this is a very practical question I had to figure out the hard way so I'm writing it down.
my promo was approved in October. my paycheck in November was exactly the same as October. my December paycheck finally had the new base. I panicked about two months worth of pay before I understood why.
here's the typical sequence, based on what I've seen at two mid-size tech companies and heard from people at larger ones:
approval to paycheck timeline: committee approves your promo your manager sends you a congratulations message and may give you a general range HR generates a formal offer letter update, usually 1-3 weeks after committee finishes you receive and sign the letter the signed letter kicks off a payroll change request payroll processes changes on a cut-off date (usually 2 weeks before the pay date) if you miss the cut-off, it lands the NEXT pay cycle
so a promo approved late in the month can take 6-8 weeks to appear in actual take-home, even if you signed the letter in week 2.
the equity part is slower:
if your promo comes with a new RSU grant, that's on a completely different timeline. grant approval goes through a board committee (or a delegated committee). this can take another 4-8 weeks on top of the payroll change. the grant start date is usually your promo effective date but you won't see it in your equity account until the admin is done.
what to actually do:
ask your HR contact or your manager: "what's the effective date of the promotion and when should I expect to see the base change reflected?" get both answers in writing, not in a meeting. if a pay cycle passes without the change, follow up immediately with the effective date in hand.
you are also very likely owed back pay from the effective date if payroll was slow. most companies do this automatically but it can take one more cycle to see it. check your paystub line items.