n8n-io/n8n · error · ExpressionExtensionError

cannot convert to float

Error message

cannot convert to float

What it means

toFloat() stripped currency symbols via CURRENCY_REGEXP and ran parseFloat, but the result was NaN — the remaining string had no leading numeric content at all. This is the generic conversion failure after the comma-separator case was already excluded.

Solutions

1. Check the input string actually starts with a number (whitespace, letters, or symbols before the digits cause NaN)
2. Pre-clean the string in a Code node: strip units, labels, and stray characters
3. Use .isNumeric() or a regex test before calling toFloat() when the format is uncertain

When it happens

Trigger: Thrown at packages/@n8n/expression-runtime/src/extensions/string-extensions.ts:250 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of n8n-io/n8n@5ac6606e81 (2026-08-12). Data as JSON: /api/errors/7e51336067d1d66d. Report an issue: GitHub.

Appendix: source

Thrown at packages/@n8n/expression-runtime/src/extensions/string-extensions.ts:250

	const [radix] = extraArgs;
	const int = parseInt(value.replace(CURRENCY_REGEXP, ''), radix);

	if (isNaN(int)) {
		throw new ExpressionExtensionError('cannot convert to integer');
	}

	return int;
}

function toFloat(value: string) {
	if (value.includes(',')) {
		throw new ExpressionExtensionError('cannot convert to float, expected . as decimal separator');
	}

	const float = parseFloat(value.replace(CURRENCY_REGEXP, ''));

	if (isNaN(float)) {
		throw new ExpressionExtensionError('cannot convert to float');
	}

	return float;
}

function toNumber(value: string) {
	const num = Number(value.replace(CURRENCY_REGEXP, ''));

	if (isNaN(num)) {
		throw new ExpressionExtensionError('cannot convert to number');
	}

	return num;
}

function quote(value: string, extraArgs: string[]) {
	const [quoteChar = '"'] = extraArgs;
	return `${quoteChar}${value

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