diff --git a/src/components/inputs/FrequencyInput.svelte b/src/components/inputs/FrequencyInput.svelte
index ba96034..5fd457d 100644
--- a/src/components/inputs/FrequencyInput.svelte
+++ b/src/components/inputs/FrequencyInput.svelte
@@ -2,6 +2,8 @@
 	import DateInputs from './DateInputs.svelte';
 
 	export let selectedFrequency = '1-month';
+	export let interval = null;
+	export let unitOfMeasurement = null;
 	export let daysOfMonth = [];
 	export let date;
 </script>
@@ -86,6 +88,17 @@
 			/>
 			<label for="frequency__twice-per-month">Twice per Month</label>
 		</div>
+		<div>
+			<input
+				id="frequency__custom"
+				type="radio"
+				name="frequency"
+				value="custom"
+				bind:group={selectedFrequency}
+				class="cmp-form__radio-input"
+			/>
+			<label for="frequency__custom">Custom</label>
+		</div>
 	</div>
 </fieldset>
 
@@ -111,6 +124,58 @@
 			{/each}
 		</div>
 	</fieldset>
+{:else if selectedFrequency === 'custom'}
+	<div>
+		<label for="interval" class="cmp-form__label">Interval</label>
+		<input
+			id="interval"
+			type="text"
+			name="interval"
+			value={interval}
+			class="cmp-form__input cmp-form__input--short"
+			inputmode="numeric"
+			pattern="^(0|[1-9]\d*)$"
+		/>
+	</div>
+	<fieldset class="cmp-form__fieldset">
+		<legend class="cmp-form__legend">Unit of measurement</legend>
+		<div class="cmp-form__radios">
+			<div>
+				<input
+					id="interval__days"
+					type="radio"
+					name="unitOfMeasurement"
+					value="day"
+					bind:group={unitOfMeasurement}
+					class="cmp-form__radio-input"
+				/>
+				<label for="interval__days">Days</label>
+			</div>
+			<div>
+				<input
+					id="interval__weeks"
+					type="radio"
+					name="unitOfMeasurement"
+					value="week"
+					bind:group={unitOfMeasurement}
+					class="cmp-form__radio-input"
+				/>
+				<label for="interval__weeks">Weeks</label>
+			</div>
+			<div>
+				<input
+					id="interval__months"
+					type="radio"
+					name="unitOfMeasurement"
+					value="month"
+					bind:group={unitOfMeasurement}
+					class="cmp-form__radio-input"
+				/>
+				<label for="interval__months">Months</label>
+			</div>
+		</div>
+	</fieldset>
+	<DateInputs legend="Choose the most recent date when this expense occurred" {date} />
 {:else}
 	<DateInputs legend="Choose the most recent date when this expense occurred" {date} />
 {/if}
diff --git a/src/lib/copy-recurring.js b/src/lib/copy-recurring.js
index 237e0a1..7ab654a 100644
--- a/src/lib/copy-recurring.js
+++ b/src/lib/copy-recurring.js
@@ -138,6 +138,53 @@ const copyRecurring =
 					break;
 				}
 				default: {
+					const gapInDays = Math.floor((currentMonth - originalDate) / 1000 / 3600 / 24);
+					const [interval, unitOfMeasurement] = entry.frequency.split('-');
+					let numberOfDays = 0;
+					let numberOfMonths = 0;
+					switch (unitOfMeasurement) {
+						case 'day':
+							numberOfDays = Number.parseInt(interval, 10);
+							break;
+						case 'week':
+							numberOfDays = Number.parseInt(interval, 10) * 7;
+							break;
+						case 'month':
+							numberOfMonths = Number.parseInt(interval, 10);
+							break;
+						default:
+							break;
+					}
+					if (numberOfDays === 0 && numberOfMonths === 0) {
+						break;
+					}
+
+					let newEntryDate = new Date(numericYear, numericMonth, originalDateDay);
+					if (numberOfDays > 0) {
+						const offset = numberOfDays - (gapInDays % numberOfDays);
+						newEntryDate = new Date(numericYear, numericMonth, 1 + offset);
+					} else if (numberOfMonths > 0) {
+						newEntryDate = new Date(
+							numericYear,
+							originalDateMonth + numberOfMonths,
+							originalDateDay
+						);
+					}
+
+					while (newEntryDate < nextMonth) {
+						const newEntry = {
+							...entry,
+							date: new Date(newEntryDate),
+						};
+						delete newEntry.frequency;
+						delete newEntry.days_of_month;
+						newEntries.push(newEntry);
+						if (numberOfDays > 0) {
+							newEntryDate.setDate(newEntryDate.getDate() + numberOfDays);
+						} else {
+							newEntryDate.setDate(newEntryDate.getDate() + numberOfMonths * 31);
+						}
+					}
 					break;
 				}
 			}
diff --git a/src/lib/format-recurring.js b/src/lib/format-recurring.js
index 11b6bd8..bb8ed86 100644
--- a/src/lib/format-recurring.js
+++ b/src/lib/format-recurring.js
@@ -1,3 +1,19 @@
+import { formatDate, formatAmount } from '$lib/format-inputs';
+
+const customAnnualMultiplier = (frequency) => {
+	const [interval, unitOfMeasurement] = frequency.split('-');
+	switch (unitOfMeasurement) {
+		case 'day':
+			return 365 / Number.parseInt(interval, 10);
+		case 'week':
+			return 52 / Number.parseInt(interval, 10);
+		case 'month':
+			return 12 / Number.parseInt(interval, 10);
+		default:
+			return 1;
+	}
+};
+
 export const annualAmount = ({ frequency, amount }) => {
 	switch (frequency) {
 		case '1-month':
@@ -15,10 +31,15 @@ export const annualAmount = ({ frequency, amount }) => {
 		case 'twice-per-month':
 			return amount * 24;
 		default:
-			return 0;
+			return amount * customAnnualMultiplier(frequency);
 	}
 };
 
