Is this skin cancer? What a photo can and can't tell you
No photo, app or AI can tell you for certain whether a spot is skin cancer. That takes a doctor, usually with a dermatoscope and sometimes a biopsy. What a photo can do is show whether a spot has the visible features doctors treat as warning signs, so you can decide how soon to get it looked at.
Most spots people worry about turn out to be harmless. The ones that aren't are far easier to treat when they are found early, which is why a spot that is new, changing or not healing deserves a proper look rather than more searching.
How the photo check works
1.
Take a close, sharp photo
In daylight, about 5–10 cm (2–4 in) from the skin, with the spot in the middle and in focus. Tick the consent box first: your photo goes to our AI provider only after you agree.
2.
The AI looks at what the photo shows
It describes the shape (asymmetry), the border and the colours of the spot. If the photo is too blurry, too dark or doesn't show skin clearly, it tells you, so you can retake it.
3.
You get a result and a next step
After you unlock it, a few quick questions (has it changed, how big is it, does it bleed, itch or not heal) are combined with the photo by fixed safety rules: keep watching and check again in a month, show it to a dermatologist in the next few weeks, or book a visit soon.
For a photo the check can use
- Daylight from a window, no flash
- 5–10 cm (2–4 in) away, phone held still
- Tap the spot on screen so it is sharp
- Move hair, jewellery and clothing out of the way
What it looks at: the ABCDE signs and the ugly duckling
Dermatologists teach the ABCDE checklist for spotting possible melanoma. A photo can show the first three; the last two need your answers, and later photos of the same spot.
- AFrom the photo
Asymmetry
One half of the spot doesn't match the other.
- BFrom the photo
Border
The edge is ragged, notched or blurred into the skin around it.
- CFrom the photo
Colour
Several shades of brown or black, or patches of red, white or blue.
- DFrom your answer
Diameter
Larger than about 6 mm, the size of a pencil eraser. Melanomas can be smaller.
- EFrom your answers and later photos
Evolving
Any change in size, shape or colour, or new bleeding, itching or crusting.
The ABCDE Rule — Visual Guide
The screening method dermatologists recommend for self-examination.
Asymmetry
One half does not match the other half
Normal
Both halves match
Warning
Halves don't match
Border
Edges are irregular, ragged, or blurred
Normal
Smooth, well-defined edge
Warning
Ragged, blurred edges
Color
Multiple colors or uneven color distribution
Normal
One uniform color
Warning
5+ colors mixed
Diameter
Larger than 6mm — about the size of a pencil eraser
Normal
Under 6mm
Warning
Over 6mm (pencil eraser)
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.
Drawn illustrations, not photos of real skin.
The ugly duckling sign
Most people's moles look alike. A spot that looks different from all your others deserves a doctor's look even if it passes ABCDE. One photo can't compare it with the rest of your skin, so the check asks you.
Skin cancers that don't look like moles
Basal cell and squamous cell carcinoma, the most common skin cancers, often look nothing like a mole: a shiny pink or pearly bump, a rough or crusted patch, or a sore that bleeds, scabs and never quite heals. For raised spots doctors also use EFG: elevated, firm and growing for more than a month. These are judged mostly by how the spot behaves over time, which is why the check asks whether it bleeds, crusts or does not heal.
What it cannot do
- It cannot diagnose skin cancer, and it cannot tell you a spot is safe. Only a doctor can, often with a biopsy.
- It cannot measure size or see change from a single photo. That is why it asks you, and why a second photo weeks later matters.
- It cannot see beneath the surface the way a dermatoscope does, or feel whether a bump is firm.
- It is built for one spot at a time, not for rashes or large areas of skin. Spots on the scalp, under a nail, on the genitals or inside the mouth are hard to photograph well: have those looked at in person.
See a doctor promptly if…
Don't wait for any online check, ours included, if a spot:
- is growing, or changing in shape or colour over weeks
- bleeds without being injured, or is a sore that hasn't healed within about 4 weeks
- is new in adulthood and looks different from your other moles
- is a firm, raised bump that keeps getting bigger
- keeps itching, hurting, crusting or oozing
- is a new or widening dark streak under a nail that isn't from an injury
If a spot is bleeding heavily, or a lump is growing by the day, get medical help the same day.
Not sure how urgent it is? Read is this mole an emergency?
Skin cancer checker: common questions
Is there a free AI skin check?
Not on CheckMole: the AI photo check is paid, from $2.99, and the payment page shows every option and whether it renews before you pay. A single check is $4.99, paid once, with no subscription. What is free here is the ABCDE quiz: five questions, about 30 seconds, no photo and no AI; your own answers decide the result. Whatever you use, free or paid, no check can rule skin cancer out.
Can you identify skin cancer from a photo?
Not with certainty. Doctors do use photos to decide who needs to be seen first, and research on AI with dermatoscope images is promising. But a phone photo misses depth, texture and how a spot feels, and lighting shifts colours. A photo can show warning signs worth acting on; a reassuring result cannot rule cancer out. More in how AI skin cancer detection works and where it fails.
Can ChatGPT detect skin cancer?
General chatbots can describe a photo and explain the ABCDE signs, but they are not designed or approved for checking skin, and the answer can change with how you ask. The same basic limit applies to every photo tool, ours included: none of them diagnoses. CheckMole's check follows a fixed process: the same ABCDE description every time, and fixed rules, not a conversation, set the suggested next step.
Is there a free app to identify skin cancer?
No app can identify skin cancer; the useful ones help you decide whether and how soon to see a doctor, and help you track a spot over time. For free, you can use our ABCDE quiz and the body mole map. For how the photo apps compare, see the best mole check apps.
What happens to my photo?
It is resized in your browser and, only after you tick the consent box, sent once to our AI provider (Google's Gemini service) for an automated description. The photo itself is not stored on our servers. Details are in the privacy policy.
Does an online check replace a skin check by a doctor?
No. It can help you decide how soon to get a spot looked at, and keep a dated photo of it. If you have many moles, a family history of melanoma, had skin cancer before or have a weakened immune system, regular checks by a dermatologist matter more than any app. See what a skin cancer screening involves.
Have a spot in mind?
Add a photo and see what the warning signs look like in about a minute. Then, whatever the result, see a doctor if the spot changes, bleeds or doesn't heal.
Check my spotThe AI photo check is paid, from $2.99. It does not diagnose and does not replace a doctor.
Not sure what your spot is? Start here
CheckMole is educational and does not diagnose. If a spot worries you, see a doctor.