diff --git a/Userland/Applications/Calculator/CalculatorWidget.cpp b/Userland/Applications/Calculator/CalculatorWidget.cpp
index 385df9bee9..e10f048ecb 100644
--- a/Userland/Applications/Calculator/CalculatorWidget.cpp
+++ b/Userland/Applications/Calculator/CalculatorWidget.cpp
@@ -28,7 +28,7 @@ CalculatorWidget::CalculatorWidget()
     m_label->set_frame_style(Gfx::FrameStyle::SunkenContainer);
 
     for (int i = 0; i < 10; i++) {
-        m_digit_button[i] = *find_descendant_of_type_named<GUI::Button>(DeprecatedString::formatted("{}_button", i));
+        m_digit_button[i] = *find_descendant_of_type_named<GUI::Button>(String::formatted("{}_button", i).release_value_but_fixme_should_propagate_errors());
         add_digit_button(*m_digit_button[i], i);
     }
 
@@ -128,9 +128,9 @@ void CalculatorWidget::add_digit_button(GUI::Button& button, int digit)
     };
 }
 
-DeprecatedString CalculatorWidget::get_entry()
+String CalculatorWidget::get_entry()
 {
-    return m_entry->text();
+    return String::from_deprecated_string(m_entry->text()).release_value_but_fixme_should_propagate_errors();
 }
 
 void CalculatorWidget::set_entry(Crypto::BigFraction value)
@@ -147,7 +147,7 @@ void CalculatorWidget::set_typed_entry(Crypto::BigFraction value)
 
 void CalculatorWidget::update_display()
 {
-    m_entry->set_text(m_keypad.to_deprecated_string());
+    m_entry->set_text(m_keypad.to_string().release_value_but_fixme_should_propagate_errors());
     if (m_calculator.has_error())
         m_label->set_text("E"_string);
     else
diff --git a/Userland/Applications/Calculator/CalculatorWidget.h b/Userland/Applications/Calculator/CalculatorWidget.h
index 1333a8581d..603b70d0de 100644
--- a/Userland/Applications/Calculator/CalculatorWidget.h
+++ b/Userland/Applications/Calculator/CalculatorWidget.h
@@ -19,7 +19,7 @@ class CalculatorWidget final : public GUI::Widget {
     C_OBJECT(CalculatorWidget)
 public:
     virtual ~CalculatorWidget() override = default;
-    DeprecatedString get_entry();
+    String get_entry();
     void set_entry(Crypto::BigFraction);
     void set_typed_entry(Crypto::BigFraction);
 
diff --git a/Userland/Applications/Calculator/Keypad.cpp b/Userland/Applications/Calculator/Keypad.cpp
index e8e2c04ad2..df1c1b1751 100644
--- a/Userland/Applications/Calculator/Keypad.cpp
+++ b/Userland/Applications/Calculator/Keypad.cpp
@@ -121,10 +121,10 @@ void Keypad::set_to_0()
     m_state = State::External;
 }
 
-DeprecatedString Keypad::to_deprecated_string() const
+ErrorOr<String> Keypad::to_string() const
 {
     if (m_state == State::External || m_state == State::TypedExternal)
-        return m_internal_value.to_deprecated_string(m_displayed_fraction_length);
+        return String::from_deprecated_string(m_internal_value.to_deprecated_string(m_displayed_fraction_length));
 
     StringBuilder builder;
 
@@ -142,7 +142,7 @@ DeprecatedString Keypad::to_deprecated_string() const
             builder.append(frac_value);
     }
 
-    return builder.to_deprecated_string();
+    return builder.to_string();
 }
 
 bool Keypad::in_typing_state() const
diff --git a/Userland/Applications/Calculator/Keypad.h b/Userland/Applications/Calculator/Keypad.h
index 3ef3be3a9d..a5d860c4b5 100644
--- a/Userland/Applications/Calculator/Keypad.h
+++ b/Userland/Applications/Calculator/Keypad.h
@@ -7,7 +7,7 @@
 
 #pragma once
 
-#include <AK/DeprecatedString.h>
+#include <AK/String.h>
 #include <LibCrypto/BigFraction/BigFraction.h>
 #include <LibCrypto/BigInt/UnsignedBigInteger.h>
 
@@ -34,7 +34,7 @@ public:
     void set_rounding_length(unsigned);
     unsigned rounding_length() const;
 
-    DeprecatedString to_deprecated_string() const;
+    ErrorOr<String> to_string() const;
 
     bool in_typing_state() const;