So I wanted to start to make some conversions while still working. I Assume that is fine and just pay the taxes like usual.
How are the taxes handled? Do they take out of the conversion - (convert 10k and they take 2k and convert 8k? or convert 10k and take another 2.5k out of account?) or can you pay with another method - (checking transfer or credit card?) or does it wait until you file taxes with IRS, and if so do you need to pay extimated taxes at the quarterly interval? Or can you up additional withholding at your W2 job to cover the expected taxes?
Can I transfer shares directly between rollover IRA and roth IRA at vanguard, rather than just cash? There is a convient "convert to roth" button, but I am afraid to click it lest the entire account atomatically convert and I have mega taxes at higher tax brackets as a result.
Is anyone experienced with this button and can tell me what is behid it before I click it?
Answering some of the unanswered questions.
Yes, converting while working is fine. Conversions will add to ordinary income, and job income plus conversions plus whatever other income could push you into a higher bracket; you're probably aware of that effect.
Vanguard doesn't withhold taxes (either state or federal) from Roth conversions if you use the website. You *might* be able to withhold if you call in, but as the other poster mentioned, this is a bad idea if you are under 59.5. Increasing withholding or estimated taxes are probably easier.
You pay the taxes on the conversion with your taxes. Vanguard will send you a 1099-R in January-ish with the total amount of Roth conversions. If the conversion is large enough and you don't pay enough via either withholding and/or estimated taxes, then you may owe an underpayment penalty.
Yes, you can convert shares in-kind at Vanguard. The taxable amount will be the value of the shares as of the date of the transfer. If you initiate a web transfer, the transaction will occur at the next close of the market.
The button does not convert the entire account without any confirmations ;-) It asks you how much you want to convert, what assets you want to convert, etc. There are some confirmation things about taxes which I forget what they are because I never choose them, and then there is a very obvious "Yes, I want to convert 3.014 shares of VTSAX from my traditional IRA to my Roth IRA today and I understand I probably will owe some income taxes on the conversion" confirmation screen.