Looking for a lowered b?
Quick answer: Unicode has no standard Latin subscript b. Tap ᵦ (Greek beta) or B₂ if you meant boron with a 2.
Closest to a lowered b
f is the same story: no Latin lowered f. Use f₂ or leave f normal.
Why Word still “works” and chat does not
Word can shrink any letter with Format → Subscript. That style dies in WhatsApp. Only characters that exist in Unicode travel. The official Latin set (U+2090–U+209C) is short: ₐ ₑ ₒ ₓ ₕ ₖ ₗ ₘ ₙ ₚ ₛ ₜ plus schwa. Extra phonetic marks (ᵢ ⱼ ᵣ ᵤ ᵥ) exist in some fonts and fail in others.
Math people often want x_b or a_f. Those are written as xᵦ or x with a normal b if the reader’s font lacks beta. In a paper you can keep Word styling. In a chat or a slide that will be copied out, pick a letter that exists (ₓ ₙ) or keep the index as a normal letter.
Our converter maps only the official Latin set above. Type “b” or “f” and they stay b and f. That is deliberate. Inventing a fake glyph would show as a box on half the phones in a class WhatsApp group.
On a phone, tap ᵦ or B₂, switch to the chat or slide, long-press, Paste. On a computer, click the chip, then Ctrl + V or Cmd + V. If you see a box, the font lacks that mark — keep a normal b rather than forcing a fake subscript.
Use B₂ when the 2 is a real index (boron, a second item). Use ᵦ when you only need the look of a small b and the reader will accept Greek. For homework that must stay Latin, leave b normal and say so once in the caption.
Subscript letters that actually exist
These subscript letters are the ones our converter maps. Tap one. Missing glyphs stay as normal Latin so you do not get a box.
Digits ₀–₉ are on the ₂ copy page.
After you pick a stand-in
If you came for subscript b and left with ᵦ or B₂, that is the real limit of Unicode, not a broken tool. Build longer strings on the homepage converter.