Payroll processing time is usually quoted as the length of the pay run, which is the smallest part of it. The timeline that matters runs from the cut off for changes to the money arriving, and it is set by bank lead times and your own approval chain rather than by how fast the software calculates.
The parts of the timeline
A cut off for hours and changes, a preparation and checking step, an approval, then submission to the bank, which settles on its own schedule. For most employers the calculation itself is minutes and the bank lead time is the binding constraint, which is why a faster product rarely shortens the overall cycle by much.
Work backwards from pay day
Fix the bank submission date first, then the approval, then the cut off, and publish the cut off to everybody who submits hours. Most late payroll is caused by a change arriving after the cut off and somebody agreeing to squeeze it in, which compresses the checking step that exists to catch errors.
Corrections after the cut off
They should be paid as a labelled adjustment in the next period rather than quietly folded in, and that rule should be written down before it is needed. Where a correction genuinely cannot wait, know what an off cycle payment costs and who may authorise one, because deciding that under pressure is how mistakes enter.
Questions people ask about how long does it take for payroll to process
Can payroll be run the same day?
The calculation can. Getting money to people the same day usually requires a faster payment method at additional cost.
What is a typical cut off?
A few working days before pay day, set by your bank's lead time and your checking step rather than by convention.
Why does a correction take until next period?
Because the submission has gone. Paying it as a labelled adjustment keeps the record explainable when somebody queries a payslip.