Medición de Pantalla de Precisión, Creada para Todos.

Nuestra Misión

Regla Online Precisa se fundó en una observación simple: cuando necesitas medir algo físico y no tienes una regla cerca, tu smartphone o portátil debería ser la mejor alternativa. Yet most browser-based measurement tools rely on rough estimates, fixed assumptions about screen size, or camera-based approaches that introduce lens distortion and perspective errors.

Nos propusimos construir la regla online más precisa posible — una que use la cuadrícula de píxeles físicos reales de tu pantalla. The result is a free tool that works on any device, in any browser, without plugins or installations.

Ingeniería de Precisión

En el corazón de nuestra regla online hay un motor de renderizado basado en canvas que dibuja cada marca, etiqueta y subdivisión directamente en un lienzo HTML5. — no CSS rounding errors, no sub-pixel blurring, and consistent results across operating systems and browser engines.

Our accurate online ruler supports three independent calibration methods:

• Auto-Detect Device — matches your screen from 130+ known device profiles (iPhone, Samsung Galaxy, Google Pixel, MacBook, Surface, and more) for instant, factory-precise calibration.
• Screen Diagonal — enter your display's diagonal size for a custom PPI calculation based on your screen's native resolution.
• Credit Card Calibration — place any ISO/IEC 7810 ID-1 card on the on-screen guide and adjust until it matches, achieving ±0.5% accuracy.

Once calibrated, the ruler displays at actual scale — a 10 cm line on screen equals exactly 10 cm in the real world. All unit modes maintain this precision, instantly switching without losing calibration.

Why Screen-Based Measurement?

Tools that rely on camera input face fundamental challenges: lens distortion, variable focal length, inconsistent lighting, and parallax error all degrade accuracy. A screen-based approach avoids these problems entirely because your display has fixed physical dimensions and a known pixel grid. By accurately measuring PPI (pixels per inch), the tool renders marks that correspond directly to real-world lengths.

This makes screen-based rulers inherently more reliable than camera-based alternatives. No permission prompts, no camera initialization, no calibration patterns to print — just open the page and start measuring in seconds.

Diseño Centrado en el Usuario

Cada característica de esta regla online fue diseñada pensando en patrones de uso reales: guías de medición arrastrables, bloqueo, modo oscuro, pantalla completa y configuración persistente.

• Dark Mode — comfortable viewing in low-light environments with a full dark theme applied to rulers and controls.
• Fullscreen Mode — distraction-free measuring across your entire display.
• Edge Rulers — rulers positioned precisely at screen edges for maximum workspace.
• Persistent Settings — your PPI, unit preference, and dark mode are saved locally so you never need to recalibrate on the same device.

We also designed for mobile — at 768px and below, the interface adapts with sticky rulers, a compact navigation dropdown, larger touch targets, and optimised layout that preserves full functionality on phones.

Nuestro Compromiso

Regla Online Precisa es y será siempre gratuita. Sin cuenta requerida, sin datos recopilados, sin anuncios que interfieran con la medición.

We actively maintain and improve the tool based on user feedback. If your device isn't recognised, a measurement seems off, or you have a suggestion, contact us and we will address it promptly.

Device database last verified: July 2026. Calibration methodology reviewed and consistent with ISO/IEC 7810 payment card standards.