diff --git a/app/assets/stylesheets/application.css b/app/assets/stylesheets/application.css
index ef20958..77442e2 100644
--- a/app/assets/stylesheets/application.css
+++ b/app/assets/stylesheets/application.css
@@ -49,15 +49,18 @@
 }
 
 
+/* TODO: collapse gaps around empty rows (`topside`) once possible
+ * https://github.com/w3c/csswg-drafts/issues/5813 */
 body {
   display: grid;
   gap: 0.8em;
   grid-template-areas:
-    "header   header  header"
-    "nav      nav     nav"
-    "leftside main    rightside";
+    "header    header  header"
+    "nav       nav     nav"
+    "leftempty topside rightempty"
+    "leftside  main    rightside";
   grid-template-columns: 1fr auto 1fr;
-  grid-template-rows: repeat(3, auto);
+  grid-template-rows: repeat(4, auto);
   font-family: system-ui;
   margin: 0.4em;
 }
@@ -108,12 +111,14 @@ textarea {
 }
 .button,
 button,
+fieldset,
 input,
 select,
 textarea {
   border: solid 1px var(--color-gray);
   border-radius: 0.25em;
 }
+fieldset,
 textarea {
   margin: 0
 }
@@ -124,6 +129,12 @@ button > svg {
   padding-right: 0.4em;
   width: 1.8em;
 }
+fieldset {
+  padding: 0.4em;
+}
+legend {
+  color: var(--color-gray);
+}
 
 /* TODO: move normal non-button links (<a>:hover/:focus) styling here (i.e.
  * page-wide, top-level) and remove from table.items - as the style should be
@@ -230,6 +241,9 @@ header {
 }
 
 
+.topside {
+  grid-area: topside;
+}
 .leftside {
   grid-area: leftside;
 }
@@ -409,8 +423,7 @@ table.items td {
   height: 2.4em;
   padding-block: 0.1em;
 }
-table.items td.actions {
-  align-items: center;
+table.items .actions {
   display: flex;
   gap: 0.4em;
   justify-content: end;
@@ -505,6 +518,17 @@ table.items select:focus-visible {
   color: black;
 }
 
+form table.items {
+  border: none;
+}
+form table.items td {
+  border: none;
+  text-align: left;
+  vertical-align: middle;
+}
+form table.items td:first-child {
+  color: inherit;
+}
 
 .centered {
   margin: 0 auto;
@@ -512,10 +536,15 @@ table.items select:focus-visible {
 .extendedright {
   margin-right: auto;
 }
-.htoolbox {
+.hflex {
   display: flex;
   gap: 0.8em;
 }
+.vflex {
+  display: flex;
+  gap: 0.8em;
+  flex-direction: column;
+}
 [disabled] {
   border-color: var(--color-border-gray) !important;
   color: var(--color-border-gray) !important;
diff --git a/app/controllers/measurements_controller.rb b/app/controllers/measurements_controller.rb
index 1980b22..0ef5763 100644
--- a/app/controllers/measurements_controller.rb
+++ b/app/controllers/measurements_controller.rb
@@ -1,9 +1,31 @@
 class MeasurementsController < ApplicationController
+  before_action :find_quantity, only: [:new]
+
   def index
     @quantities = current_user.quantities.ordered
   end
 
   def new
+    readouts_params = params.permit(user: [readouts_attributes: Readout::ATTRIBUTES])
+    build_attrs = readouts_params.dig(:user, :readouts_attributes)&.values
+    prev_readouts = build_attrs ? Array(current_user.readouts.build(build_attrs)) : []
+
+    quantities =
+      case params[:scope]
+      when 'children'
+        @quantity.subquantities
+      when 'subtree'
+        @quantity.progenies
+      else
+        [@quantity]
+      end
+    quantities -= prev_readouts.map(&:quantity)
+    new_readouts = current_user.readouts.build(quantities.map { |q| {quantity: q} })
+    @readouts = prev_readouts + new_readouts
+
+    @ancestor_fullname = current_user.quantities
+      .common_ancestors(@readouts.map { |r| r.quantity.parent_id }).first&.fullname || ''
+    @units = current_user.units.ordered
   end
 
