A Guarantor's Liability and Zakat

Short answer: (1) A guarantee is a contingent liability — while the principal debtor keeps paying, nothing has left your wealth; it therefore has no effect on your zakat, which falls on your full wealth as usual. (2) If he defaults and you pay from your own pocket: what you paid is spent — out of the books; and a receivable against the debtor arises for that amount — a strong debt if he is solvent and acknowledging (counted yearly), else weak (upon recovery). Details: Standing guarantor is noble cooperation but a risky charge — the Prophet ﷺ said 'the guarantor is liable' (Abu Dawud 3565, Tirmidhi 1265; sahih per al-Albani). Do not guarantee beyond your means, and document it. Note: guaranteeing an interest-bearing loan joins you to a riba contract — evidence-based scholars counsel against it; repent if already done and do not repeat. A guarantor genuinely impoverished by a default becomes himself entitled to zakat under the ghārimīn category. Evidence: Abu Dawud 3565 (sahih per al-Albani); Quran 9:103 (zakat on existing wealth — contingent liabilities do not shrink it); Quran 9:60; Shaykh al-Uthaymin on future/uncertain liabilities. For complex individual cases, consult a qualified scholar.