diff --git a/src/app-utils/date-utilities.scm b/src/app-utils/date-utilities.scm
index 03faa8fa81..72eb0f35ec 100644
--- a/src/app-utils/date-utilities.scm
+++ b/src/app-utils/date-utilities.scm
@@ -198,7 +198,7 @@
   (/ (- (/ (/ caltime 3600.0) 24) 3) 7))
 
 (define (gnc:date-to-week caltime)
-  (quotient (- (quotient caltime 86400) 3) 7))
+  (floor (/ (- (/ caltime 86400) 3) 7)))
 
 ;; convert a date in seconds since 1970 into # of days since Feb 28, 1970
 ;; ignoring leap-seconds
diff --git a/src/app-utils/test/CMakeLists.txt b/src/app-utils/test/CMakeLists.txt
index b525b809fb..dc474784a4 100644
--- a/src/app-utils/test/CMakeLists.txt
+++ b/src/app-utils/test/CMakeLists.txt
@@ -29,5 +29,7 @@ GNC_ADD_SCHEME_TEST(scm-test-load-module test-load-module.in)
 
 CONFIGURE_FILE(test-load-module.in test-load-module @ONLY)
 
+GNC_ADD_SCHEME_TEST(scm-test-date-utilities test-date-utilities.scm)
+
 SET_DIST_LIST(test_app_utils_DIST CMakeLists.txt Makefile.am test-exp-parser.c test-link-module.c test-load-module.in
-        test-print-parse-amount.c test-print-queries.c test-scm-query-string.c test-sx.c)
\ No newline at end of file
+        test-print-parse-amount.c test-print-queries.c test-scm-query-string.c test-sx.c test-date-utilities.scm)
diff --git a/src/app-utils/test/Makefile.am b/src/app-utils/test/Makefile.am
index 6fb6a95573..b78f046a64 100644
--- a/src/app-utils/test/Makefile.am
+++ b/src/app-utils/test/Makefile.am
@@ -4,6 +4,7 @@ TESTS = \
   test-exp-parser \
   test-scm-query-string \
   test-print-parse-amount \
+  test-date-utilities \
   test-sx
 
 test_exp_parser_SOURCES = \
diff --git a/src/app-utils/test/test-date-utilities.scm b/src/app-utils/test/test-date-utilities.scm
new file mode 100644
index 0000000000..6fca517300
--- /dev/null
+++ b/src/app-utils/test/test-date-utilities.scm
@@ -0,0 +1,38 @@
+(use-modules (gnucash gnc-module))
+(gnc:module-begin-syntax (gnc:module-load "gnucash/app-utils" 0))
+(use-modules (gnucash engine test test-extras))
+
+(define (run-test)
+  (and (test test-weeknum-calculator)))
+
+(define (create-time64 l)
+  (let ((now (gnc-localtime (current-time))))
+    (set-tm:sec now (list-ref l 5))
+    (set-tm:min now (list-ref l 4))
+    (set-tm:hour now (list-ref l 3))
+    (set-tm:mday now (list-ref l 2))
+    (set-tm:mon now (list-ref l 1))
+    (set-tm:year now (list-ref l 0))
+    (set-tm:isdst now -1)
+    (gnc-mktime now)))
+
+(define (weeknums-equal? pair-of-dates)
+  (let ((d1 (car pair-of-dates))
+        (d2 (cdr pair-of-dates)))
+    (equal? (gnc:date-to-week (create-time64 d1))
+            (gnc:date-to-week (create-time64 d2)))))
+
+(define (test-weeknum-calculator)
+  (and (weeknums-equal? (cons '(1970 1 1 0 0 0)
+                              '(1970 1 1 23 59 59)))
+       (weeknums-equal? (cons '(1969 12 31 0 0 0)
+                              '(1969 12 31 23 59 59)))
+       (weeknums-equal? (cons '(1969 12 31 0 0 0)
+                              '(1970 1 1 0 0 1)))
+       (weeknums-equal? (cons '(2001 1 1 0 0 0)
+                              '(2001 1 1 23 59 59)))
+       (not (weeknums-equal? (cons '(1970 1 1 0 0 0)
+                                   '(1970 1 10 0 0 1))))
+       (not (weeknums-equal? (cons '(1969 12 28 0 0 1)
+                                   '(1970 1 5 0 0 1))))
+       ))