Payment in full describes the complete discharge of a monetary obligation so that no further sums are owed under a contract, judgment, invoice, loan, tax assessment or other debt. In legal practice across England and Wales, Scotland, Northern Ireland and Ireland, it signifies that the debtor has satisfied the whole amount due, including (where applicable) interest, costs and contractual or statutory charges.The expression is primarily descriptive, used in contracts, settlement agreements, receipts, letters before action and court documents, rather than being defined in a single statute. Its legal effect is determined by general principles of contract, debt and, where relevant, accord and satisfaction or compromise of proceedings.Key issues for practitioners include: whether the sum tendered genuinely represents all sums due; whether “payment in full and final settlement” has been clearly agreed; interaction with part‑payment rules (e.g. Foakes v Beer–type principles in UK jurisdictions); and evidential questions, such as receipts or remittance advice marked “paid in full”.Usage is broadly consistent across the UK and Ireland, though terminology may interact with different procedural rules on enforcement, prescription/limitation and formal discharge of decrees or judgments.