+const customFrequencyDescription = (frequency) => {
+	const [interval, unitOfMeasurement] = frequency.split('-');
+	return `/${interval} ${unitOfMeasurement}${unitOfMeasurement !== '1' ? 's' : ''}`;
+};
+
 export const formatFrequency = (frequency) => {
 	switch (frequency) {
 		case '1-month':
@@ -36,6 +57,67 @@ export const formatFrequency = (frequency) => {
 		case 'twice-per-month':
 			return ' twice per month';
 		default:
-			return '';
+			return customFrequencyDescription(frequency);
 	}
 };
+
+export const getRecurringEntryFormData = (formData) => {
+	const amount = formatAmount(formData.get('amount'));
+
+	const selectedCategory = formData.get('category');
+	const newCategory = formData.get('new-category');
+	const category = newCategory ?? selectedCategory;
+
+	const description = formData.get('description') || category;
+
+	const now = new Date();
+	const year = formData.get('year') ?? now.getFullYear();
+	const month = formData.get('month') ?? now.getMonth() + 1;
+	const day = formData.get('day') ?? now.getDate();
+	const date = formatDate(year, month, day);
+
+	const frequency = formData.get('frequency');
+	const interval = formData.get('interval');
+	const unitOfMeasurement = formData.get('unitOfMeasurement');
+	const days_of_month = formData.getAll('days-of-month') ?? [];
+	const active = !!formData.get('active');
+
+	return {
+		amount,
+		category,
+		description,
+		date,
+		frequency: frequency === 'custom' ? `${interval}-${unitOfMeasurement}` : frequency,
+		days_of_month,
+		active,
+	};
+};
+
+export const formatEntry = (entry) => {
+	let { frequency } = entry;
+
+	let interval = null;
+	let unitOfMeasurement = null;
+
+	switch (frequency) {
+		case '1-month':
+		case '3-month':
+		case '6-month':
+		case '1-year':
+		case '1-week':
+		case '2-week':
+		case 'twice-per-month':
+			break;
+		default:
+			[interval, unitOfMeasurement] = frequency.split('-');
+			frequency = 'custom';
+			break;
+	}
+
+	return {
+		...entry,
+		frequency,
+		interval,
+		unitOfMeasurement,
+	};
+};
diff --git a/src/routes/recurring-expenses/expense/+page.server.js b/src/routes/recurring-expenses/expense/+page.server.js
index e6009d6..a1eb745 100644
--- a/src/routes/recurring-expenses/expense/+page.server.js
+++ b/src/routes/recurring-expenses/expense/+page.server.js
@@ -1,5 +1,5 @@
 import { fail, redirect } from '@sveltejs/kit';
-import { formatAmount, formatDate } from '$lib/format-inputs.js';
+import { getRecurringEntryFormData } from '$lib/format-recurring.js';
 import { gateDynamicPage } from '$lib/gate-dynamic-page.js';
 
