Spider Identifier: What Spider Is This?

Spider anatomy 101, what to look at on the body

Every spider shares the same basic body plan: two body sections, eight legs, no antennae, no wings, and a pair of fangs. That alone separates spiders from insects, which have three body parts, six legs, and usually wings. Beyond the basics, a handful of features do most of the identification work. Knowing where to look on the body sharpens identification before you even reach for the spider identifier.

Two features in particular separate spider families. One is the eye arrangement, covered below. The other is the silk structures at the tip of the abdomen. Most spiders have three pairs of spinnerets, while recluses have a single unpaired bump visible from below. Body size is harder to use than people think, because leg span can double between a juvenile and an adult of the same species. Use body length only, from the front of the cephalothorax to the tip of the abdomen. For scale, a US quarter is about 24 mm across.

Spider identification checklist

Before you upload a photo to the spider identifier, run through the eight clues below. Even two or three of them usually narrow the spider to a family, and a family plus a region usually narrows it to a species. For the deeper guides, jump to wolf spiders, black widow markings, or brown recluse identification.

Spider identifier chart

The spider identifier chart below covers the nine spiders people photograph most, ordered from harmless to the two that need care. Match the body size and the marking first, then confirm with the web. Venom severity uses the same three levels as the venom section further down. Low means wash and ice, medium means watch it for a week, and high means see a doctor.

Body size is the body only, not the leg span. A US quarter is about 24 mm across, so a wolf spider that looks alarming on a wall is usually a body smaller than a coin.

Spider eyes, count and arrangement

Eyes are one of the best clues to a spider’s family, and they are often easy to photograph head-on. Most spiders have eight eyes in two rows of four. Wolf spiders have three rows with two big eyes in the middle, jumping spiders have two huge front eyes, and recluses have only six, in three pairs.

Our spider eyes guide shows eight eye patterns side by side, explains how to count a spider’s eyes from a phone photo, and covers how well spiders really see, day and night. One trick worth knowing: after dark, a wolf spider’s eyes shine green-white in a flashlight beam.

10 major spider families to know

There are about 54,000 described spider species in 139 families. The 10 families below cover nearly every spider a North American household will see. Each family has its own mix of web style, hunting behavior, and body shape. That mix lets you place an unknown spider into one of these groups in seconds.

Several of these families have their own pages on this site, with photos and look-alikes. See jumping spiders, cellar spiders, hobo spiders, red spiders, and the common house spider.

6 common spiders to compare

These are the spiders most people in North America see indoors. Tap any card for more on threat level and habitat. For close-up markings, see the linked deep-dive pages: wolf spider, black widow, and brown recluse.

Spider webs, what the type tells you

About half of all spider species don't build catching webs at all, they hunt actively or ambush. For the ones that do build webs, the geometry is a near-perfect family-level identifier. Webs are also a useful ID clue when you can't catch a glimpse of the spider itself.

A few practical notes. Black widow webs are often described as "messy" but the silk is unusually strong, if you accidentally walk into one, it feels rubbery, almost like a thin thread of fishing line. Orb webs are fragile by comparison and tear easily. Funnel webs in lawns become highly visible after a heavy dew, when you can see hundreds of them across a single yard.

Small white or dark splats on the wall below a web are the spider’s droppings, and they are often the first sign you notice. Our guide to spider poop explains what they look like, how to tell them from bed bug or mouse droppings, and how to clean them.

Dangerous spiders to know

Only two North American house spiders need extra caution. Both prefer hiding spots, woodpiles, sheds, old boxes, the corner of an attic, and both will bite if pressed against skin. Most other spider species you encounter are either harmless or have venom too mild to matter for healthy adults.

Harmless spiders that often get the blame

Long-legged cellar spiders, jumping spiders, and orb weavers do most of the spider work in a home, they eat flies, mosquitoes, and other pests. They look alarming but rarely bite people, and even a bite is mild. A gentle cup-and-card release outside is usually the right move.

