I haven't found a calculator that depositors need to calculate the impact on their investment from early withdrawal penalties. So, here is a link to an Excel spreadsheet that you can use to calculate the impact of early withdrawal penalties
https://app.box.com/s/ocuposih32mz20kwh2o8p7qhj9yugrwe
It calculates the "Give-Up" Yield or the APY Needed to Reinvest the Net Amount after Early Withdrawal to Maintain the Original Value at Maturity. In other words, it tells you what yield you need to stay equal to the value of your current CD.
Let me know if you find this helpful. Also, if anyone has seen this or something equivalent somewhere else, please point me to it.
Seems like something CD owners should have been accessing long ago.