Measure Radius & Diameter
Measure radius and diameter of circles in images with precision. Click the center point, then click a point on the edge of the circle. Perfect for design, engineering, and analysis work.
or drop image here or paste
Measure radius and diameter of circles in images with precision. Click the center point, then click a point on the edge of the circle. Perfect for design, engineering, and analysis work.
or drop image here or paste
Click the center point, then click a point on the edge of the circle. Drag points to adjust.
No measurements yet. Click on the image to start.
Measure Radius is a free online tool for measuring circular dimensions including radius and diameter in photographs and images. Click to place a center point and edge point to instantly calculate radius, diameter, and circumference measurements in pixels. Perfect for measuring circular objects in product photos, hole sizes in engineering drawings, circular features in architectural plans, or round structures in scientific images. The circle measurement tool displays precise measurements with visual circle overlays you can download.
Upload your image containing the circular feature you want to measure. Click once to place the center point of the circle at the exact middle of your circular object. Click a second time on the edge or perimeter of the circle to define the radius - the tool instantly calculates and displays radius, diameter, and circumference values. A complete circle overlay appears showing the measured circular dimensions visually. Drag either the center or edge point to adjust your measurement for precise positioning. Add multiple circle measurements to analyze different circular features in the same image. Download your annotated image as PNG, JPG, or WebP with all circle measurements, overlays, and dimension labels permanently visible.
Measure hole diameters, bolt circle patterns, and circular component dimensions in engineering CAD drawings and technical specifications. Calculate pipe diameters, circular duct sizes, and round feature dimensions from plumbing plans and HVAC layouts. Verify circular part dimensions, ring sizes, gasket diameters, and bearing measurements from product design images and manufacturing blueprints. The radius measurement tool works on scanned technical drawings, digital design files, smartphone photos of physical parts, or catalog product images. Measure multiple concentric circles or bolt patterns within the same component by adding separate circle measurements for comprehensive dimensional analysis.
Use the circle measurer for construction projects when verifying column diameters, circular window sizes, or round feature dimensions from architectural plans and blueprints. Machinists and fabricators measure hole diameters, shaft sizes, and circular bore dimensions from workshop drawings and part specifications. Scientists measure cell diameters in microscopy images, circular colony sizes in petri dish photos, or circular feature dimensions in research imagery. Woodworkers calculate circle radii for curved cuts, round table dimensions, or circular inlay sizes from project plans. Landscape designers measure circular patio diameters, round planter sizes, or circular fountain dimensions from site plans and garden layouts.
Export measured images at full original resolution with circle overlays and dimension labels automatically scaled for clarity on any image size from small part photos to large architectural plans. PNG format preserves measurement accuracy with crisp circle outlines and clear radius/diameter labels perfect for professional engineering documentation, manufacturing work orders, and quality control reports. WebP format reduces file size by 30-50% while maintaining sharp circle overlays and readable dimension text - ideal for uploading annotated technical images to collaboration platforms or sharing measurement specifications via email. All downloads include complete radius, diameter, and circumference values permanently embedded for accurate record keeping, dimensional verification, and manufacturing reference documentation.