diff --git a/.changeset/event-helper-rrule.md b/.changeset/event-helper-rrule.md
new file mode 100644
index 0000000..2ddda8c
--- /dev/null
+++ b/.changeset/event-helper-rrule.md
@@ -0,0 +1,6 @@
+---
+"@churchapps/helpers": patch
+"@churchapps/apphelper": patch
+---
+
+Rebuild weekly RRules from the event start date and match exception dates by calendar day.
diff --git a/apphelper/src/website/components/eventCalendar/RRuleEditor.tsx b/apphelper/src/website/components/eventCalendar/RRuleEditor.tsx
index 74b2cbe..7b7a2a4 100644
--- a/apphelper/src/website/components/eventCalendar/RRuleEditor.tsx
+++ b/apphelper/src/website/components/eventCalendar/RRuleEditor.tsx
@@ -166,6 +166,25 @@ export function RRuleEditor(props: Props) {
     props.onChange(result);
   }, [rRuleOptions, props.onChange]);
 
+  const startDateKey = `${props.start.getFullYear()}-${props.start.getMonth()}-${props.start.getDate()}`;
+  const prevStartDateKey = React.useRef(startDateKey);
+  useEffect(() => {
+    if (prevStartDateKey.current === startDateKey) return;
+    prevStartDateKey.current = startDateKey;
+    setRRuleOptions((prev) => {
+      const options = { ...prev, dtstart: props.start };
+      // Only weekly rules are pinned to the start date's weekday; daily rules must stay every-day.
+      if (options.freq === RRule.WEEKLY) {
+        let startDay = props.start.getDay() - 1;
+        if (startDay === -1) startDay = 6;
+        options.byweekday = [startDay];
+      } else if (options.freq === RRule.MONTHLY && options.bymonthday?.length > 0) {
+        options.bymonthday = [props.start.getDate() || 1];
+      }
+      return options;
+    });
+  }, [startDateKey, props.start]);
+
   return (
     <>
       <Grid size={{ xs: 2 }}>
diff --git a/helpers/src/EventHelper.ts b/helpers/src/EventHelper.ts
index 2b67f51..4d7d8e3 100644
--- a/helpers/src/EventHelper.ts
+++ b/helpers/src/EventHelper.ts
@@ -50,17 +50,24 @@ export class EventHelper {
 
   static getFullRRule = (event:EventInterface) => {
     const RR = getRRule();
-    const rrule = RR.fromString(event.recurrenceRule);
-    rrule.options.dtstart = new Date(event.start!);
-    return rrule;
+    // Reconstruct so implicit BYDAY/BYMONTHDAY derive from event.start, not parse-time "now".
+    const options = { ...RR.parseString(event.recurrenceRule || "") };
+    options.dtstart = new Date(event.start!);
+    return new RR(options);
+  };
+
+  static calendarDateKey = (d: string | Date) => {
+    const dt = new Date(d);
+    if (isNaN(dt.getTime())) return "";
+    return `${dt.getFullYear()}-${dt.getMonth()}-${dt.getDate()}`;
   };
 
   static removeExcludeDates = (events:EventInterface[]) => {
     for (let i = events.length - 1; i >= 0; i--) {
       const exceptionDates = events[i].exceptionDates;
       if (exceptionDates && exceptionDates.length > 0) {
-        const parsedDates = exceptionDates.map((d: string | Date)=>new Date(d).toISOString());
-        if (parsedDates.indexOf(events[i].start!.toISOString()) > -1) events.splice(i, 1);
+        const keys = exceptionDates.map((d: string | Date) => EventHelper.calendarDateKey(d));
+        if (keys.indexOf(EventHelper.calendarDateKey(events[i].start!)) > -1) events.splice(i, 1);
       }
     }
   };
diff --git a/helpers/tests/eventHelper.test.ts b/helpers/tests/eventHelper.test.ts
new file mode 100644
index 0000000..66b3d3d
--- /dev/null
+++ b/helpers/tests/eventHelper.test.ts
@@ -0,0 +1,55 @@
+import { test } from "node:test";
+import assert from "node:assert/strict";
+
+import { EventHelper } from "../src/EventHelper";
+import type { EventInterface } from "../src/interfaces";
+
+await EventHelper.ensureInitialized();
+
+const localKey = (d: Date) => `${d.getFullYear()}-${d.getMonth() + 1}-${d.getDate()}`;
+
+test("getFullRRule includes the selected start date for weekly rules without BYDAY", () => {
+  // Thursday Jan 8, 2026 — the reporter's "1st date selected"
+  const start = new Date(2026, 0, 8, 18, 30, 0);
+  const event: EventInterface = {
+    start,
+    end: new Date(2026, 0, 8, 20, 0, 0),
+    recurrenceRule: "FREQ=WEEKLY;INTERVAL=1;UNTIL=20260301T235959Z"
+  };
+  const range = EventHelper.getRange(event, new Date(2026, 0, 1), new Date(2026, 0, 31, 23, 59, 59));
+  const dates = range.map(localKey);
+  assert.ok(dates.includes("2026-1-8"), `first occurrence missing, got ${dates.join(",")}`);
+  for (const d of range) assert.equal(d.getDay(), 4, "weekly series should stay on Thursday");
+});
+
+test("getFullRRule still honors an explicit BYDAY", () => {
+  const start = new Date(2026, 6, 1, 18, 30, 0); // Wednesday
+  const event: EventInterface = {
+    start,
+    end: new Date(2026, 6, 1, 20, 0, 0),
+    recurrenceRule: "FREQ=WEEKLY;BYDAY=WE"
+  };
+  const range = EventHelper.getRange(event, new Date(2026, 6, 1), new Date(2026, 6, 31, 23, 59, 59));
+  assert.ok(range.length >= 4);
+  for (const d of range) assert.equal(d.getDay(), 3);
+});
+
+test("removeExcludeDates drops an occurrence matched by calendar date, not exact ISO timestamp", () => {
+  const start = new Date(2026, 0, 8, 18, 30, 0);
+  const events: EventInterface[] = [
+    { id: "keep", start: new Date(2026, 0, 15, 18, 30, 0), exceptionDates: [new Date(2026, 0, 8, 12, 0, 0)] as any },
+    { id: "drop", start, exceptionDates: [new Date(2026, 0, 8, 12, 0, 0)] as any }
+  ];
+  EventHelper.removeExcludeDates(events);
+  assert.equal(events.length, 1);
+  assert.equal(events[0].id, "keep");
+});
+
+test("removeExcludeDates matches mysql-style datetime strings that would fail ISO equality", () => {
+  const start = new Date(2026, 0, 8, 18, 30, 0);
+  const events: EventInterface[] = [
+    { id: "drop", start, exceptionDates: ["2026-01-08 12:00:00"] as any }
+  ];
+  EventHelper.removeExcludeDates(events);
+  assert.equal(events.length, 0);
+});