diff --git a/apps/web/src/app/core/format.spec.ts b/apps/web/src/app/core/format.spec.ts
index ee52c53..29673a7 100644
--- a/apps/web/src/app/core/format.spec.ts
+++ b/apps/web/src/app/core/format.spec.ts
@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { formatDate, formatNumber, parseDecimal } from './format';
+import { formatDate, formatNumber, parseDecimal, todayIso } from './format';
 
 describe('formatNumber', () => {
   it('importes con decimales fijos y miles', () => {
@@ -38,3 +38,10 @@ describe('parseDecimal', () => {
     for (const v of ['', '  ', 'abc', '1.2.3', '--']) expect(parseDecimal(v), v).toBeNull();
   });
 });
+
+describe('todayIso', () => {
+  it('da la fecha local, no la del día UTC', () => {
+    expect(todayIso(new Date(2026, 9, 19, 23, 30))).toBe('2026-10-19');
+    expect(todayIso(new Date(2026, 0, 5, 0, 10))).toBe('2026-01-05');
+  });
+});
diff --git a/apps/web/src/app/core/format.ts b/apps/web/src/app/core/format.ts
index c471ee1..6f02d53 100644
--- a/apps/web/src/app/core/format.ts
+++ b/apps/web/src/app/core/format.ts
@@ -36,3 +36,9 @@ export function parseDecimal(text: string): number | null {
   const n = Number.parseFloat(cleaned);
   return Number.isFinite(n) ? n : null;
 }
+
+/** La fecha de hoy en la zona horaria del usuario, como `yyyy-MM-dd` (`toISOString` daría la del día UTC, que de noche es otra). */
+export function todayIso(now = new Date()): string {
+  const p = (n: number): string => String(n).padStart(2, '0');
+  return `${now.getFullYear()}-${p(now.getMonth() + 1)}-${p(now.getDate())}`;
+}
diff --git a/apps/web/src/app/features/banking/payment-form.page.ts b/apps/web/src/app/features/banking/payment-form.page.ts
index 5e32948..10c73db 100644
--- a/apps/web/src/app/features/banking/payment-form.page.ts
+++ b/apps/web/src/app/features/banking/payment-form.page.ts
@@ -5,7 +5,7 @@ import { ActivatedRoute, Router, RouterLink } from '@angular/router';
 import type { SlListResponse } from '@basic-erp/sap-types';
 import { map } from 'rxjs';
 import { API_URL, apiErrorMessage } from '../../core/api';
-import { formatNumber } from '../../core/format';
+import { formatNumber, todayIso } from '../../core/format';
 import { SlDocumentApi } from '../../core/sl/sl-document';
 import { DateField, LookupField, NumberField, SelectField, TextField, TextareaField } from '../../shared/form';
 import type { DetailColumn } from '../../shared/grid/grid.types';
@@ -21,7 +21,7 @@ import type { PaymentDocType, PaymentScreen } from './payment-types';
 type Row = Record<string, unknown>;
 
 const text = (v: unknown): string => (v === null || v === undefined ? '' : String(v));
-const today = (): string => new Date().toISOString().slice(0, 10);
+const today = (): string => todayIso();
 const dateOnly = (v: unknown): string => (typeof v === 'string' ? v.slice(0, 10) : '');
 const money = (n: number): string => formatNumber(n, 2);
 
diff --git a/apps/web/src/app/features/finance/journal-form.page.css b/apps/web/src/app/features/finance/journal-form.page.css
index 22a76bc..3eca167 100644
--- a/apps/web/src/app/features/finance/journal-form.page.css
+++ b/apps/web/src/app/features/finance/journal-form.page.css
@@ -6,3 +6,4 @@ h3 { margin: 14px 0 4px; font-size: 13px; font-weight: 600; }
 .totals td:last-child { text-align: right; font-variant-numeric: tabular-nums; }
 .totals tr.strong td { font-weight: 600; border-top: 1px solid var(--field-b); }
 .confirm { color: var(--danger, #b00020); margin-right: 8px; }
+.ask { display: flex; align-items: center; gap: 8px; margin: 4px 0 6px; padding: 4px 8px; background: var(--warn-bg); border: 1px solid var(--line); border-radius: var(--radius); }
diff --git a/apps/web/src/app/features/finance/journal-form.page.html b/apps/web/src/app/features/finance/journal-form.page.html
index 0afb7e8..24546ea 100644
--- a/apps/web/src/app/features/finance/journal-form.page.html
+++ b/apps/web/src/app/features/finance/journal-form.page.html
@@ -20,7 +20,7 @@
     </div>
     <div class="sbo-col">
       <sbo-date-field label="Fecha de contabilización" [(value)]="referenceDate" [readonly]="saved()" required />
-      <sbo-date-field label="Fecha de vencimiento" [(value)]="dueDate" [readonly]="saved()" />
+      <sbo-date-field label="Fecha de vencimiento" [value]="dueDate()" (valueChange)="onDueDate($event)" [readonly]="saved()" />
       <sbo-date-field label="Fecha del documento" [(value)]="taxDate" [readonly]="saved()" />
     </div>
   </div>
@@ -40,6 +40,13 @@
   </div>
 
