diff --git a/src/features/budgets/actions.ts b/src/features/budgets/actions.ts
index aa9e9f0..88d67a4 100644
--- a/src/features/budgets/actions.ts
+++ b/src/features/budgets/actions.ts
@@ -3,6 +3,10 @@
 import { and, eq } from "drizzle-orm";
 import { z } from "zod";
 import { budgets, categories } from "@/db/schema";
+import {
+	type CategoryBudgetSummary,
+	fetchCategoryBudgetSummary,
+} from "@/features/budgets/queries";
 import {
 	handleActionError,
 	revalidateForEntity,
@@ -204,6 +208,34 @@ export async function deleteBudgetAction(
 	}
 }
 
+const getCategoryBudgetSummarySchema = z.object({
+	categoryId: uuidSchema("Category"),
+	period: periodSchema,
+});
+
+type GetCategoryBudgetSummaryInput = z.input<
+	typeof getCategoryBudgetSummarySchema
+>;
+
+export async function getCategoryBudgetSummaryAction(
+	input: GetCategoryBudgetSummaryInput,
+): Promise<ActionResult<CategoryBudgetSummary | null>> {
+	try {
+		const user = await getUser();
+		const data = getCategoryBudgetSummarySchema.parse(input);
+		const summary = await fetchCategoryBudgetSummary(
+			user.id,
+			data.categoryId,
+			data.period,
+		);
+		return { success: true, message: "ok", data: summary };
+	} catch (error) {
+		return handleActionError(
+			error,
+		) as ActionResult<CategoryBudgetSummary | null>;
+	}
+}
+
 const duplicatePreviousMonthSchema = z.object({
 	period: periodSchema,
 });
diff --git a/src/features/transactions/components/dialogs/transaction-dialog/category-section.tsx b/src/features/transactions/components/dialogs/transaction-dialog/category-section.tsx
index b253b85..347b6d5 100644
--- a/src/features/transactions/components/dialogs/transaction-dialog/category-section.tsx
+++ b/src/features/transactions/components/dialogs/transaction-dialog/category-section.tsx
@@ -1,5 +1,8 @@
 "use client";
 
+import { useEffect, useRef, useState } from "react";
+import { getCategoryBudgetSummaryAction } from "@/features/budgets/actions";
+import type { CategoryBudgetSummary } from "@/features/budgets/queries";
 import { TRANSACTION_TYPES } from "@/features/transactions/lib/constants";
 import { Label } from "@/shared/components/ui/label";
 import {
@@ -11,6 +14,7 @@ import {
 	SelectTrigger,
 	SelectValue,
 } from "@/shared/components/ui/select";
+import { formatCurrency } from "@/shared/utils/currency";
 import { cn } from "@/shared/utils/ui";
 import {
 	CategorySelectContent,
@@ -18,6 +22,22 @@ import {
 } from "../../select-items";
 import type { CategorySectionProps } from "./transaction-dialog-types";
 
+const BUDGET_DANGER_RATIO = 1;
+const BUDGET_WARNING_RATIO = 0.8;
+
+const getBudgetTone = (ratio: number) => {
+	if (ratio >= BUDGET_DANGER_RATIO) return "text-red-600 dark:text-red-400";
+	if (ratio >= BUDGET_WARNING_RATIO)
+		return "text-amber-600 dark:text-amber-400";
+	return "text-emerald-600 dark:text-emerald-400";
+};
+
+const formatCompactCurrency = (value: number) =>
+	formatCurrency(value, {
+		minimumFractionDigits: 0,
+		maximumFractionDigits: 0,
+	});
+
 export function CategorySection({
 	formState,
 	onFieldChange,
@@ -28,6 +48,62 @@ export function CategorySection({
 }: CategorySectionProps) {
 	const showTransactionTypeField = !isUpdateMode && !hideTransactionType;
 