 export const load = async ({ locals: { supabase } }) => {
@@ -19,23 +19,8 @@ export const load = async ({ locals: { supabase } }) => {
 export const actions = {
 	default: async ({ request, locals: { supabase } }) => {
 		const formData = await request.formData();
-		const amount = formatAmount(formData.get('amount'));
-
-		const selectedCategory = formData.get('category');
-		const newCategory = formData.get('new-category');
-		const category = newCategory ?? selectedCategory;
-
-		const description = formData.get('description') || category;
-
-		const now = new Date();
-		const year = formData.get('year') ?? now.getFullYear();
-		const month = formData.get('month') ?? now.getMonth() + 1;
-		const day = formData.get('day') ?? now.getDate();
-		const date = formatDate(year, month, day);
-
-		const frequency = formData.get('frequency');
-		const days_of_month = formData.getAll('days-of-month') ?? [];
-		const active = !!formData.get('active');
+		const { amount, category, description, date, frequency, days_of_month, active } =
+			getRecurringEntryFormData(formData);
 
 		const {
 			data: { user },
diff --git a/src/routes/recurring-expenses/expense/[id]/+page.server.js b/src/routes/recurring-expenses/expense/[id]/+page.server.js
index b076024..e3e4a18 100644
--- a/src/routes/recurring-expenses/expense/[id]/+page.server.js
+++ b/src/routes/recurring-expenses/expense/[id]/+page.server.js
@@ -1,5 +1,5 @@
 import { fail, redirect } from '@sveltejs/kit';
-import { formatAmount, formatDate } from '$lib/format-inputs.js';
+import { getRecurringEntryFormData, formatEntry } from '$lib/format-recurring.js';
 import { gateDynamicPage } from '$lib/gate-dynamic-page.js';
 
 const getCategories = async (supabase) => {
@@ -21,7 +21,7 @@ const getExpense = async (supabase, id) => {
 		throw new Error('Could not find the specified expense.');
 	}
 
-	return expense[0];
+	return formatEntry(expense[0]);
 };
 
 export const load = async ({ params: { id }, locals: { supabase } }) => {
@@ -44,23 +44,8 @@ export const actions = {
 		const formData = await request.formData();
 		const id = formData.get('id');
 
-		const amount = formatAmount(formData.get('amount'));
-
-		const selectedCategory = formData.get('category');
-		const newCategory = formData.get('new-category');
-		const category = newCategory ?? selectedCategory;
-
-		const description = formData.get('description') || category;
-
-		const now = new Date();
-		const year = formData.get('year') ?? now.getFullYear();
-		const month = formData.get('month') ?? now.getMonth() + 1;
-		const day = formData.get('day') ?? now.getDate();
-		const date = formatDate(year, month, day);
-
-		const frequency = formData.get('frequency');
-		const days_of_month = formData.getAll('days-of-month') ?? [];
-		const active = !!formData.get('active');
+		const { amount, category, description, date, frequency, days_of_month, active } =
+			getRecurringEntryFormData(formData);
 
 		const updated_at = new Date();
 
diff --git a/src/routes/recurring-expenses/expense/[id]/+page.svelte b/src/routes/recurring-expenses/expense/[id]/+page.svelte
index 9f7f950..d030825 100644
--- a/src/routes/recurring-expenses/expense/[id]/+page.svelte
+++ b/src/routes/recurring-expenses/expense/[id]/+page.svelte
@@ -17,6 +17,8 @@
 	<AmountInput amount={data.expense.amount} />
 	<FrequencyInput
 		selectedFrequency={data.expense.frequency}
+		interval={data.expense.interval}
+		unitOfMeasurement={data.expense.unitOfMeasurement}
 		daysOfMonth={data.expense.days_of_month}
 		date={data.expense.date}
 	/>
diff --git a/src/routes/recurring-income/income/+page.server.js b/src/routes/recurring-income/income/+page.server.js
index 98ccab1..e77a62b 100644
--- a/src/routes/recurring-income/income/+page.server.js
+++ b/src/routes/recurring-income/income/+page.server.js
@@ -1,5 +1,5 @@
 import { fail, redirect } from '@sveltejs/kit';
-import { formatAmount, formatDate } from '$lib/format-inputs.js';
+import { getRecurringEntryFormData } from '$lib/format-recurring.js';
 import { gateDynamicPage } from '$lib/gate-dynamic-page.js';
 
