) }
}

Get-TaxNewRegime -Income 1500000

function Get-TaxOldRegime {
  param([double]$Income, [double]$Deductions = 0)
  $taxableIncome = $Income - $Deductions
  $slabs = @(
    @{UpTo=250000;  Rate=0},
    @{UpTo=500000;  Rate=0.05},
    @{UpTo=1000000; Rate=0.20},
    @{UpTo=[double]::MaxValue; Rate=0.30}
  )
  $tax = 0; $prev = 0
  foreach ($slab in $slabs) {
    if ($taxableIncome -le $prev) { break }
    $taxable = [math]::Min($taxableIncome, $slab.UpTo) - $prev
    $tax += $taxable * $slab.Rate
    $prev = $slab.UpTo
  }
  if ($taxableIncome -le 500000) { $tax = [math]::Min($tax, 12500) }
  $cess = $tax * 0.04
  return [PSCustomObject]@{ TaxableIncome=$taxableIncome; Tax=$tax; Cess=$cess; Total=[math]::Round($tax+$cess,2) }
}

Get-TaxOldRegime -Income 1500000 -Deductions 150000  # 80C deduction

function Get-STCG {
  param([double]$BuyPrice, [double]$SellPrice, [int]$Qty)
  $gain = ($SellPrice - $BuyPrice) * $Qty
  $tax  = if ($gain -gt 0) { $gain * 0.20 } else { 0 }   # 20% STCG from FY25-26
  return [PSCustomObject]@{ Gain=$gain; STCGTax=[math]::Round($tax,2) }
}
Get-STCG -BuyPrice 500 -SellPrice 750 -Qty 100

function Get-LTCG {
  param([double]$BuyPrice, [double]$SellPrice, [int]$Qty)
  $gain   = ($SellPrice - $BuyPrice) * $Qty
  $exempt = 125000   # ₹1.25 lakh LTCG exemption per FY (FY25-26)
  $taxable = [math]::Max(0, $gain - $exempt)
  $tax    = $taxable * 0.125   # 12.5% LTCG from FY25-26
  return [PSCustomObject]@{ Gain=$gain; TaxableGain=$taxable; LTCGTax=[math]::Round($tax,2) }
}
Get-LTCG -BuyPrice 200 -SellPrice 400 -Qty 1000

# F&O profits/losses are added to regular income and taxed at slab rate
# No special rate — it's ordinary business income
function Get-FnOTax {
  param([double]$FnOProfit, [double]$OtherIncome = 0)
  $totalIncome = $FnOProfit + $OtherIncome
  $tax = Get-TaxNewRegime -Income $totalIncome
  return [PSCustomObject]@{
    FnOProfit    = $FnOProfit
    TotalIncome  = $totalIncome
    TaxLiability = $tax.Total
    Note         = "F&O taxed at slab rate; maintain books; ITR-3 required"
  }
}
Get-FnOTax -FnOProfit 200000 -OtherIncome 800000