   def create
@@ -11,4 +33,10 @@ class MeasurementsController < ApplicationController
 
   def destroy
   end
+
+  private
+
+  def find_quantity
+    @quantity = current_user.quantities.find_by!(id: params[:id])
+  end
 end
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index bdd8e8f..4d06158 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -104,11 +104,12 @@ module ApplicationHelper
   end
 
   def tabular_fields_for(record_name, record_object = nil, options = {}, &block)
-    # skip_default_ids causes turbo to generate unique ID for element with [autofocus].
-    # Otherwise IDs are not unique when multiple forms are open and the first input gets focus.
+    # skip_default_ids causes turbo to generate unique ID for element with
+    # [autofocus].  Otherwise IDs are not unique when multiple forms are open
+    # and the first input gets focus.
     record_object, options = nil, record_object if record_object.is_a? Hash
     options.merge! builder: TabularFormBuilder, skip_default_ids: true
-    render_errors(record_name)
+    render_errors(record_object || record_name)
     fields_for(record_name, record_object, **options, &block)
   end
 
@@ -169,8 +170,9 @@ module ApplicationHelper
     link_to name, options, html_options
   end
 
-  def render_errors(record)
-    flash.now[:alert] = record.errors.full_messages unless record.errors.empty?
+  def render_errors(records)
+    flash[:alert] ||= []
+    Array(records).each { |record| flash[:alert] += record.errors.full_messages }
   end
 
   def render_flash_messages
diff --git a/app/models/quantity.rb b/app/models/quantity.rb
index ffc5086..604d3f5 100644
--- a/app/models/quantity.rb
+++ b/app/models/quantity.rb
@@ -61,17 +61,20 @@ class Quantity < ApplicationRecord
   scope :defaults, ->{ where(user: nil) }
 
   # Return: ordered [sub]hierarchy
-  scope :ordered, ->(root: nil) {
+  scope :ordered, ->(root: nil, include_root: true) {
     numbered = Arel::Table.new('numbered')
 
     self.model.with(numbered: numbered(:parent_id, :name)).with_recursive(arel_table.name => [
       numbered.project(
         numbered[Arel.star],
         numbered.cast(numbered[:child_number], 'BINARY').as('path'),
-      ).where(numbered[root ? :id : :parent_id].eq(root)),
+        numbered.cast(numbered[:name], 'CHAR(512)').as('fullname')
+      ).where(numbered[root && include_root ? :id : :parent_id].eq(root)),
       numbered.project(
         numbered[Arel.star],
         arel_table[:path].concat(numbered[:child_number]),
+        arel_table[:fullname].concat(Arel::Nodes.build_quoted(' → '))
+          .concat(numbered[:name]),
       ).join(arel_table).on(numbered[:parent_id].eq(arel_table[:id]))
     ]).order(arel_table[:path])
   }
@@ -109,6 +112,23 @@ class Quantity < ApplicationRecord
     parent_id.nil?
   end
 
+  # Common ancestors, assuming node is a descendant of itself
+  scope :common_ancestors, ->(of) {
+    selected = Arel::Table.new('selected')
+
+    # Take unique IDs, so self can be called with parent nodes of collection to
+    # get common ancestors of collection _excluding_ nodes in collection.
+    uniq_of = of.uniq
+    model.with(selected: self).with_recursive(arel_table.name => [
+      selected.project(selected[Arel.star]).where(selected[:id].in(uniq_of)),
+      selected.project(selected[Arel.star])
+        .join(arel_table).on(selected[:id].eq(arel_table[:parent_id]))
+    ]).select(arel_table[Arel.star])
+      .group(column_names)
+      .having(arel_table[:id].count.eq(uniq_of.size))
+      .order(arel_table[:depth].desc)
+  }
+
   # Return: successive record in order of appearance; used for partial view reload
   def successive
     quantities = Quantity.arel_table
@@ -124,6 +144,10 @@ class Quantity < ApplicationRecord
     user.quantities.ordered(root: id).to_a
   end
 
