Protractor Master: Angle App

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About this app

【Turn Your Phone into a Protractor Anytime, Anywhere】
Protractor Master is a simple yet powerful angle measurement tool that transforms your smartphone into a precise ruler. No need to carry a physical protractor anymore. Whether directly on your screen or over a photo you have taken, simply drag with your fingers to measure angles quickly and accurately.

【Two Powerful Measurement Modes】
■ Screen Measure (Protractor Mode)
Two measurement lines (green and blue) appear centered at the edge of your screen. Simply drag the lines to match the angle you want to measure, and the real-time angle between them is displayed in 0.1° increments. Perfect for checking the angles of everyday objects on the spot.

■ Photo Measure (Photo Mode)
Snap a picture with your camera or import an image from your photo library to measure angles directly on the photo.
1. Align the center point with the vertex of the angle.
2. Adjust the two lines along the sides of the angle.
That’s it! It is ideal for things you want to measure carefully later, such as furniture, buildings, blueprints, or slopes. Photo Mode supports a full 0-360° range.

【Must-Have Features for High Precision】
● 0.1° Fine-Tuning: Use the "+1°/−1°" and "+0.1°/−0.1°" buttons for delicate adjustments that are hard to achieve with finger dragging alone.
● Lock Feature: Lock the screen after measuring to prevent the angle from shifting. Perfect for showing values to others while working.
● Full-Screen Extension Mode: Extend the measurement lines to the edges of the screen, making it easier to align with long edges.
● Left/Right Layout: Position the center of the protractor on either the left or right edge for natural operation, whether you are right-handed or left-handed.
● One-Tap Reset: Return to the initial state instantly at any time.
● Dark Mode Support: Switch between Light, Dark, or System settings. Easy on the eyes and highly visible in dark environments.
● Collapsible Panel: Minimize the angle display panel to maximize your screen workspace during measurements.

【Perfect for Various Scenes】
・DIY & Woodworking: Checking angles for timber, shelves, and home improvement.
・Crafts & Sewing: Creating patterns for handmade projects and textiles.
・Home Decor: Checking furniture placement and interior layouts.
・Education & Study: Helping students grasp angle concepts in math and geometry.
・Design & Art: Confirming angles in blueprints, illustrations, and digital art.
・Outdoor & Surveying: Measuring the slope of roofs, hills, or inclines from photos.

【Simple & Ready to Use】
No complicated setup required. Start measuring the moment you open the app. A quick user guide is available for beginners, and a built-in FAQ in the settings will help resolve any questions. The intuitive design ensures a seamless experience for everyone, from beginners to professionals.

【Multi-Language Support】
This app supports many languages, including English, as well as Spanish, French, and German.

【Works Fully Offline】
All calculations are processed entirely on your device. It works perfectly without an internet connection, allowing you to use it with confidence on jobsites, outdoors, or on the go.

Make angle measurement effortless.
Updated on
May 29, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
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No data collected
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