Is my image uploaded?

No. Lane detection, band integration and the chart are computed in your browser; the image never leaves your device.

Which background method should I use?

The default lane baseline draws a straight line between the band's top and bottom edges and integrates only the area above it — robust to vertical smears and gradients, as in ImageJ Gel Analyzer. Border median works for very flat backgrounds.

Why divide by a loading control?

Lanes never receive exactly the same amount of protein. Dividing the target band by the same lane's β-actin or GAPDH band corrects loading differences before expressing results as fold change vs control.

What do the stars on the bar chart mean?

Each group is compared with the control by Welch's t-test with Holm correction. Groups need at least two lanes to be tested; whether lanes are technical or biological replicates depends on your design.

Research workbench

Western Blot Densitometry

Free online Western blot densitometry. Frame lanes once, drag once to mark every band, get background-corrected band volumes, loading-control normalisation and an automatic bar chart. Runs in your browser.

Upload a Western blot image

PNGJPG

PNG/JPEG, drag & drop or click. Images are processed in your browser and never uploaded.

Western blot quantification in three steps

Frame the lanes. Drag one box over all lanes. The tool estimates the lane count, splits at the faintest columns between lanes and centres each lane on its signal. Lane count and width stay adjustable.

Mark bands in one drag. Drag a horizontal strip along one molecular weight and every lane's band is marked. A second strip becomes the loading control. “Snap bands” nudges each lane's box to its strongest signal, correcting smiling gels.

Group and chart. Use Quick groups to enter group names and replicates, pick the control, and the bar chart (mean ± SD or SEM, individual points, significance vs control) builds itself, ready to export as PNG/SVG and CSV.

Limits of densitometry

Band volumes are only meaningful in the linear range. Bands with saturated pixels (⚠ in the table) are underestimated — use a shorter exposure. JPEG compression and auto-contrast also change gray values; export lossless PNG from the original TIFF when possible.