index.md

---

title: Less than
slug: WebAssembly/Reference/Numeric/Less_than

---

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The lt instructions, short for less than, check if a number is less than another number. If the first number is less than the second number equal 1 will be pushed on to the stack, otherwise 0 will be pushed on to the stack.

The integer types have separate less than instructions for signed (lt_s) and unsigned (lt_u) numbers.

{{EmbedInteractiveExample("pages/wat/lt.html", "tabbed-taller")}}

Syntax

;; load 2 numbers on to the stack
local.get $num
i32.const 2

;; check if $num is less then '2'
i32.lt_u

;; if $num is less than the `2`, `1` will be pushed on to the stack,
;; otherwise `0` will be pushed on to the stack.

Instruction	Binary opcode
i32.lt_s	0x48
i32.lt_u	0x49
i64.lt_s	0x53
i64.lt_u	0x54
f32.lt	0x5d
f64.lt	0x63