+  def progenies
+    user.quantities.ordered(root: id, include_root: false).to_a
+  end
+
   # Return: record with ID `of` with its ancestors, sorted by `depth`
   scope :with_ancestors, ->(of) {
     selected = Arel::Table.new('selected')
@@ -143,4 +167,9 @@ class Quantity < ApplicationRecord
   def ancestor_of?(progeny)
     user.quantities.with_ancestors(progeny.id).exists?(id)
   end
+
+  def fullname
+    self['fullname'] ||
+      user.quantities.with_ancestors(id).order(:depth).map(&:name).join(' → ')
+  end
 end
diff --git a/app/models/readout.rb b/app/models/readout.rb
index f8855be..f50037c 100644
--- a/app/models/readout.rb
+++ b/app/models/readout.rb
@@ -1,4 +1,6 @@
 class Readout < ApplicationRecord
+  ATTRIBUTES = [:quantity_id, :value, :unit_id]
+
   belongs_to :user
   belongs_to :quantity
   belongs_to :unit
diff --git a/app/models/user.rb b/app/models/user.rb
index 0ef2ba3..d76568b 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -11,6 +11,8 @@ class User < ApplicationRecord
     disabled: 0,    # administratively disallowed to sign in
   }, default: :active
 
+  has_many :readouts, dependent: :destroy
+  accepts_nested_attributes_for :readouts
   has_many :quantities, dependent: :destroy
   has_many :units, dependent: :destroy
 
diff --git a/app/views/layouts/application.html.erb b/app/views/layouts/application.html.erb
index 2e89934..762b5a5 100644
--- a/app/views/layouts/application.html.erb
+++ b/app/views/layouts/application.html.erb
@@ -23,7 +23,7 @@
   </head>
 
