Upside Down 1
There is no true upside down 1, so ⇂ is used instead.
A digit 1 is a vertical stroke with a small flag at the top left. Turned through 180 degrees the flag would hang at the bottom right. Unicode has no such digit, but the arrow ⇂ (U+21C2, Downwards Harpoon With Barb Rightwards) has exactly that outline, which is why flip tables choose it. Another popular lookalike is Ɩ (U+0196, Latin Capital Letter Iota), which has two serifs.
| Normal number | 1 |
|---|---|
| Flipped | ⇂ |
| Unicode name | Downwards Harpoon With Barb Rightwards |
| Code point | U+21C2 |
| Other lookalike | Ɩ (U+0196) |
Where you will see ⇂
Pocket calculators gave the flipped 1 its fame: turned over, 1 reads as the letter I, so 51 reads as IS. Online, ⇂ shows up in flipped lists and countdowns. It is an arrow from the symbols block, so apps may draw it in a symbol font where it looks smaller than the digits around it.
Copy and paste examples
1→⇂10→0⇂2001→⇂00ᘔ111→⇂⇂⇂
Good to know
Can I use I instead of ⇂?
On a calculator, yes: a turned 1 reads as I. For a visual match in text, ⇂ is closer, but the capital I is more compatible.
All the flipped numbers are listed on the numbers page, or type a whole sentence into the upside down text generator.