remotion-dev/remotion · error · TypeError

Parameter 'durationInMilliseconds' must be a number but got

Error message

Parameter 'durationInMilliseconds' must be a number but got ${typeof durationInMilliseconds}

What it means

estimatePrice runs a typeof check on the resolved durationInMilliseconds and throws a TypeError if it is not a number. The function accepts both the deprecated typo key durationInMiliseconds and the correct durationInMilliseconds, so a non-number usually means neither key was supplied (undefined) or a string/other type was passed.

Source

Thrown at packages/lambda-client/src/estimate-price.ts:47

 */
export const estimatePrice = ({
	region,
	memorySizeInMb,
	diskSizeInMb,
	lambdasInvoked,
	...other
}: EstimatePriceInput): number => {
	validateMemorySize(memorySizeInMb);
	validateAwsRegion(region);
	validateDiskSizeInMb(diskSizeInMb);

	const durationInMilliseconds =
		'durationInMiliseconds' in other
			? other.durationInMiliseconds
			: other.durationInMilliseconds;

	if (typeof durationInMilliseconds !== 'number') {
		throw new TypeError(
			`Parameter 'durationInMilliseconds' must be a number but got ${typeof durationInMilliseconds}`,
		);
	}

	if (Number.isNaN(durationInMilliseconds)) {
		throw new TypeError(
			`Parameter 'durationInMilliseconds' must not be NaN but it is.`,
		);
	}

	if (!Number.isFinite(durationInMilliseconds)) {
		throw new TypeError(
			`Parameter 'durationInMilliseconds' must be finite but it is ${durationInMilliseconds}`,
		);
	}

	if (durationInMilliseconds < 0) {
		throw new TypeError(

View on GitHub (pinned to 78fe4bb3fd)

Solutions

Pass durationInMilliseconds as a number
If using the deprecated durationInMiliseconds typo, rename it to durationInMilliseconds
Coerce/Number() only after confirming the source value is numeric

Example fix

// before
estimatePrice({ region, memorySizeInMb, diskSizeInMb, lambdasInvoked });

// after
estimatePrice({ region, memorySizeInMb, diskSizeInMb, lambdasInvoked, durationInMilliseconds: 5000 });

Defensive patterns

Strategy: validation

Validate before calling

function assertDuration(v: unknown): asserts v is number {
  if (typeof v !== 'number') {
    throw new TypeError('durationInMilliseconds must be a number');
  }
}

Type guard

const isDuration = (v: unknown): v is number => typeof v === 'number' && !Number.isNaN(v) && Number.isFinite(v) && v >= 0;

Prevention

Type the call site strictly so omitted durationInMilliseconds is a compile error
Migrate any durationInMiliseconds (typo) usages to durationInMilliseconds
Validate at the boundary where user input enters

When it happens

Trigger: Calling estimatePrice with no durationInMilliseconds (and no durationInMiliseconds), or with a non-numeric value such as a string.

Common situations: Object spread that dropped the field, renamed prop without updating call site, passing a string from user input.

Related errors

AI-assisted analysis of remotion-dev/remotion@78fe4bb3fd (2026-08-12). Data as JSON: /api/errors/e29be929585f0aae. Report an issue: GitHub.