 export const load = async ({ locals: { supabase } }) => {
@@ -19,23 +19,8 @@ export const load = async ({ locals: { supabase } }) => {
 export const actions = {
 	default: async ({ request, locals: { supabase } }) => {
 		const formData = await request.formData();
-		const amount = formatAmount(formData.get('amount'));
-
-		const selectedCategory = formData.get('category');
-		const newCategory = formData.get('new-category');
-		const category = newCategory ?? selectedCategory;
-
-		const description = formData.get('description') || category;
-
-		const now = new Date();
-		const year = formData.get('year') ?? now.getFullYear();
-		const month = formData.get('month') ?? now.getMonth() + 1;
-		const day = formData.get('day') ?? now.getDate();
-		const date = formatDate(year, month, day);
-
-		const frequency = formData.get('frequency');
-		const days_of_month = formData.getAll('days-of-month') ?? [];
-		const active = !!formData.get('active');
+		const { amount, category, description, date, frequency, days_of_month, active } =
+			getRecurringEntryFormData(formData);
 
 		const {
 			data: { user },
diff --git a/src/routes/recurring-income/income/[id]/+page.server.js b/src/routes/recurring-income/income/[id]/+page.server.js
index c5cd194..fa786c0 100644
--- a/src/routes/recurring-income/income/[id]/+page.server.js
+++ b/src/routes/recurring-income/income/[id]/+page.server.js
@@ -1,5 +1,5 @@
 import { fail, redirect } from '@sveltejs/kit';
-import { formatAmount, formatDate } from '$lib/format-inputs.js';
+import { getRecurringEntryFormData, formatEntry } from '$lib/format-recurring.js';
 import { gateDynamicPage } from '$lib/gate-dynamic-page.js';
 
 const getCategories = async (supabase) => {
@@ -21,7 +21,7 @@ const getIncome = async (supabase, id) => {
 		throw new Error('Could not find the specified income.');
 	}
 
-	return income[0];
+	return formatEntry(income[0]);
 };
 
 export const load = async ({ params: { id }, locals: { supabase } }) => {
@@ -44,23 +44,8 @@ export const actions = {
 		const formData = await request.formData();
 		const id = formData.get('id');
 
-		const amount = formatAmount(formData.get('amount'));
-
-		const selectedCategory = formData.get('category');
-		const newCategory = formData.get('new-category');
-		const category = newCategory ?? selectedCategory;
-
-		const description = formData.get('description') || category;
-
-		const now = new Date();
-		const year = formData.get('year') ?? now.getFullYear();
-		const month = formData.get('month') ?? now.getMonth() + 1;
-		const day = formData.get('day') ?? now.getDate();
-		const date = formatDate(year, month, day);
-
-		const frequency = formData.get('frequency');
-		const days_of_month = formData.getAll('days-of-month') ?? [];
-		const active = !!formData.get('active');
+		const { amount, category, description, date, frequency, days_of_month, active } =
+			getRecurringEntryFormData(formData);
 
 		const updated_at = new Date();
 
diff --git a/src/routes/recurring-income/income/[id]/+page.svelte b/src/routes/recurring-income/income/[id]/+page.svelte
index dd6a5a6..025cfc9 100644
--- a/src/routes/recurring-income/income/[id]/+page.svelte
+++ b/src/routes/recurring-income/income/[id]/+page.svelte
@@ -17,6 +17,8 @@
 	<AmountInput amount={data.income.amount} />
 	<FrequencyInput
 		selectedFrequency={data.income.frequency}
+		interval={data.income.interval}
+		unitOfMeasurement={data.income.unitOfMeasurement}
 		daysOfMonth={data.income.days_of_month}
 		date={data.income.date}
 	/>