Yes, you can convert a 401(k) to a Roth IRA. Typically, you do this after you leave your work, but if your plan permits it, you may also do it while you're still employed. Since Roth IRAs are financed with after-tax funds, the conversion is taxable, meaning you will be responsible for paying income tax on the converted amount. Qualified withdrawals in retirement are tax-free after conversion. It's wise to review your plan's regulations and think about discussing the tax implications with a financial counsellor.