Coffee grind size analyzer
Estimate coffee particle sizes from a photo with a ruler or known-size reference.
Upload a photo
Spread the grounds on plain white paper and place a ruler beside them. Photograph from directly above, with the grounds separated and in focus.
JPG, PNG or WebP · Up to 25 MB
Photo preparation and measurement guide
Prepare a useful photo
Place a small amount of grounds in a single layer on plain white paper. Separate the particles so their edges do not touch. Put a ruler beside the sample, use bright even light, focus on the grounds, and point the camera straight down, perpendicular to the surface.
- Choose a JPG, PNG or WebP image up to 25 MB.
- Mark both ends of a visible reference length and enter its real length in millimeters.
- Draw a rectangle around the grounds, leaving the ruler and photo edges outside.
- Run the analysis and check that the detected marks follow individual particles.
How to read the estimate
How to read the estimate
The analyzer reports the equivalent-circle diameter from each detected particle’s two-dimensional image area. D10, D50 and D90 are number-based percentiles of detected particles, and the histogram groups those detections by diameter. For method-based starting points, see the coffee grind size chart.
Photo grind analyzer questions
Photo grind analyzer questions
How does the photo analyzer estimate particle size?
You mark two points on a reference of known length, then select a rectangular sample area. The browser measures detected particle areas and reports the diameter of a circle with the same area.
What can I use as a size reference?
Use a ruler or another flat object with a known, visible distance. Enter that distance in millimeters and mark its endpoints in the photo. Point the camera straight down, perpendicular to the surface.
Why must the grounds be separated?
Touching or overlapping grounds can be detected as one shape. Spread a small sample in a single layer on a plain, contrasting surface and keep the reference outside the sample rectangle.
What do D10, D50 and D90 mean here?
They are number-based percentiles: the reported diameter is at or below the size containing 10%, 50% or 90% of detected particles. Each detected particle has equal weight, regardless of its area.
Can the analyzer measure coffee fines?
Only when a particle is large enough to be resolved in the source image. The page reports an approximate resolution floor; smaller fines cannot be counted reliably and are not represented as measured particles.
Are the measurements laboratory accurate?
No. Lighting, focus, shadows, perspective, surface contrast and the detector affect the estimate. Treat the overlay and values as a visual comparison aid, not a laboratory measurement or validated physical instrument.
Can it tell me the best grind or convert grinder clicks?
No. Particle size alone cannot determine the best extraction setting, and grinders differ in burr geometry and calibration. The tool does not recommend a brew setting or convert clicks.
Is my photo uploaded?
No. The selected image is decoded and analyzed in your browser. The analyzer does not send the photo to Beanloom or store it.