The question everyone types
Short answer: as old as its serial number says — and the serial number is a lookup, not a riddle. Singer kept a register of every block of serial numbers it handed to its factories, with the date each block was allotted. Find your number, match the block, and you have the year, the factory, and the machine class in one step.
One box, three brands. Pick the brand, type the number exactly as you find it on the machine, and read the answer with the record it came from.
It is stamped into the cast-iron bed of the machine. On most pre-1950s machines it sits on top of the bed at the front-right corner; on later machines it is on a raised pad under the bed, near the edge. Two traps catch nearly everyone:
The motor number is not it. The number on the motor dates the motor, at best. Ignore it.
Two numbers on the bed? Use the longer, higher one — the short one is a part or casting number that appears in no register. The full walk-through, with the other brands, is on the serial number location guide.
A machine from before about 1900. The surviving year table starts at 611,000 in 1871 and runs to 1899; below that, your machine is from Singer's first two decades.
About 1900 to the mid-1920s. The letter is the factory series — G is the long Elizabethport run, F and Y are Kilbowie in Scotland, and so on.
1924 into the 1960s. The letters give the factory series (AK is Elizabethport, 1951–52); the block gives the exact allotment date.
The register date is the day Singer allotted that block of numbers to a factory. The machines were built from the block shortly after — usually weeks or months. So the year is the machine's year in every practical sense, and it is also, honestly, an allotment year: a documented 1939 block reached a customer in 1946 after the war intervened. Every result on this site prints the allotment date itself, so you always know exactly which fact you are holding.
Want the full register, the prefix table for all 65 series, and the machine-class detail? The Singer serial number lookup page prints the whole map. Dating a Kenmore or an Elna instead? Those numbers work completely differently — Kenmore dates from its model number, Elna from its letter code.
Knowing the year is the start of the two questions that follow: is it worth selling, and is it safe to use? The kit answers both — sold-price ranges by model, and the wiring and cleaning checks a 70-to-170-year-old machine needs before power.
Included in the $39 Seller & Restore Kit