Calculate ROIC with values from Alpha Vantage

I am attempting to calculate Return on Invested Capital using Alpha Vantage API. Can anyone help me validate the formulas below?

Other sources

I am not sure I get the proper result, as I can’t even find 2 stock analysis websites to agree on the values.

Formula

ROIC = Net Operating Profit after Tax / (Total equity + total Interest Bearing Debt)

1. Calculate NOPAT (calculate tax rate and multiply with operating income)
2. Calculate Invested Capital
3. Calculate ROIC

Alpha Vantage response attributes

Get balance sheet (from alpha vantage). I got "totalShareholderEquity" and "currentDebt" from here.

Get income statement. I calculated NOPAT = "operatingIncome" * (1 – "incomeTaxExpense" / "incomeBeforeTax")

1. ROIC = Net Operating Profit after Tax / (Total equity + total Interest Bearing Debt)

2. NOPAT = operatingIncome * (1 – incomeTaxExpense / incomeBeforeTax)

3. NOPAT = 21872000 * (1 – 3846000 / 25256000)

4. NOPAT = 18541318

5. ROIC = NOPAT / (totalShareholderEquity – currentDebt)

6. ROIC = 18541318 / (236327000 + 0)

7. ROIC = 7.84%

Help

So how far are my calculations from the reality? I tried different formulas found around the web, but given my lack of financial experience, I can’t match them perfectly on the values I get from Alpha Vantage.

If you would like/can look over the code, I posted a corresponding question on StackOverflow