diff --git a/packages/taler-util/src/payto.ts b/packages/taler-util/src/payto.ts
index 60c4ba838..85870afcd 100644
--- a/packages/taler-util/src/payto.ts
+++ b/packages/taler-util/src/payto.ts
@@ -89,12 +89,13 @@ export function buildPayto(
       return result;
     }
     case "iban": {
+      const uppercased = first.toUpperCase()
       const result: PaytoUriIBAN = {
         isKnown: true,
         targetType: "iban",
-        iban: first,
+        iban: uppercased,
         params: {},
-        targetPath: !second ? first : `${second}/${first}`,
+        targetPath: !second ? uppercased : `${second}/${uppercased}`,
       };
       return result;
     }
@@ -200,13 +201,13 @@ export function parsePaytoUri(s: string): PaytoUri | undefined {
     let iban: string | undefined = undefined;
     let bic: string | undefined = undefined;
     if (parts.length === 1) {
-      iban = parts[0];
+      iban = parts[0].toUpperCase();
     }
     if (parts.length === 2) {
       bic = parts[0];
-      iban = parts[1];
+      iban = parts[1].toUpperCase();
     } else {
-      iban = targetPath;
+      iban = targetPath.toUpperCase();
     }
     return {
       isKnown: true,