diff --git a/ui/format_dialog.py b/ui/format_dialog.py
--- a/ui/format_dialog.py
+++ b/ui/format_dialog.py
@@ -20,6 +20,7 @@ class Ui_Dialog(object):
         self.gridLayout.setObjectName("gridLayout")
         self.sb_to = QtWidgets.QSpinBox(Dialog)
         self.sb_to.setObjectName("sb_to")
+        self.sb_to.setMaximum(999)
         self.gridLayout.addWidget(self.sb_to, 1, 1, 1, 1)
         self.label_2 = QtWidgets.QLabel(Dialog)
         self.label_2.setMaximumSize(QtCore.QSize(16777215, 16))
@@ -27,6 +28,7 @@ class Ui_Dialog(object):
         self.gridLayout.addWidget(self.label_2, 0, 1, 1, 1)
         self.sb_from = QtWidgets.QSpinBox(Dialog)
         self.sb_from.setObjectName("sb_from")
+        self.sb_from.setMaximum(999)
         self.gridLayout.addWidget(self.sb_from, 1, 0, 1, 1)
         self.label = QtWidgets.QLabel(Dialog)
         self.label.setMaximumSize(QtCore.QSize(16777215, 16))