As at / As of / With effect from / effective from
UsageUse as at for a snapshot at a date, and with effect from or effective from for the commencement of a change. As of is standard but can mean either at or from a date, so choose a more explicit expression where the distinction matters.
As at
Use when
You give a snapshot of a status, balance or count at a particular date.
Example
“There were 24 open cases as at 31 July 2026.”
As of
Use when
You mean at a stated date or, in some usage, from that date; use it only where the intended timing is clear.
Example
“As of 31 July 2026, 24 cases remained open.”
With effect from / effective from
Use when
You state the date on which a new rule, fee, appointment or other change begins to apply.
Example
“The revised fee applies with effect from 1 January 2027.”
Quick check
as at used for a commencement date, as of where at versus from is material, effective as at
Usage note
Formal Singapore documents commonly use as at for status and with effect from for commencement. Preserve the exact wording of legislation, contracts or official forms where it has a defined effect.