What is 4/81 as a percentage? It is 4.94% (rounded to two decimal places).
The fraction 4/81 is a small part of a whole, showing up when you split something into 81 equal pieces and take four of them. In decimal form it is about 0.049, which is why the percentage is just under five percent.
You might see 4/81 in problems about probability, like the chance of drawing a specific card from a 81‑card deck, or in simple financial examples where a tiny interest rate is needed. Knowing the percentage makes it easier to compare with other numbers you encounter every day.