diff --git a/app/controllers/budget_categories_controller.rb b/app/controllers/budget_categories_controller.rb
index e8cc83e6b..b779a0224 100644
--- a/app/controllers/budget_categories_controller.rb
+++ b/app/controllers/budget_categories_controller.rb
@@ -42,7 +42,7 @@ class BudgetCategoriesController < ApplicationController
     end
 
     def set_budget
-      start_date = Budget.param_to_date(params[:budget_month_year])
+      start_date = Budget.param_to_date(params[:budget_month_year], family: Current.family)
       @budget = Current.family.budgets.find_by(start_date: start_date)
     end
 end
diff --git a/app/controllers/budgets_controller.rb b/app/controllers/budgets_controller.rb
index 9ec26e831..1ec8e81b6 100644
--- a/app/controllers/budgets_controller.rb
+++ b/app/controllers/budgets_controller.rb
@@ -35,7 +35,7 @@ class BudgetsController < ApplicationController
     end
 
     def set_budget
-      start_date = Budget.param_to_date(params[:month_year])
+      start_date = Budget.param_to_date(params[:month_year], family: Current.family)
       @budget = Budget.find_or_bootstrap(Current.family, start_date: start_date)
       raise ActiveRecord::RecordNotFound unless @budget
     end
diff --git a/app/controllers/concerns/periodable.rb b/app/controllers/concerns/periodable.rb
index 8cf02395f..88be0f05c 100644
--- a/app/controllers/concerns/periodable.rb
+++ b/app/controllers/concerns/periodable.rb
@@ -7,7 +7,15 @@ module Periodable
 
   private
     def set_period
-      @period = Period.from_key(params[:period] || Current.user&.default_period)
+      period_key = params[:period] || Current.user&.default_period
+
+      @period = if period_key == "current_month"
+        Period.current_month_for(Current.family)
+      elsif period_key == "last_month"
+        Period.last_month_for(Current.family)
+      else
+        Period.from_key(period_key)
+      end
     rescue Period::InvalidKeyError
       @period = Period.last_30_days
     end
diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index 59fa68bdb..f74c7e6e1 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -106,7 +106,7 @@ class UsersController < ApplicationController
       params.require(:user).permit(
         :first_name, :last_name, :email, :profile_image, :redirect_to, :delete_profile_image, :onboarded_at,
         :show_sidebar, :default_period, :default_account_order, :show_ai_sidebar, :ai_enabled, :theme, :set_onboarding_preferences_at, :set_onboarding_goals_at, :locale,
-        family_attributes: [ :name, :currency, :country, :date_format, :timezone, :locale, :id ],
+        family_attributes: [ :name, :currency, :country, :date_format, :timezone, :locale, :month_start_day, :id ],
         goals: []
       )
     end
diff --git a/app/models/budget.rb b/app/models/budget.rb
index 33f34eb2f..c345801fc 100644
--- a/app/models/budget.rb
+++ b/app/models/budget.rb
@@ -19,24 +19,41 @@ class Budget < ApplicationRecord
       date.strftime(PARAM_DATE_FORMAT).downcase
     end
 
-    def param_to_date(param)
-      Date.strptime(param, PARAM_DATE_FORMAT).beginning_of_month
+    def param_to_date(param, family: nil)
+      base_date = Date.strptime(param, PARAM_DATE_FORMAT)
+      if family&.uses_custom_month_start?
+        Date.new(base_date.year, base_date.month, family.month_start_day)
+      else
+        base_date.beginning_of_month
+      end
     end
 
     def budget_date_valid?(date, family:)
-      beginning_of_month = date.beginning_of_month
-
-      beginning_of_month >= oldest_valid_budget_date(family) && beginning_of_month <= Date.current.end_of_month
+      if family.uses_custom_month_start?
+        budget_start = family.custom_month_start_for(date)
+        budget_start >= oldest_valid_budget_date(family) && budget_start <= family.custom_month_end_for(Date.current)
+      else
+        beginning_of_month = date.beginning_of_month
+        beginning_of_month >= oldest_valid_budget_date(family) && beginning_of_month <= Date.current.end_of_month
+      end
     end
 
     def find_or_bootstrap(family, start_date:)
       return nil unless budget_date_valid?(start_date, family: family)
 
