diff --git a/math/qalculate-qt/Makefile b/math/qalculate-qt/Makefile
index 1669d9890650..6fa230c8abd2 100644
--- a/math/qalculate-qt/Makefile
+++ b/math/qalculate-qt/Makefile
@@ -1,23 +1,26 @@
 PORTNAME=	qalculate-qt
-PORTVERSION=	5.8.2
+PORTVERSION=	5.9.0
 CATEGORIES=	math
 MASTER_SITES=	https://github.com/Qalculate/${PORTNAME}/releases/download/v${PORTVERSION}/
 
 MAINTAINER=	jhale@FreeBSD.org
 COMMENT=	Multi-purpose desktop calculator (Qt frontend)
 WWW=		https://qalculate.github.io/
 
 LICENSE=	GPLv2+
 LICENSE_FILE=	${WRKSRC}/COPYING
 
 LIB_DEPENDS=	libqalculate.so:math/libqalculate
 RUN_DEPENDS=	gnuplot:math/gnuplot
 
 USES=		compiler:c++17-lang gl pkgconfig qmake qt:6
+# Project does not set a c++ dialect, but it's better to not leave this
+# undefined and left up to the whims of the compiler.
+USE_CXXSTD=	c++17
 USE_GL=		opengl
 USE_QT=		base tools:build
 
 OPTIONS_DEFINE=	NLS
 OPTIONS_SUB=	yes
 
 .include <bsd.port.mk>
diff --git a/math/qalculate-qt/distinfo b/math/qalculate-qt/distinfo
index b4140a8022ab..f8988ca09e22 100644
--- a/math/qalculate-qt/distinfo
+++ b/math/qalculate-qt/distinfo
@@ -1,3 +1,3 @@
-TIMESTAMP = 1763448171
-SHA256 (qalculate-qt-5.8.2.tar.gz) = ebf547910ce5c5624b8d158873ff88c4379288cc687993e50655f9f7ead171ae
-SIZE (qalculate-qt-5.8.2.tar.gz) = 2027585
+TIMESTAMP = 1768984815
+SHA256 (qalculate-qt-5.9.0.tar.gz) = c018e8ccc4c48c5c831d28c32b960f77de1c7e0e8cb6e26e0b9a2cccc91e5ee3
+SIZE (qalculate-qt-5.9.0.tar.gz) = 2043503