+	const [budgetSummary, setBudgetSummary] =
+		useState<CategoryBudgetSummary | null>(null);
+	const cacheRef = useRef<Map<string, CategoryBudgetSummary | null>>(new Map());
+
+	const { categoryId, period, transactionType } = formState;
+	const shouldFetchBudget =
+		Boolean(categoryId) && Boolean(period) && transactionType === "Despesa";
+
+	useEffect(() => {
+		if (!shouldFetchBudget || !categoryId || !period) {
+			setBudgetSummary(null);
+			return;
+		}
+
+		const key = `${categoryId}::${period}`;
+		const cached = cacheRef.current.get(key);
+		if (cached !== undefined) {
+			setBudgetSummary((prev) => (prev === cached ? prev : cached));
+			return;
+		}
+
+		let cancelled = false;
+		getCategoryBudgetSummaryAction({ categoryId, period }).then((result) => {
+			if (cancelled) return;
+			const data = result.success ? (result.data ?? null) : null;
+			cacheRef.current.set(key, data);
+			setBudgetSummary(data);
+		});
+
+		return () => {
+			cancelled = true;
+		};
+	}, [shouldFetchBudget, categoryId, period]);
+
+	const renderBudgetBadge = () => {
+		if (showTransactionTypeField) return null;
+		if (!shouldFetchBudget || !budgetSummary) return null;
+
+		const { amount, spent } = budgetSummary;
+		const ratio = amount > 0 ? spent / amount : 0;
+		const percent = amount > 0 ? Math.round(ratio * 100) : 0;
+
+		return (
+			<span
+				title={`${formatCurrency(spent)} de ${formatCurrency(amount)} (${percent}%)`}
+				className={cn(
+					"shrink-0 text-xs font-semibold leading-none whitespace-nowrap font-mono",
+					getBudgetTone(ratio),
+				)}
+			>
+				{formatCompactCurrency(spent)} de {formatCompactCurrency(amount)}
+				<span className="ml-1 opacity-70">({percent}%)</span>
+			</span>
+		);
+	};
+
 	return (
 		<div className="flex w-full flex-col gap-2 md:flex-row">
 			{showTransactionTypeField ? (
@@ -77,12 +153,16 @@ export function CategorySection({
 									const selectedOption = categoryOptions.find(
 										(opt) => opt.value === formState.categoryId,
 									);
-									return selectedOption ? (
-										<CategorySelectContent
-											label={selectedOption.label}
-											icon={selectedOption.icon}
-										/>
-									) : null;
+									if (!selectedOption) return null;
+									return (
+										<span className="flex items-center gap-2">
+											<CategorySelectContent
+												label={selectedOption.label}
+												icon={selectedOption.icon}
+											/>
+											{renderBudgetBadge()}
+										</span>
+									);
 								})()}
 						</SelectValue>
 					</SelectTrigger>
diff --git a/src/features/transactions/components/dialogs/transaction-dialog/payer-section.tsx b/src/features/transactions/components/dialogs/transaction-dialog/payer-section.tsx
index 476d861..ab4928e 100644
--- a/src/features/transactions/components/dialogs/transaction-dialog/payer-section.tsx
+++ b/src/features/transactions/components/dialogs/transaction-dialog/payer-section.tsx
@@ -2,7 +2,9 @@
 
 import * as CheckboxPrimitive from "@radix-ui/react-checkbox";
 import { RiSliceFill } from "@remixicon/react";
+import { useState } from "react";
 import { CurrencyInput } from "@/shared/components/ui/currency-input";
+import { Input } from "@/shared/components/ui/input";
 import { Label } from "@/shared/components/ui/label";
 import {
 	Select,
@@ -11,10 +13,124 @@ import {
 	SelectTrigger,
 	SelectValue,
 } from "@/shared/components/ui/select";
+import {
+	ToggleGroup,
+	ToggleGroupItem,
+} from "@/shared/components/ui/toggle-group";
+import {
+	formatCurrency,
+	formatDecimalForDbRequired,
+	normalizeDecimalInput,
+} from "@/shared/utils/currency";
+import { safeToNumber } from "@/shared/utils/number";
 import { cn } from "@/shared/utils/ui";
 import { PayerSelectContent } from "../../select-items";
 import type { PayerSectionProps } from "./transaction-dialog-types";
 