       Budget.transaction do
+        if family.uses_custom_month_start?
+          budget_start = family.custom_month_start_for(start_date)
+          budget_end = family.custom_month_end_for(start_date)
+        else
+          budget_start = start_date.beginning_of_month
+          budget_end = start_date.end_of_month
+        end
+
         budget = Budget.find_or_create_by!(
           family: family,
-          start_date: start_date.beginning_of_month,
-          end_date: start_date.end_of_month
+          start_date: budget_start,
+          end_date: budget_end
         ) do |b|
           b.currency = family.currency
         end
@@ -49,7 +66,6 @@ class Budget < ApplicationRecord
 
     private
       def oldest_valid_budget_date(family)
-        # Allow going back to either the earliest entry date OR 2 years ago, whichever is earlier
         two_years_ago = 2.years.ago.beginning_of_month
         oldest_entry_date = family.oldest_entry_date.beginning_of_month
         [ two_years_ago, oldest_entry_date ].min
@@ -95,7 +111,15 @@ class Budget < ApplicationRecord
   end
 
   def name
-    start_date.strftime("%B %Y")
+    if family.uses_custom_month_start?
+      I18n.t(
+        "budgets.name.custom_range",
+        start: start_date.strftime("%b %d"),
+        end_date: end_date.strftime("%b %d, %Y")
+      )
+    else
+      I18n.t("budgets.name.month_year", month: start_date.strftime("%B %Y"))
+    end
   end
 
   def initialized?
@@ -111,7 +135,12 @@ class Budget < ApplicationRecord
   end
 
   def current?
-    start_date == Date.today.beginning_of_month && end_date == Date.today.end_of_month
+    if family.uses_custom_month_start?
+      current_period = family.current_custom_month_period
+      start_date == current_period.start_date && end_date == current_period.end_date
+    else
+      start_date == Date.current.beginning_of_month && end_date == Date.current.end_of_month
+    end
   end
 
   def previous_budget_param
diff --git a/app/models/family.rb b/app/models/family.rb
index af9f0aa98..6741393ca 100644
--- a/app/models/family.rb
+++ b/app/models/family.rb
@@ -40,6 +40,32 @@ class Family < ApplicationRecord
 
   validates :locale, inclusion: { in: I18n.available_locales.map(&:to_s) }
   validates :date_format, inclusion: { in: DATE_FORMATS.map(&:last) }
+  validates :month_start_day, inclusion: { in: 1..28 }
+
+  def uses_custom_month_start?
+    month_start_day != 1
+  end
+
+  def custom_month_start_for(date)
+    if date.day >= month_start_day
+      Date.new(date.year, date.month, month_start_day)
+    else
+      previous_month = date - 1.month
+      Date.new(previous_month.year, previous_month.month, month_start_day)
+    end
+  end
+
+  def custom_month_end_for(date)
+    start_date = custom_month_start_for(date)
+    next_month_start = start_date + 1.month
+    next_month_start - 1.day
+  end
+
+  def current_custom_month_period
+    start_date = custom_month_start_for(Date.current)
+    end_date = custom_month_end_for(Date.current)
+    Period.custom(start_date: start_date, end_date: end_date)
+  end
 
   def assigned_merchants
     merchant_ids = transactions.where.not(merchant_id: nil).pluck(:merchant_id).uniq
diff --git a/app/models/period.rb b/app/models/period.rb
index 3e369f410..4188478f2 100644
--- a/app/models/period.rb
+++ b/app/models/period.rb
@@ -116,6 +116,22 @@ class Period
     def as_options
       all.map { |period| [ period.label_short, period.key ] }
     end
+
+    def current_month_for(family)
+      return from_key("current_month") unless family&.uses_custom_month_start?
+
+      family.current_custom_month_period
+    end
+
+    def last_month_for(family)
+      return from_key("last_month") unless family&.uses_custom_month_start?
+
+      current_start = family.custom_month_start_for(Date.current)
+      last_month_date = current_start - 1.day
+      start_date = family.custom_month_start_for(last_month_date)
+      end_date = family.custom_month_end_for(last_month_date)
+      custom(start_date: start_date, end_date: end_date)
+    end
   end
 
   PERIODS.each do |key, period|
diff --git a/app/views/settings/preferences/show.html.erb b/app/views/settings/preferences/show.html.erb
index 769b31801..a9f44e029 100644
--- a/app/views/settings/preferences/show.html.erb
+++ b/app/views/settings/preferences/show.html.erb
@@ -40,6 +40,17 @@
             { label: t(".country") },
             { data: { auto_submit_form_target: "auto" } } %>
 
