There is no annual dollar limit on the amount you can roll over from a 401(k) to a Roth IRA.
If you roll over pre-tax money from a traditional 401(k) to a Roth IRA, the entire amount of the rollover is considered a taxable event. You must include the converted amount in your gross income for the year and pay ordinary income tax on it. You must complete the rollover within 60 days of receiving the distribution unless it’s a direct rollover.
If you roll over funds from a Roth 401(k) to a Roth IRA, it's a tax-free event as the money was already taxed.
Large rollovers in a single year can push you into a higher tax bracket. Many people choose to spread rollovers over multiple years to manage the tax impact.
https://www.irs.gov/retirement-plans/plan-participant-employee/rollovers-of-retirement-plan-and-ira-distributions This IRS link has valuable information about rollovers.
@mezarturo Thanks for the question.