Reviewed by Evan Lewis, PhD. Last updated August 2026.
Whether it's a corn or a wart on your foot comes down to three things you can check yourself. A wart usually has tiny black dots, breaks up the skin lines running across it, and hurts most when you squeeze it from the sides. A corn has no dots, keeps the skin lines, and hurts when you press straight down on it.
A corn is pressure. A wart is a virus. Everything else follows from that.
What is the actual difference between a corn and a wart?
A corn is your own skin thickening up where something presses or rubs. A wart is an infection of the skin by human papillomavirus, and the virus makes the skin cells pile up into a rough lump. One is mechanical. The other is viral.
That single difference is why the two behave so differently, and it's why the home checks below work. A corn forms over a bony point because that's where the pressure lands. A wart turns up wherever the virus got in, which might be a pressure point and might be nowhere near one.
Corn vs wart: the full comparison
| Corn | Wart (verruca) | |
|---|---|---|
| What causes it | Pressure and friction, usually footwear or a bone underneath | Human papillomavirus in the top layers of skin |
| Black dots | None | Usually visible. They're tiny clotted blood vessels |
| Skin lines | Run straight over the top of it | Stop at the edge. The pattern is broken |
| Squeeze it side to side | Not especially sore | Usually the worst pain |
| Press straight down | Usually the worst pain | Less sore than the squeeze |
| Surface | Smooth and waxy, with a hard translucent centre | Rough and grainy, often with a raised rim |
| Where it turns up | Pressure points only. Toe tops, little toe, ball of the foot, heel | Anywhere on the sole or toes, pressure point or not |
| How many | Usually one or two, in matching spots | One, or a scattered cluster that grows over time |
| Contagious | No | Yes, by contact and by damp shared floors |
| What changes it | Taking the pressure off, plus professional debridement | Time and your own immune system, plus what a clinician decides |
Does it have black dots?
Look at it in daylight, and if there's dead skin on top, file it back gently first. Warts have a blood supply of their own. Those vessels get pinched and clot, and they show through the surface as pinpoint black or dark red dots.
A 2023 dermoscopy study of 70 patients found black or red dots in 100% of the warts examined and in none of the corns or calluses. That's about as clean a split as you get in skin.
Corns have no blood supply of their own. The centre is a plug of hard keratin, and it looks translucent or waxy rather than dotted.
Do your skin lines run over it, or stop at it?
This is the tell almost nobody knows about, and it's the most reliable one you can do at home.
The soles of your feet have ridge patterns, the same as your fingerprints. A corn or a callus is that skin getting thicker, so the lines keep going right across the lump. A wart replaces the skin, so the ridge pattern stops dead at its border and picks up again on the other side.
In the same 2023 study, skin lines stayed intact in every callus examined, and were interrupted in every wart. Get good light, get close, and follow one line into the lump with your eye. If it comes out the other side, you're probably looking at pressure skin.
Does it hurt more when you squeeze it or when you press it?
Squeeze it gently from the sides, like you're pinching it. Then press straight down on the top with your thumb. Compare the two.
DermNet, the dermatology reference used by clinicians worldwide, puts it plainly: tenderness is worst with lateral pressure for a plantar wart, while a corn or callus is more tender with direct pressure.
The reason is structural. A wart sits in the skin with nerve endings around its edges, so squeezing distorts it. A corn's hard core points downwards into the tissue, so pressing drives it in like a stone in your shoe.
Use gentle pressure. This is a check, not a stress test.
Where on your foot is it?
Corns are predictable. They form where a bone underneath meets a shoe on top, and the same handful of spots come up over and over: the outside of the little toe, the top of a bent toe, the web between the fourth and fifth toes, and under the ball of the foot.
They're common, too. A review in StatPearls puts the prevalence at 14 to 48% depending on the population studied, with older adults more affected as the fat pad under the foot thins out.
Warts have no such map. They turn up on the arch, the instep, the side of the heel, anywhere. If your lump is somewhere no shoe presses, that alone makes a corn unlikely.
Could it be a callus instead of either?
Often, yes. A callus is thickened skin spread over a wider area, with soft edges and no hard central core. It's usually painless. A corn is the concentrated version of the same thing, small and deep with a core that hurts.
People also get caught out by seed corns, which are tiny discrete plugs that often come in clusters on the sole and get mistaken for a patch of small warts. The skin lines and the missing black dots sort those out too. We go through all three side by side in plantar wart vs corn vs callus.
What actually changes each one
Here's the honest version, because it decides what you do next.
A corn goes when the pressure goes. Nothing in a bottle removes a corn, ours included. Change what's pressing on it, and have a chiropodist or podiatrist take the bulk down every few weeks if it's painful. The corn comes back if the pressure comes back. That isn't a failure of a product, it's the nature of the thing.