+        <%= family_form.select :month_start_day,
+            (1..28).map { |day| [day.ordinalize, day] },
+            { label: t(".month_start_day"), hint: t(".month_start_day_hint") },
+            { data: { auto_submit_form_target: "auto" } } %>
+
+        <% if @user.family.uses_custom_month_start? %>
+          <div class="text-sm text-warning bg-warning/10 p-3 rounded-lg">
+            <%= t(".month_start_day_warning") %>
+          </div>
+        <% end %>
+
         <p class="text-xs italic pl-2 text-secondary">Please note, we are still working on translations for various languages.</p>
       <% end %>
     <% end %>
diff --git a/config/locales/views/budgets/en.yml b/config/locales/views/budgets/en.yml
new file mode 100644
index 000000000..6f98a5686
--- /dev/null
+++ b/config/locales/views/budgets/en.yml
@@ -0,0 +1,10 @@
+---
+en:
+  budgets:
+    name:
+      custom_range: "%{start} - %{end_date}"
+      month_year: "%{month}"
+    show:
+      tabs:
+        actual: Actual
+        budgeted: Budgeted
diff --git a/config/locales/views/settings/en.yml b/config/locales/views/settings/en.yml
index ca407957b..27d8cee29 100644
--- a/config/locales/views/settings/en.yml
+++ b/config/locales/views/settings/en.yml
@@ -44,6 +44,9 @@ en:
         theme_system: System
         theme_title: Theme
         timezone: Timezone
+        month_start_day: Budget month starts on
+        month_start_day_hint: Set when your budget month starts (e.g., payday)
+        month_start_day_warning: Your budgets and MTD calculations will use this custom start day instead of the 1st of each month.
     profiles:
       destroy:
         cannot_remove_self: You cannot remove yourself from the account.
diff --git a/db/migrate/20260127213817_add_month_start_day_to_families.rb b/db/migrate/20260127213817_add_month_start_day_to_families.rb
new file mode 100644
index 000000000..2b97fe6c6
--- /dev/null
+++ b/db/migrate/20260127213817_add_month_start_day_to_families.rb
@@ -0,0 +1,6 @@
+class AddMonthStartDayToFamilies < ActiveRecord::Migration[7.2]
+  def change
+    add_column :families, :month_start_day, :integer, default: 1, null: false
+    add_check_constraint :families, "month_start_day >= 1 AND month_start_day <= 28", name: "month_start_day_range"
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 3277c7385..873fc72b2 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -499,6 +499,8 @@ ActiveRecord::Schema[7.2].define(version: 2026_01_29_200129) do
     t.datetime "latest_sync_activity_at", default: -> { "CURRENT_TIMESTAMP" }
     t.datetime "latest_sync_completed_at", default: -> { "CURRENT_TIMESTAMP" }
     t.boolean "recurring_transactions_disabled", default: false, null: false
+    t.integer "month_start_day", default: 1, null: false
+    t.check_constraint "month_start_day >= 1 AND month_start_day <= 28", name: "month_start_day_range"
   end
 
   create_table "family_exports", id: :uuid, default: -> { "gen_random_uuid()" }, force: :cascade do |t|
diff --git a/test/models/family/month_start_day_test.rb b/test/models/family/month_start_day_test.rb
new file mode 100644
index 000000000..ca4d3c8a8
--- /dev/null
+++ b/test/models/family/month_start_day_test.rb
@@ -0,0 +1,70 @@
+require "test_helper"
+
+class Family::MonthStartDayTest < ActiveSupport::TestCase
+  setup do
+    @family = families(:dylan_family)
+  end
+
+  test "month_start_day defaults to 1" do
+    assert_equal 1, @family.month_start_day
+  end
+
+  test "validates month_start_day is between 1 and 28" do
+    @family.month_start_day = 0
+    assert_not @family.valid?
+
+    @family.month_start_day = 29
+    assert_not @family.valid?
+
+    @family.month_start_day = 15
+    assert @family.valid?
+  end
+
+  test "uses_custom_month_start? returns false when month_start_day is 1" do
+    @family.month_start_day = 1
+    assert_not @family.uses_custom_month_start?
+  end
+
+  test "uses_custom_month_start? returns true when month_start_day is not 1" do
+    @family.month_start_day = 25
+    assert @family.uses_custom_month_start?
+  end
+
+  test "custom_month_start_for returns correct start date when day is after month_start_day" do
+    @family.month_start_day = 15
+
+    travel_to Date.new(2026, 1, 20) do
+      result = @family.custom_month_start_for(Date.current)
+      assert_equal Date.new(2026, 1, 15), result
+    end
+  end
+
+  test "custom_month_start_for returns correct start date when day is before month_start_day" do
+    @family.month_start_day = 15
+
+    travel_to Date.new(2026, 1, 10) do
+      result = @family.custom_month_start_for(Date.current)
+      assert_equal Date.new(2025, 12, 15), result
+    end
+  end
+
+  test "custom_month_end_for returns one day before next custom month start" do
+    @family.month_start_day = 15
+
+    travel_to Date.new(2026, 1, 20) do
+      result = @family.custom_month_end_for(Date.current)
+      assert_equal Date.new(2026, 2, 14), result
+    end
+  end
+
+  test "current_custom_month_period returns correct period" do
+    @family.month_start_day = 25
+
+    travel_to Date.new(2026, 1, 27) do
+      period = @family.current_custom_month_period
+
+      assert_equal Date.new(2026, 1, 25), period.start_date
+      assert_equal Date.new(2026, 2, 24), period.end_date
+    end
+  end
+end