diff --git a/kerfuffle/propertiesdialog.h b/kerfuffle/propertiesdialog.h
--- a/kerfuffle/propertiesdialog.h
+++ b/kerfuffle/propertiesdialog.h
@@ -32,7 +32,8 @@
 
 #include <QCryptographicHash>
 #include <QDialog>
-#include <QFuture>
+
+class QLabel;
 
 namespace Kerfuffle
 {
@@ -43,17 +44,11 @@
 public:
     explicit PropertiesDialog(QWidget *parent, Archive *archive);
 
-private slots:
-    void slotShowSha1();
-    void slotShowSha256();
-
 private:
-    QString calcHash(QCryptographicHash::Algorithm algorithm);
+    QString calcHash(QCryptographicHash::Algorithm algorithm, const QString &path);
+    void showChecksum(QCryptographicHash::Algorithm algorithm, const QString &fileName, QLabel *label);
 
     class PropertiesDialogUI *m_ui;
-    QByteArray m_byteArray;
-    QFuture<QString> m_futureCalcSha1;
-    QFuture<QString> m_futureCalcSha256;
 };
 }
 
diff --git a/kerfuffle/propertiesdialog.cpp b/kerfuffle/propertiesdialog.cpp
--- a/kerfuffle/propertiesdialog.cpp
+++ b/kerfuffle/propertiesdialog.cpp
@@ -99,53 +99,41 @@
     QIcon icon = QIcon::fromTheme(archive->mimeType().iconName());
     m_ui->lblIcon->setPixmap(icon.pixmap(IconSize(KIconLoader::Desktop), IconSize(KIconLoader::Desktop)));
 
+    m_ui->lblMD5->setText(i18n("Calculating..."));
     m_ui->lblSHA1->setText(i18n("Calculating..."));
     m_ui->lblSHA256->setText(i18n("Calculating..."));
 
-    QFile file(archive->fileName());
-    if (file.open(QIODevice::ReadOnly)) {
-        m_byteArray = file.readAll();
-        file.close();
-
-        QCryptographicHash hashMD5(QCryptographicHash::Md5);
-        hashMD5.addData(m_byteArray);
-        m_ui->lblMD5->setText(QLatin1String(hashMD5.result().toHex()));
-
-        // The two SHA hashes take some time to calculate, so run them in another thread.
-        QFutureWatcher<QString> *watchCalcSha1 = new QFutureWatcher<QString>;
-        connect(watchCalcSha1, SIGNAL(finished()), this, SLOT(slotShowSha1()));
-        m_futureCalcSha1 = QtConcurrent::run(this, &PropertiesDialog::calcHash, QCryptographicHash::Sha1);
-        watchCalcSha1->setFuture(m_futureCalcSha1);
-
-        QFutureWatcher<QString> *watchCalcSha256 = new QFutureWatcher<QString>;
-        connect(watchCalcSha256, SIGNAL(finished()), this, SLOT(slotShowSha256()));
-        m_futureCalcSha256 = QtConcurrent::run(this, &PropertiesDialog::calcHash, QCryptographicHash::Sha256);
-        watchCalcSha256->setFuture(m_futureCalcSha256);
-    } else {
-        m_ui->lblMD5->setText(QString());
-        m_ui->lblSHA1->setText(QString());
-        m_ui->lblSHA256->setText(QString());
-    }
+    showChecksum(QCryptographicHash::Md5, archive->fileName(), m_ui->lblMD5);
+    showChecksum(QCryptographicHash::Sha1, archive->fileName(), m_ui->lblSHA1);
+    showChecksum(QCryptographicHash::Sha256, archive->fileName(), m_ui->lblSHA256);
 
     connect(m_ui->buttonBox, &QDialogButtonBox::accepted, this, &QDialog::accept);
 }
 
-QString PropertiesDialog::calcHash(QCryptographicHash::Algorithm algorithm)
+QString PropertiesDialog::calcHash(QCryptographicHash::Algorithm algorithm, const QString &path)
 {
-    QCryptographicHash hash(algorithm);
-    hash.addData(m_byteArray);
+    QFile file(path);
+    if (!file.open(QIODevice::ReadOnly)) {
+        return QString();
+    }
 
-    return QLatin1String(hash.result().toHex());
-}
+    QCryptographicHash hash(algorithm);
+    hash.addData(&file);
 
-void PropertiesDialog::slotShowSha1()
-{
-    m_ui->lblSHA1->setText(m_futureCalcSha1.result());
+    return QString::fromLatin1(hash.result().toHex());
 }
 
-void PropertiesDialog::slotShowSha256()
+void PropertiesDialog::showChecksum(QCryptographicHash::Algorithm algorithm, const QString &fileName, QLabel *label)
 {
-    m_ui->lblSHA256->setText(m_futureCalcSha256.result());
+    // Calculate checksum in another thread.
+    auto futureWatcher = new QFutureWatcher<QString>(this);
+    connect(futureWatcher, &QFutureWatcher<QString>::finished, this, [=]() {
+        label->setText(futureWatcher->result());
+        futureWatcher->deleteLater();
+    });
+
+    auto future = QtConcurrent::run(this, &PropertiesDialog::calcHash, algorithm, fileName);
+    futureWatcher->setFuture(future);
 }
 
 }