+type SplitInputMode = "currency" | "percentage";
+
+const SPLIT_MODE_OPTIONS = [
+	{ value: "currency", label: "R$" },
+	{ value: "percentage", label: "%" },
+] as const satisfies ReadonlyArray<{ value: SplitInputMode; label: string }>;
+
+const amountToPercent = (amount: string, total: number): string => {
+	if (total <= 0) return "";
+	const numeric = safeToNumber(normalizeDecimalInput(amount), Number.NaN);
+	if (!Number.isFinite(numeric)) return "";
+	const pct = (numeric / total) * 100;
+	return (Math.round(pct * 10) / 10).toString();
+};
+
+const percentToAmount = (percent: string, total: number): string => {
+	const pct = safeToNumber(normalizeDecimalInput(percent), Number.NaN);
+	if (!Number.isFinite(pct) || total <= 0) return "0.00";
+	const clamped = Math.min(100, Math.max(0, pct));
+	return formatDecimalForDbRequired((total * clamped) / 100);
+};
+
+function SplitModeToggle({
+	mode,
+	onModeChange,
+}: {
+	mode: SplitInputMode;
+	onModeChange: (mode: SplitInputMode) => void;
+}) {
+	return (
+		<ToggleGroup
+			type="single"
+			size="sm"
+			variant="outline"
+			value={mode}
+			onValueChange={(value) => {
+				if (value) onModeChange(value as SplitInputMode);
+			}}
+			aria-label="Modo de entrada do split"
+			className="h-7 text-xs"
+		>
+			{SPLIT_MODE_OPTIONS.map((option) => (
+				<ToggleGroupItem
+					key={option.value}
+					value={option.value}
+					className="px-2 py-0 h-7 text-xs"
+				>
+					{option.label}
+				</ToggleGroupItem>
+			))}
+		</ToggleGroup>
+	);
+}
+
+function SplitAmountField({
+	mode,
+	value,
+	totalAmount,
+	onAmountChange,
+	ariaLabel,
+}: {
+	mode: SplitInputMode;
+	value: string;
+	totalAmount: number;
+	onAmountChange: (amount: string) => void;
+	ariaLabel: string;
+}) {
+	if (mode === "currency") {
+		return (
+			<CurrencyInput
+				value={value}
+				onValueChange={onAmountChange}
+				placeholder="R$ 0,00"
+				className="h-9 w-[45%] text-sm"
+			/>
+		);
+	}
+
+	return (
+		<div className="w-[45%] space-y-1">
+			<div className="relative">
+				<Input
+					type="text"
+					inputMode="decimal"
+					value={amountToPercent(value, totalAmount)}
+					onChange={(event) => {
+						const sanitized = event.target.value.replace(/[^\d.,]/g, "");
+						onAmountChange(percentToAmount(sanitized, totalAmount));
+					}}
+					placeholder="0"
+					aria-label={ariaLabel}
+					className="h-9 w-full pr-7 text-sm"
+				/>
+				<span className="pointer-events-none absolute top-1/2 right-2 -translate-y-1/2 text-xs text-muted-foreground">
+					%
+				</span>
+			</div>
+			<p className="ml-1 text-xs text-muted-foreground">
+				{formatCurrency(safeToNumber(value))}
+			</p>
+		</div>
+	);
+}
+
 export function PayerSection({
 	formState,
 	onFieldChange,
@@ -22,17 +138,17 @@ export function PayerSection({
 	secondaryPayerOptions,
 	totalAmount,
 }: PayerSectionProps) {
+	const [splitMode, setSplitMode] = useState<SplitInputMode>("currency");
+
 	const handlePrimaryAmountChange = (value: string) => {
 		onFieldChange("primarySplitAmount", value);
-		const numericValue = Number.parseFloat(value) || 0;
-		const remaining = Math.max(0, totalAmount - numericValue);
+		const remaining = Math.max(0, totalAmount - safeToNumber(value));
 		onFieldChange("secondarySplitAmount", remaining.toFixed(2));
 	};
 
