What causes "can't divide the value by 0" in gohugoio/hugo?

Guard the division: `{{ if gt $n 0 }}{{ div $total $n }}{{ end }}`.

can't divide the value by 0

Error message

can't divide the value by 0

What it means

In DoArithmetic's '/' branch, the division is only performed when the denominator is non-zero for the resolved type class (int, float, or uint). A zero denominator falls through to this error at common/math/math.go:129, so Hugo's `div` template function reports division by zero instead of panicking.

Source

Thrown at common/math/math.go:129

			return af - bf, nil
		}
		return au - bu, nil
	case '*':
		if isInt {
			return ai * bi, nil
		} else if isFloat {
			return af * bf, nil
		}
		return au * bu, nil
	case '/':
		if isInt && bi != 0 {
			return ai / bi, nil
		} else if isFloat && bf != 0 {
			return af / bf, nil
		} else if isUint && bu != 0 {
			return au / bu, nil
		}
		return nil, errors.New("can't divide the value by 0")
	default:
		return nil, errors.New("there is no such an operation")
	}
}

View on GitHub ↗ (pinned to 8a468df065)

Solutions

Guard the division: `{{ if gt $n 0 }}{{ div $total $n }}{{ end }}`.
Use `default` to substitute a safe non-zero divisor when the value may be unset.
Trace why the divisor is zero (empty section, missing param) and fix the data or the collection filter.

Example fix

{{/* before */}}
{{ div $sum (len $pages) }}

{{/* after */}}
{{ with len $pages }}{{ div $sum . }}{{ else }}0{{ end }}

Defensive patterns

Strategy: validation

Validate before calling

if divisor == 0 { // handle explicitly: skip, error, or use a guarded expression
}
// template: {{ if ne $n 0 }}{{ div $x $n }}{{ end }}

Try / catch

v, err := math.DoArithmetic(x, n, '/')
if err != nil {
	// zero divisor: surface the error; don't silently substitute 0
}

Prevention

Guard every division whose divisor comes from data (page counts, lengths) with a zero check.
Use `len` checks before computing averages over possibly-empty collections.
Note integer division by zero errors while float division may not — normalize types deliberately.

When it happens

Trigger: `{{ div x y }}` (or `math.Div`) where y evaluates to 0 or 0.0 — including a missing/unset param defaulting to 0, `len` of an empty collection, or a computed counter that is zero.

Common situations: Computing percentages or averages where the divisor is `len` of a possibly-empty page collection or slice; pagination/ratio math on sites with no matching content; params that default to 0 when absent.

Related errors

AI-assisted analysis of gohugoio/hugo@8a468df065 (2026-07-31). Data as JSON: /data/errors/c2d46987f9afe765.json. Report an issue: GitHub ↗.