You cannot tell for certain whether a mole is skin cancer from a photograph or online checklist. The useful question is whether it has warning signs that mean it should be assessed in person, and whether you have a clear record of change.
The ABCDE warning signs
- A — Asymmetry: one half does not match the other.
- B — Border: irregular, ragged, notched or blurred edges.
- C — Colour: uneven colour or several colours in one spot.
- D — Diameter: larger size can matter, although melanomas can be smaller than 6 mm.
- E — Evolving: change in size, shape, colour, surface or symptoms.
The “ugly duckling”—a spot that looks different from the rest—also deserves attention. Not every skin cancer follows ABCDE, so do not use the checklist as an all-clear.
What should I do next?
If a mole is new, changing, bleeding, painful, growing, not healing or worries you, arrange an in-person assessment with your GP or a skin-cancer clinic. A clinician may use dermoscopy and, where required, biopsy to make a diagnosis.
Document the same spot over time
While photographs do not diagnose a mole, a structured photo record can preserve what was seen and when. Free AI skin check, then choose monthly reminders, three-monthly reminders or no reminders. Follow-up photographs stay connected to the right spot.
If comparison supports a change, Skin360AI provides a free connected summary you can take to a clinician. It does not make referral, biopsy or treatment decisions. Read how Skin360AI monitoring works or see the separate online doctor-review option.
This information is general and is not a diagnosis. It cannot rule skin cancer in or out.
Worried about a mole, mark or changing skin area?
Most skin-cancer advice tells you to watch for change. Skin360AI helps you keep photos of one or more spots connected over time. A spot can be a mole, freckle, mark, lump, sore, patch or any skin area you want to watch. It is not a diagnosis and cannot rule skin cancer in or out.
If a lesion is new, changing, bleeding, non-healing or worrying you, arrange an in-person GP or skin-cancer clinic assessment.
Frequently asked questions
Is my mole cancerous?
Most moles are not. A mole is more likely to need checking if it is changing (in size, shape or colour), has an irregular border or more than one colour, is larger than about 6 mm, or looks different from your other moles. A mole that has looked the same for years is far less concerning than one changing now. If you are unsure, have it reviewed.
Can a normal mole turn into skin cancer?
Most melanomas actually arise on clear skin, but some do start in an existing mole. That is why a mole that is changing is worth checking, even if it was previously normal.
Should I worry about a new mole as an adult?
New moles are common up to about age 40. A genuinely new or changing mole in an adult is worth having reviewed, particularly if it looks different from your others.
How quickly should I get a changing mole checked?
Soon. Most melanomas are very treatable when caught early, so it is better to check a changing or unusual mole promptly than to wait and watch for months.
What is the ugly duckling sign?
It is the mole that looks different from all your others — different colour, shape or size. That standout spot, or any mole that changes, deserves a check; and remember not every melanoma is dark, so watch for pink or firm growing lumps too.
Check and watch the spots you care about over time
Use the free AI-assisted skin check to save photos of moles, marks, lumps, sores, patches or other skin areas you want to watch. A photo record is not a diagnosis or a cancer all-clear.
Free AI skin check →See how skin monitoring works →
A structured photo record is not a diagnosis, cannot exclude skin cancer and does not replace an in-person examination.