 	const handleSecondaryAmountChange = (value: string) => {
 		onFieldChange("secondarySplitAmount", value);
-		const numericValue = Number.parseFloat(value) || 0;
-		const remaining = Math.max(0, totalAmount - numericValue);
+		const remaining = Math.max(0, totalAmount - safeToNumber(value));
 		onFieldChange("primarySplitAmount", remaining.toFixed(2));
 	};
 
@@ -54,23 +170,28 @@ export function PayerSection({
 						</p>
 					</div>
 				</div>
-				<CheckboxPrimitive.Root
-					checked={formState.isSplit}
-					onCheckedChange={(checked) =>
-						onFieldChange("isSplit", Boolean(checked))
-					}
-					aria-label="Dividir lançamento"
-					className={cn(
-						"peer size-4 shrink-0 rounded-lg border shadow-xs transition-shadow outline-none focus-visible:border-ring focus-visible:ring-ring/50 focus-visible:ring-[3px]",
-						formState.isSplit
-							? "border-primary bg-primary text-primary-foreground"
-							: "border-input dark:bg-input/30",
-					)}
-				>
-					<CheckboxPrimitive.Indicator className="grid place-content-center text-current transition-none">
-						<RiSliceFill className="size-3" />
-					</CheckboxPrimitive.Indicator>
-				</CheckboxPrimitive.Root>
+				<div className="flex items-center gap-2">
+					{formState.isSplit ? (
+						<SplitModeToggle mode={splitMode} onModeChange={setSplitMode} />
+					) : null}
+					<CheckboxPrimitive.Root
+						checked={formState.isSplit}
+						onCheckedChange={(checked) =>
+							onFieldChange("isSplit", Boolean(checked))
+						}
+						aria-label="Dividir lançamento"
+						className={cn(
+							"peer size-4 shrink-0 rounded-lg border shadow-xs transition-shadow outline-none focus-visible:border-ring focus-visible:ring-ring/50 focus-visible:ring-[3px]",
+							formState.isSplit
+								? "border-primary bg-primary text-primary-foreground"
+								: "border-input dark:bg-input/30",
+						)}
+					>
+						<CheckboxPrimitive.Indicator className="grid place-content-center text-current transition-none">
+							<RiSliceFill className="size-3" />
+						</CheckboxPrimitive.Indicator>
+					</CheckboxPrimitive.Root>
+				</div>
 			</div>
 
 			<div className="flex w-full flex-col gap-2 md:flex-row">
@@ -111,14 +232,15 @@ export function PayerSection({
 								))}
 							</SelectContent>
 						</Select>
-						{formState.isSplit && (
-							<CurrencyInput
+						{formState.isSplit ? (
+							<SplitAmountField
+								mode={splitMode}
 								value={formState.primarySplitAmount}
-								onValueChange={handlePrimaryAmountChange}
-								placeholder="R$ 0,00"
-								className="h-9 w-[45%] text-sm"
+								totalAmount={totalAmount}
+								onAmountChange={handlePrimaryAmountChange}
+								ariaLabel="Porcentagem da pessoa"
 							/>
-						)}
+						) : null}
 					</div>
 				</div>
 
@@ -163,11 +285,12 @@ export function PayerSection({
 									))}
 								</SelectContent>
 							</Select>
-							<CurrencyInput
+							<SplitAmountField
+								mode={splitMode}
 								value={formState.secondarySplitAmount}
-								onValueChange={handleSecondaryAmountChange}
-								placeholder="R$ 0,00"
-								className="h-9 w-[45%] text-sm"
+								totalAmount={totalAmount}
+								onAmountChange={handleSecondaryAmountChange}
+								ariaLabel="Porcentagem do segundo pagador"
 							/>
 						</div>
 					</div>