   <body>
-    <header class="htoolbox">
+    <header class="hflex">
       <%= image_link_to t(".source_code"), "code-braces", source_code_url %>
       <%= image_link_to t(".issue_tracker"), "bug-outline", issue_tracker_url,
             class: "extendedright" %>
diff --git a/app/views/measurements/_form.html.erb b/app/views/measurements/_form.html.erb
new file mode 100644
index 0000000..dcd4ff0
--- /dev/null
+++ b/app/views/measurements/_form.html.erb
@@ -0,0 +1,45 @@
+<%= tabular_form_with model: current_user, html: {id: :new_readouts_form} do |user| %>
+  <% if @readouts&.present? %>
+    <fieldset>
+      <%= tag.legend @ancestor_fullname unless @ancestor_fullname.empty? %>
+      <table class="items centered">
+        <tbody id="readouts">
+          <%= user.fields_for :readouts, @readouts do |form| %>
+            <% row = dom_id(form.object.quantity, :new, :readout) %>
+            <%- tag.tr id: row, onkeydown: 'processKey(event)' do %>
+              <td>
+                <%= form.object.quantity.fullname.delete_prefix(@ancestor_fullname) %>
+                <%= form.hidden_field :quantity_id %>
+              </td>
+              <td>
+                <%= form.number_field :value, required: true, autofocus: true,
+                  size: 10 %>
+              </td>
+              <td>
+                <%= form.select :unit_id, options_from_collection_for_select(
+                  @units, :id, ->(u){ sanitize('&emsp;'*(u.base_id ? 1 : 0) + u.symbol) }
+                ) %>
+              </td>
+
+              <td class="actions">
+                <%= image_link_to t(:delete), 'delete-outline', quantities_path,
+                  class: 'dangerous',
+                  onclick: render_turbo_stream('form_destroy_row', {row: row}) %>
+              </td>
+            <% end %>
+          <% end %>
+          <tr id="new_readouts_actions">
+            <td></td>
+            <td></td>
+            <td><div class="actions"><%= user.button %></div></td>
+            <td><div class="actions">
+              <%= image_link_to t(:cancel), "close-outline", measurements_path,
+                class: 'dangerous', name: :cancel,
+                onclick: render_turbo_stream('form_close') %>
+            </div></td>
+          </tr>
+        </tbody>
+      </table>
+    </fieldset>
+  <% end %>
+<% end %>
diff --git a/app/views/measurements/_form_close.html.erb b/app/views/measurements/_form_close.html.erb
new file mode 100644
index 0000000..a171e26
--- /dev/null
+++ b/app/views/measurements/_form_close.html.erb
@@ -0,0 +1,2 @@
+<%= turbo_stream.update :new_readouts_form %>
+<%= turbo_stream.update :flashes %>
diff --git a/app/views/measurements/_form_destroy_row.html.erb b/app/views/measurements/_form_destroy_row.html.erb
new file mode 100644
index 0000000..f567f95
--- /dev/null
+++ b/app/views/measurements/_form_destroy_row.html.erb
@@ -0,0 +1,2 @@
+<%= turbo_stream.remove row %>
+<%= turbo_stream.update :flashes %>
diff --git a/app/views/measurements/index.html.erb b/app/views/measurements/index.html.erb
index 165101b..9d5aec4 100644
--- a/app/views/measurements/index.html.erb
+++ b/app/views/measurements/index.html.erb
@@ -1,16 +1,20 @@
-<div class="main">
+<div class="topside vflex">
   <% if current_user.at_least(:active) %>
+    <%= render partial: 'form' %>
     <%# TODO: show hint when no quantities/units defined %>
-    <%= form_tag new_measurement_path, method: :get, class: "htoolbox",
-      data: {turbo_stream: true} do %>
-      <%= select_tag :id,
-        options_from_collection_for_select(@quantities, :id,
-                                           ->(q) { sanitize('-&nbsp;'*q.depth + q.name) }) %>
-      <%= image_button_tag t('.new_quantity'), 'plus-outline', name: :scope -%>
+    <div class="hflex">
+      <%= select_tag :id, options_from_collection_for_select(
+        @quantities, :id, ->(q){ sanitize('&emsp;'*q.depth + q.name) }
+      ), form: :new_readouts_form %>
+      <% common_options = {form: :new_readouts_form, formaction: new_measurement_path,
+                           formmethod: :get, formnovalidate: true,
+                           data: {turbo_stream: true}} %>
+      <%= image_button_tag t('.new_quantity'), 'plus-outline', name: :scope,
+        **common_options -%>
       <%= image_button_tag t('.new_children'), 'plus-multiple-outline', name: :scope,
-        value: :children -%>
+        value: :children, **common_options -%>
       <%= image_button_tag t('.new_subtree'), 'plus-multiple-outline', name: :scope,
-        value: :subtree -%>
-    <% end %>
+        value: :subtree, **common_options -%>
+    </div>
   <% end %>
 </div>
diff --git a/app/views/measurements/new.turbo_stream.erb b/app/views/measurements/new.turbo_stream.erb
new file mode 100644
index 0000000..4c3a55c
--- /dev/null
+++ b/app/views/measurements/new.turbo_stream.erb
@@ -0,0 +1,3 @@
+<%= turbo_stream.replace :new_readouts_form, method: :morph do %>
+  <%= render partial: 'form' %>
+<% end %>
diff --git a/app/views/quantities/index.html.erb b/app/views/quantities/index.html.erb
index 6b0d909..0ed1454 100644
--- a/app/views/quantities/index.html.erb
+++ b/app/views/quantities/index.html.erb
@@ -7,7 +7,7 @@
     class: 'tools' %>
 </div>
 
-<%= tag.div id: :quantity_form %>
+<%= tag.div class: 'main', id: :quantity_form %>
 
 <table class="main items">
   <thead>
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 7ad730d..bee1caa 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -151,6 +151,7 @@ en:
   add: Add
   back: Back
   cancel: Cancel
+  delete: Delete
   or: or
   register: Register
   sign_in: Sign in