Zod · Function

z.number

z.number() creates a Zod schema for finite numeric values. Chain numeric checks such as bounds, positivity, and divisibility to express stricter requirements.

How it works

Call z.number() to create a schema for numeric input. It accepts finite numbers, rejects NaN and infinities, and can be refined with numeric constraints such as bounds, positivity, and divisibility.

Syntax

z.number()

Returns

A Zod number schema that validates finite numbers and supports number-specific constraints.

Key points

Create a numeric validator with z.number().
gt enforces a strict lower bound.
gte includes the boundary and is also available as min.
lt enforces a strict upper bound.
lte includes the boundary and is also available as max.
positive requires a value greater than zero and aliases gt(0).
nonnegative permits zero and positive values.

Common mistakes

Infinity and NaN are not accepted; the base schema is limited to finite numeric values.
Use multipleOf or its step alias when validating divisibility; do not confuse it with a range constraint.

Example: Validate a bounded score

import { z } from "zod";

const score = z.number().int().min(0).max(100);

console.log(score.parse(85));
// score.parse(85.5); // throws a validation error
// score.parse(Infinity); // throws a validation error

Creates an integer number schema restricted to the inclusive range 0 through 100, then parses a valid score.

When to use it

Input validation

Validate numeric fields from application input before using them in calculations or persistence.

Constrained integers

Combine bounds and integer checks for values such as scores, counts, or quantities.

Step-based values

Require regular numeric intervals, such as prices or measurements divisible by a fixed increment.

Interview questions

QWhat does z.number() validate?

z.number() constructs a schema that validates numeric values. The base schema accepts finite numbers and rejects NaN and Infinity.

Follow-up: How would you restrict values to positive integers? Chain the documented numeric constraints, for example z.number().int().positive().

QHow do you add numeric bounds?

Use gt or gte for lower bounds and lt or lte for upper bounds. The documentation identifies min as an alias for gte and max as an alias for lte.

Follow-up: How would you require a value from 1 through 10 inclusively? Use z.number().gte(1).lte(10), or the equivalent min and max aliases.

QHow do you validate a number's step or divisibility?

The number schema supports multipleOf for divisibility, with step as its alias. For example, z.number().multipleOf(5) accepts values evenly divisible by five.

Follow-up: How could this be combined with a range? Chain the divisibility constraint with bound methods, such as z.number().multipleOf(5).gte(0).lte(100).

z.int
z.float32
z.float64
z.coerce.number
z.record

Source: Defining schemas | Zod. Checked 2026-10-15.