Free ABCDE questions
ABCDE mole checker
Answer 5 free questions about your mole, based on the ABCDE criteria dermatologists use — or scan a photo of it with AI. Either way you get a suggested next step, not a diagnosis.
AI ABCDE photo scan
Checks the shape, border and colour of your spot — the A, B and C of ABCDE — in about a minute.
AI checks A, B and C
Your result + next step
$4.99 per check. CheckMole doesn't diagnose.
A
Asymmetry
Is your mole symmetrical?
B
Border
How do the edges look?
C
Color
How many colors do you see?
D
Diameter
How large is it?
E
Evolution
Has it changed recently?
The ABCDE Rule — Visual Guide
The screening method dermatologists recommend for self-examination.
A
Asymmetry
One half does not match the other half
Normal
Both halves match
Warning
Halves don't match
B
Border
Edges are irregular, ragged, or blurred
Normal
Smooth, well-defined edge
Warning
Ragged, blurred edges
C
Color
Multiple colors or uneven color distribution
Normal
One uniform color
Warning
5+ colors mixed
D
Diameter
Larger than 6mm — about the size of a pencil eraser
Normal
Under 6mm
Warning
Over 6mm (pencil eraser)
E
Evolution
Any change in size, shape, color, or symptoms over time
Normal
No change over 12 months
Warning
Grew, darkened, irregular
Most important: Evolution (E) is considered the single most critical criterion. Any mole that is changing — in size, shape, color, or producing new symptoms like itching or bleeding — should be evaluated by a dermatologist regardless of other features. This guide is for screening only.
Watch the 5 signs
What is the ABCDE rule?
The ABCDE rule is a simple memory aid, used by health bodies such as the American Academy of Dermatology (AAD) and the NHS, to describe changes in a mole or spot that should be checked by a doctor. It stands for Asymmetry, Border, Color, Diameter and Evolving. It helps you notice warning signs on your skin, but it is not a diagnosis.
Use it during regular self-checks: look over your skin in good light, including your back, scalp, soles and nails. Compare both sides of your body and note any spot that stands out or changes. Clear, dated photos make it easier to track a spot over time and to show a clinician what you have seen.
A — Asymmetry
One half of the spot is unlike the other half. If you imagine a line through the middle, the two sides do not match.
B — Border
The outline is irregular, scalloped or poorly defined. Edges may look blurred, notched or as if they are spreading into the surrounding skin.
C — Color
The color varies from one area to the next: shades of tan, brown or black, or patches of white, red or blue. New colors appearing in an existing mole also count.
D — Diameter
Melanomas are usually greater than 6 mm (about the size of a pencil eraser) when diagnosed, but they can be smaller. Growth over time matters more than any single measurement.
E — Evolving
The spot looks different from the rest or is changing in size, shape or color. The NHS also lists a mole that bleeds, itches, or becomes swollen, sore or crusty.
What this self-check can and can't tell you
This free quiz is an educational prompt, not a medical assessment. Melanomas can be smaller than 6 mm. Some have little or no pigment (amelanotic) and may appear pink or skin-colored. Nodular melanomas can be raised, firm and growing (the EFG prompt: Elevated, Firm, Growing) and may not fit the ABCDE pattern at all. A “normal” ABCDE result does not rule out skin cancer, and only a biopsy examined by a pathologist can diagnose melanoma. Use your result to help decide whether to book an appointment; it does not replace a professional skin examination. A reassuring result should never delay an appointment if something worries you.
When to see a doctor
See a GP or dermatologist promptly if a mole or spot is new, changing in size, shape or color, bleeding, itchy, painful, crusty or inflamed, or if you have a sore that does not heal. Also seek advice if one spot looks different from all your others (the “ugly duckling” sign). The NHS notes that a GP may make an urgent referral to a specialist if symptoms could be cancer. If in doubt, get it looked at.
Sources
Printable one-page version for clinics, schools and community groups.
About this tool
The ABCDE rule (Asymmetry, Border, Color, Diameter, Evolution) is the standard self-screening method recommended by the American Academy of Dermatology. This tool guides you through each criterion. It is not a medical diagnosis — learn more about melanoma detection.