What you can look after is the skin. The skin around and under a corn takes a beating, and it takes more of one after somebody has pared it down. Keeping it clean and in good condition is the part that's genuinely in your hands, and it's where Sole Shield fits. Two ingredients, iodine and water, sprayed on feet and into shoes. No alcohol, no sting, no staining on skin or socks. It doesn't touch the corn. It looks after the skin the corn lives in.
A wart is a different job. Warts are viral, they often clear on their own given time, and how fast depends largely on your own immune system. DermNet reports that in children, 50% of warts are gone within six months and 90% within two years, with adults generally slower. Anything you do sits alongside that, not instead of it. Our research lead has written on elemental iodine in this area in his white paper on wart and fungal nail management if you want the technical version.
The reason identification matters is that people buy the wrong thing on a guess. A medicated corn pad on a wart, or a wart product on a corn, at best does nothing. At worst you burn the healthy skin around it, which is a common way to turn a small annoyance into a sore foot.
When to stop guessing and get it looked at
Some things are worth a professional eye rather than a home check:
- It bleeds, weeps, or has broken open
- It's changing shape, size or colour
- It hurts enough to change how you walk
- There are several and they're spreading
- You have diabetes, poor circulation, or reduced feeling in your feet
That last one isn't a formality. The NHS is direct about it: if you have diabetes, circulation problems, a weakened immune system, or you're older, don't try to treat corns and calluses yourself. Book a foot care professional instead.
And whichever it turns out to be, don't cut it out with clippers or a blade. That one shows up in foot forums constantly, and it usually ends with a hole in the foot and a longer problem than the one you started with.
Common questions
How can you tell the difference between a wart and a corn?
Check three things. Warts usually show tiny black dots, break the skin line pattern running across them, and hurt most when squeezed from the sides. Corns have no dots, keep the skin lines running over the top, and hurt most when pressed straight down. Corns also only form on pressure points, while warts turn up anywhere.
Is a corn and a wart the same thing?
No. A corn is your own skin thickening in response to pressure and rubbing, so it isn't contagious and it won't spread. A wart is caused by human papillomavirus infecting the skin, so it can spread to other spots on your foot and to other people, particularly on damp shared floors.
Do corns have black dots?
No. Black dots are tiny clotted blood vessels feeding a wart, and corns have no blood supply of their own. A corn's centre is a plug of hard keratin, which looks translucent or waxy. In a 2023 dermoscopy study, black or red dots appeared in every wart examined and in none of the corns or calluses.
What is the pinch test for a corn or wart?
Squeeze the lump gently from the sides, then press straight down on it, and compare. Warts are typically more painful on the side-to-side squeeze, because pressure distorts the lesion. Corns are typically more painful on direct downward pressure, because the hard core is driven into the tissue underneath. Use light pressure.
Can a corn turn into a wart?
No. They're unrelated. A corn is mechanical and a wart is viral, so one doesn't become the other. What does happen is that a wart on a pressure point builds callus around itself, which can make it look exactly like a corn. That's one of the commonest reasons people get it wrong.
Do warts on the foot go away on their own?
Often, given time. DermNet reports that in children, around 50% of warts clear within six months and 90% within two years. Adults tend to be slower, and people with a weakened immune system slower still. If it's painful, spreading, or you aren't sure what it is, get it looked at rather than waiting.
Should I use a corn plaster if I'm not sure?
Better not to. Medicated corn plasters and wart products both act on the skin around the lesion as well as the lesion itself, and applied to the wrong thing they can burn healthy skin. Work out what you're dealing with first. If you can't tell, a chiropodist or podiatrist will know in seconds.
The bottom line
Black dots and skin lines will settle most of these at home. The squeeze-versus-press check settles most of the rest. If all three point the same way, you have your answer.
And if they don't, that's useful information too. It means this one is worth showing to somebody who looks at feet all day.
Next: how to do the pinch test properly, what a seed corn is, and why the little toe gets more corns than any other.
Evan Lewis, PhD, specializes in natural and nutritional therapies for the prevention and management of chronic diseases and their complications. His research spans chronic disease, diabetes complications, clinical nutrition, and nerve health, including the development of topical iodine therapy for foot care and wound health. IodinePure products are listed with Health Canada as cosmetics. This article is for identification and general information, and it is not a diagnosis. Sources: Patil S, Borkar M, Pande S, Meshram K, Oke M. Dermoscopic Findings in Clinically Diagnosed Cases of Plantar Warts, Corns, and Calluses. Cureus. 2023;15(4):e38093. DermNet, Viral wart. StatPearls, Corns. NHS, Corns and calluses.
