Math, Parsing & BigDecimal in Java

From the Java cheat sheet · Math & Numbers · verified Jul 2026

Common numeric operations and gotchas.

java

// Quick Reference
Math.max(3, 7);   Math.abs(-5);   Math.pow(2, 10);
Math.sqrt(16);    Math.round(3.6);
int n = Integer.parseInt("42");

💡 Floating-point math is inexact - use BigDecimal (from a String) for money.

⚡ Compare BigDecimals with compareTo(); equals() also checks scale (2.0 != 2.00).

📌 Integer.parseInt(s, radix) parses binary/hex/octal; parseInt throws on bad input.

🟢 Math.round returns long/int; Math.floor/ceil return double.

mathbigdecimalparsing