Here is a really simple way to tell if one of your moles is getting bigger — even a very tiny dot of a mole.

No apps required! You need only two simple items.

The first is a 3 x 5 index card.

Making Reference Dots for Mole Size Comparison

With a pencil, create a dot on the very edge of the long side of the index card. The size of the dot should be as close as possible to the mole.

This is the baseline dot that should replicate the size of the spot on your skin. Use an index card, rather than regular paper, because the stiffness makes it easier to handle.

Place the edge of the card, that has the dot, against your skin as close to the mole as possible.

This is how you can compare the size of the dot to the mole, to see if you need to make it a tad bigger to match, or, start over and create the dot again to match the size.

The objective is to make a dot that’s the exact size (and shape, if applicable) to the mole. A bigger mole is less likely to appear as a perfect circle.

Duplicating the shape of a non-circular skin lesion will be challenging to the less-artistically inclined. If you can’t draw, do your best, as this is still a great home test.

Next, draw a second dot that’s a tiny bit smaller than the skin spot (or smaller than the baseline-drawn dot), on the edge of the card, near the baseline dot.

Finally, make a third dot, on the other side of the baseline dot, that’s a bit bigger.

Compare the Dots to See if Mole Is Bigger

You now have three dots. The middle dot is the same size as your mole. If you suspect it’s changing in size, all you need to do, to verify this, is place the edge of the card against your skin near the mole.

The closer the dot is to the edge of the card, the easier it will be to make a side by side comparison between mole and dot.

Without this reference point, it will be difficult to determine if your perception that a mole is changing in size is just your imagination. The index card method is objective and leaves nothing to imagination.

If the size of what’s on your skin begins matching the dot that’s bigger than the baseline dot, you know you’re not imagining that your mole has gotten bigger.

If after a week, the mole then matches the size of the baseline dot, this means that it has returned to its original size.

This is exactly what happened to me when I became concerned over a tiny brown spot. Because I was using the dot method, I knew it wasn’t my imagination that the mole had gotten bigger.

After several days of this, it then began matching the baseline dot that I had drawn, which reassured me that the increase in size must have been due to irritation. A biopsy later confirmed this.

Lorra Garrick has been covering medical, fitness and cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.