This one's older than the internet: type a number into a calculator, flip the whole thing upside down, and certain digits suddenly look like letters. It works because on a seven-segment display, 0 looks like O, 1 looks like I, 3 looks like E, 5 looks like S, 7 looks like L, 8 looks like B, and 4 or 6 can pass for h or g — all upside down.
The trick is older than most people assume — it goes back to the 1970s, when pocket calculators first became cheap enough for students to own. Teachers actually banned "calculator spelling" in some classrooms because kids were passing notes in class this way instead of doing arithmetic, which is a big part of how the trick spread by word of mouth for decades before the internet existed to document it.
It only works reliably on a seven-segment display — the classic red or LCD digit style made of straight line segments, not the rounded, realistic digit fonts used on some modern phone calculator apps. That's why this trick is more fun on an actual physical calculator or a calculator app styled to look like one (like our Basic Calculator) than on a plain system calculator with a rounded font — the letters simply don't form as cleanly.
This one isn't an upside-down trick — it's a numeric code. "143" comes from counting letters: "I" is 1 letter, "love" is 4 letters, "you" is 3 letters. It became shorthand for "I love you" in pager and early texting culture long before smartphones existed, and it's still used today.
The lighthouse at Rockland Breakwater in Maine actually became locally famous for flashing "I love you" in Morse-adjacent light patterns tied to this same 1-4-3 counting logic, and Mister Rogers reportedly used 143 as a personal shorthand for years — he mentioned in interviews that his weight famously stayed at 143 lbs for most of his adult life, which he considered a happy coincidence with the phrase's meaning. Numeric codes like this were common shorthand in the pager era because pagers could only display digits, not letters, so anything you wanted to say had to be translated into a number first.
Yes — Apple's Calculator app has shipped built into macOS and iOS for decades, with basic and scientific modes (turn an iPhone sideways to unlock the scientific layout). It's a real, first-party Apple app, not a third-party add-on.
Not every word you'd want to spell is possible — the seven-segment alphabet is limited to letters that can be formed from straight lines, so anything needing a true curve (like C, K, M, N, U, V, W, X, Y) either doesn't work at all or only works as a rough approximation. That's why calculator-word lists lean heavily on words built from O, I, L, S, E, B, G, Z, and H — those are the letters the display can actually reproduce cleanly upside down. It's also why longer, more elaborate "words" in these lists (like EGGSHELL) tend to need more digits than a short common word — there just aren't many valid upside-down letters to work with, so the vocabulary is naturally small and a little quirky.
Grab our Basic Calculator (works on any device) and try a few of the words above — or see how many new ones you can find on your own.
Sources: Wikipedia — Calculator spelling, Dictionary.com — 17 Calculator Words