Colony Counter — Count bacterial colonies on an agar plate from a photo
Works with JPG, PNG, WEBP · Free up to 20 MB, Premium 50 MB
Spread the colonies one layer deep on a tray or flat surface and photograph from directly above — counted detections receive dots for review. Built for microbiology labs, QC teams and research groups — review and correct each photo before adding it to a CSV or PDF tally.
- Review the photo, then count visible colonies
- Upload a photo and get an automatic count
- Review the markers to catch colonies counted twice or missed
- Free to use · No signup required · Without watermark
Upload Image
Tips for an accurate count
• Use an even, well-lit photo with the colonies fully in frame
• Keep your colonies visible and avoid overlapping items
• Dots and heatmap show retained detections — review and correct the tally
About the Bacterial Colonies Counter
The bacterial colonies counter counts visible colonies from your photo and marks detections for review. Counting starts automatically once the photo and item are ready. Visibility, overlap and similar-looking items can affect the total. Built for microbiology labs, QC teams and research groups.
How It Works
1. Photograph your colonies
2. Upload your photo to count colonies automatically
3. Review the markers and correct the tally if needed
4. Add to the tally sheet and export your count as CSV
Perfect For
• A fast draft CFU tally before the manual read is signed off
• Second-reader checks on plates near the countable range
• Keeping plate framing consistent across a study
• Teaching labs where every student counts the same plate
Colony counter app for a draft CFU tally from a plate photo
Microbiology labs, QC teams and teaching labs use this colony counter as a draft read of an agar plate: a fast tally before the manual count is signed off, a second reader on plates where the count is borderline, and a way to keep plate photos framed the same way across a study. It counts the colonies visible in the photo and marks each one; the number is yours to review, and it is not a validated instrument or a regulatory method.
Photograph the plate from directly above on a dark, non-reflective surface, with soft light from the side or a light box underneath. Condensation on the lid forms droplets that look a lot like small colonies, so take the lid off or shoot through the base with the plate inverted. The plate rim reflects light as a bright ring; crop to the agar with the image cropper before counting. Writing on the base shows through pale agar, so label the plate edge instead. In Similar items, mark two or three clear, well-separated colonies as examples, choosing different sizes if the plate mixes them.
Touching colonies are often read as one, so check every marker where growth meets and adjust the tally row by hand. Record each plate as a row labelled with sample and dilution; turning the count into CFU is your own calculation. For microscope fields rather than plates, the cell counter is the matching page.
Plate photo checks
- Lid off, or plate inverted, so condensation does not show
- Dark matte background and soft, even light
- Photo cropped to the agar so rim glare is out of frame
- Two or three clear colonies marked as examples
Frequently asked questions
- Do the items need to be separated before counting?
- Slight touching can work, but full overlaps hide items and make the result less reliable. Spread them one layer deep under even light, mark a clear example, and review every result marker.
- Can it separate colonies that have grown into each other?
- Merged growth is the hardest case and a confluent patch is often marked as one. Mark two or three clear, well-separated colonies as your examples, then review the markers and split or add any the counter merged. Plates read while the colonies are still discrete give the most reliable draft.
- What if the photo has more than just colonies in it?
- The counter automatically looks for colonies in your photo. Similar-looking distractors can still affect the result, so review every marker before using the total.
- Can I count several photos into one total?
- Yes — count each photo and add every reviewed result to the tally sheet as a labelled row. Export the tally as CSV or a PDF report, or save it to your account.
- Is it free and private?
- Yes. You can count, review and download a free result without an account. Downloads are free without a watermark. No signup required. Server-processed photos are encrypted in transit and removed under our Security policy.
What you can do with Object Counter
Review the main capabilities before you begin.
- Count objects in a photo instead of tallying by hand
- Tally coins, pills, cells, parts and beads
- Optionally mark an example to target a specific item
- Review counted detections with overlay markers
- Run a bulk audit across many photos
- Fine-tune sensitivity to ignore tiny specks
Settings reference
15 settings
Available controls for Object Counter.
Upload
- Single photo / Bulk auditPresets
- Choose a single-photo count or a Premium bulk audit. Review every result.Options: Single photoBulk audit
Count
- Included markersSliderRange: 0–1 · Default: 0.21
- Starts at 21%; slide toward Show more to include weaker markers or Only strongest to hide them.
- Overlay stylePresets
- Choose dots, a heatmap, both or a clean preview.Options: BothDotsHeatNone
- What to countText input
- Enter the item to count, then press Enter or leave the field to start automatically. Review every result marker.
Advanced
- Result overlayDropdown
- Choose how count markers appear in the on-screen preview; the download keeps its own markers.Options: Dots + heatmapDots onlyHeatmap only
Tally
- Add to tallyOne-click
- Add this count to the tally sheet under the name of the object that was counted. Signed-in accounts add finished counts automatically unless that is turned off under Account settings; in bulk mode every photo also has its own Add to tally button.
- LabelText input
- Rename a tally row. Edits and removals wait until you choose Save changes, so you can fix several rows at once.
- CountNumber input
- Correct a row's count; totals, the chart and exports follow once the change is saved.
- Save changesOne-click
- Apply every edited or removed tally row in one step, or choose Discard changes to leave the sheet as it was.
Chart
- By objectPresets
- The chart is the same in every counting tool and covers the tallies of all of them. By object draws a separate line chart for each tally name, such as pipes and people. By tool draws a chart for each counting tool.Options: By objectBy tool
- PeriodPresets
- Choose how far back the chart looks. Days without a count appear as zero.Options: 7 days30 days90 days12 months
History
- Counting setupGallery
- Keep comparable counts together. A first setup is created for you, so the first count can be saved straight away.
- Observed atText input
- The date and time of the count, shown as a date and a time field.
- NotesText input
- Starts with every detected object and its count, one per line, such as Pipes - 11. Edit it before saving.
- Save countOne-click
- Save the count to your account history. Open a saved count later to correct it or download its source photo.
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Shareable Stock-Take Reports for Teams
Save a completed stock-take to your account, generate a branded PDF report, and share a read-only link so managers or teammates can review the count without re-uploading anything.
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Watch each transformation land
Every photo crosses the slash untouched and comes out the other side finished.
