How did pre-electronic cash registers work?

You know, the olde-timey kind where tabs would pop up with the dollars and cents in the little window. When adding prices, how did the register “remember” the previous total? How did it add? My WAG is that there was some mechanical abacus but I still can’t wrap my head around how that would work either.

WAG - they had a mechanism in them that functions essentially like an odometer, or any conventional wheeled counter. When you punched in, say, 4.56, three wheels were spun to that point. When you punched in, say, 4.95, all the wheels were advanced that amount, and the tabs on the wheels that tipped the next place value did their jobs, and the two figures were added. Seems pretty straightforward to me. But, of course, those are the things that are most deceptive. stay tuned.

I dont know how they worked, but I do remember the incredible speed with which the cashiers in the A&P used to work. They also worked by touch and never did look at the cash register.

I wonder how much my mother overpaid? (Probably not much, she has an eye for that sort of thing and counts pennies to this day).


My father has a bunch of old NCR cash registers. Have you ever seen inside one of those things? They’re built like a giant Swiss watch. Thousands of components. They’re engineering marvels.

Any chance you could get some photos and post them online?

(I can host if needed)

The really cool part was cashing one of those out at the end of the day. Lots of noise and receipt tape spitting out. It was a thing to behold. I think the manual register in my dad’s store gave out in the late 1970s. Then we had a really small electronic one. It was never quite the same.

Especially since I didn’t have to look at the sales tax table anymore.

IIRC there was a hand crank on the clerk’s right side that took account of the total, printed it on the internal tape, and opened the cash drawer.