   <h3>Líneas</h3>
+  @if (pendingDue(); as due) {
+    <p class="ask" role="alert">
+      ¿Poner también el vencimiento {{ formatDate(due) }} en las líneas?
+      <button type="button" class="btn main" (click)="applyDue(true)">Sí, actualizar</button>
+      <button type="button" class="btn" (click)="applyDue(false)">No, dejarlas</button>
+    </p>
+  }
   <sbo-rows-table [columns]="columns" [rows]="lines()" (rowsChange)="setLines($event)" [readonly]="saved()" [removable]="!saved()" emptyText="Sin líneas." />
   @if (!saved()) {
     <p class="row">
diff --git a/apps/web/src/app/features/finance/journal-form.page.ts b/apps/web/src/app/features/finance/journal-form.page.ts
index bf27a9c..bad11ab 100644
--- a/apps/web/src/app/features/finance/journal-form.page.ts
+++ b/apps/web/src/app/features/finance/journal-form.page.ts
@@ -5,7 +5,7 @@ import { ActivatedRoute, Router, RouterLink } from '@angular/router';
 import type { SlListResponse } from '@basic-erp/sap-types';
 import { firstValueFrom, map } from 'rxjs';
 import { API_URL, apiErrorMessage } from '../../core/api';
-import { formatNumber } from '../../core/format';
+import { formatDate, formatNumber, todayIso } from '../../core/format';
 import { SlDocumentApi } from '../../core/sl/sl-document';
 import { DateField, LookupField, SboField, SelectField, TextField, TextInput } from '../../shared/form';
 import type { DetailColumn } from '../../shared/grid/grid.types';
@@ -46,7 +46,7 @@ const ASSOCIATED_ACCOUNT_LOOKUP: VhLookup = {
 const OBJECT_TYPE = 30;
 
 const text = (v: unknown): string => (v === null || v === undefined ? '' : String(v));
-const today = (): string => new Date().toISOString().slice(0, 10);
+const today = (): string => todayIso();
 const dateOnly = (v: unknown): string => (typeof v === 'string' ? v.slice(0, 10) : '');
 
 /**
@@ -91,8 +91,9 @@ export class JournalFormPage {
   // --- el borrador (o el asiento guardado, mostrado) -----------------------------------------
 
   protected readonly referenceDate = linkedSignal(() => (this.doc() ? dateOnly(this.doc()!['ReferenceDate']) : today()));
-  protected readonly dueDate = linkedSignal(() => dateOnly(this.doc()?.['DueDate']));
-  protected readonly taxDate = linkedSignal(() => dateOnly(this.doc()?.['TaxDate']));
+  // un asiento nuevo arranca con todas las fechas de hoy (cabecera y líneas)
+  protected readonly dueDate = linkedSignal(() => (this.doc() ? dateOnly(this.doc()!['DueDate']) : today()));
+  protected readonly taxDate = linkedSignal(() => (this.doc() ? dateOnly(this.doc()!['TaxDate']) : today()));
   protected readonly series = linkedSignal<number | null>(() => (this.doc() ? Number(this.doc()!['Series']) || null : null));
   protected readonly memo = linkedSignal(() => text(this.doc()?.['Memo']));
   protected readonly reference = linkedSignal(() => text(this.doc()?.['Reference']));
@@ -104,7 +105,7 @@ export class JournalFormPage {
   protected readonly indicatorLookup = INDICATOR_LOOKUP;
   protected readonly lines = linkedSignal<Row[]>(() => {
     const rows = ((this.doc()?.['JournalEntryLines'] as Row[] | undefined) ?? []).map((l) => ({ ...l }));
-    return this.doc() ? rows : [{}, {}];
+    return this.doc() ? rows : [{ DueDate: today() }, { DueDate: today() }];
   });
 
   protected readonly saving = signal(false);
@@ -227,8 +228,26 @@ export class JournalFormPage {
     this.message.set(null);
   }
 
+  /** Vencimiento nuevo de la cabecera que espera la respuesta del usuario para pasarlo a las líneas. */
+  protected readonly pendingDue = signal<string | null>(null);
+
+  protected formatDate = formatDate;
+
+  /** Al cambiar el vencimiento de la cabecera se pregunta si las líneas con otro vencimiento lo toman también. */
+  protected onDueDate(value: string): void {
+    this.dueDate.set(value);
+    const differ = this.lines().some((l) => (l['DueDate'] ?? '') !== value);
+    this.pendingDue.set(value && differ ? value : null);
+  }
+
+  protected applyDue(yes: boolean): void {
+    const value = this.pendingDue();
+    this.pendingDue.set(null);
+    if (yes && value) this.setLines(this.lines().map((l) => ({ ...l, DueDate: value })));
+  }
+
   protected addLine(): void {
-    this.setLines([...this.lines(), {}]);
+    this.setLines([...this.lines(), { DueDate: this.dueDate() }]);
   }
 
   /** Lleva a la última línea lo que falta para cuadrar: el debe o el haber, según el lado que sobra. */