The big spider in a round web by the front door or the porch light is almost always an orb weaver. Our orb weaver guide shows how to tell the common US kinds apart and why they appear in fall. One of the biggest orb weavers in the Southeast is the golden silk orb-weaver, the spider most people there call a banana spider. Its web can be 6 feet wide, yet its bite is milder than a bee sting. Our banana spider guide shows how to tell it from the yellow garden spider. Its invasive cousin from East Asia has a Joro spider guide of its own, with its bite, its US range and when to remove one.

Two harmless species are often mistaken for dangerous ones: the woodlouse hunter (Dysdera crocata) and the false black widow (Steatoda spp.). The woodlouse hunter has a reddish-orange front body and large curved fangs, but its venom is mild and not medically significant. The false widow looks a bit like a true widow. However, it lacks the bright red hourglass and has a duller, mottled brown color. Both eat pest insects and are best left alone or moved outside.

Spider behavior, what they're doing and why

Behavior is one of the easiest clues, because unlike the spider identifier, it needs no photo at all. You just need to watch for a few seconds. Different families hunt in very different ways, and those habits are dead giveaways:

• Sit-and-wait web hunters. Orb weavers and cobweb spiders build a web, then sit in or near it. They're not aggressive; they just want flies. Most don't move much during the day.
• Ambush hunters. Crab spiders sit motionless on flowers, sometimes color-matching the bloom. Trapdoor spiders wait in burrows with hinged silk lids. Wolf spider sometimes uses a hole in the ground for the same purpose.
• Active hunters. Wolf spiders and jumping spiders go to the prey. Wolf spiders run on the ground; jumping spiders stalk, then pounce up to 50 body lengths. Jumping spiders are the only spider family with vision good enough to plan a route around an obstacle.
• Net casters. Net-casting spiders (Deinopidae) hang from silk and hold a small net of elastic silk in their front legs. When prey walks below, the spider throws the net like a fisherman.
• Spitting hunters. Spitting spiders (Scytodidae) shoot a sticky venomous fluid up to 2 cm to glue prey to the ground before delivering a bite. They have six eyes in pairs like recluses.

Some behaviors belong to one sex only. Mature male wolf spiders drum their pedipalps in courtship. Mature male jumping spiders do elaborate dances with their colorful front legs. The spiders you usually see indoors in late summer and early fall are wandering males. They’ve left home to find mates and got lost.

Spider life cycle, egg to adult

All spiders grow through similar stages: egg, spiderling, juvenile, and adult. Unlike beetles or butterflies, they don’t go through complete metamorphosis. Instead, they molt several times as they grow, typically 5–10 times, and get larger with each molt. Each stage between two molts is called an instar. A spider usually can’t regrow a lost leg except by molting, which is why you sometimes see seven-legged spiders.

One striking pattern: most spider species live about a year, and the whole population gets through winter as eggs or juveniles. Tarantulas are the exception. That is one reason they’re popular as pets, since a captive-bred female can live 25 years with the right care. For wolf spider lifespan in detail, see our wolf spider size and biology page.

Spiders by US region

Where you live narrows the possibilities hard. Brown recluses, for example, have a very specific south-central range, most "recluse bites" diagnosed outside that range are something else. Below is a quick regional breakdown of what to expect.

The biggest myth on this list is the brown recluse range. Outside MO/AR/OK/TN/KS/IL/parts of TX/AL/GA, true brown recluses are uncommon to rare. Many states, California especially, have a strong "recluse" rumor that doesn't match the entomological evidence. The state has the desert recluse in its southeastern deserts but not the brown recluse proper. See our brown recluse identification page for the full state-by-state map.

Spider look-alikes, harvestmen, solifuges, and more

Several arachnids look like spiders but aren’t. Knowing the differences keeps you from mistaking something harmless for a dangerous spider.

Two surprises in this table. Harvestmen ("daddy long legs" in the US) are arachnids but not spiders, they have one fused body part, no silk glands, and no venom glands. They can't bite humans. The other surprise: solifuges (camel spiders) get sensational press for their speed and big fangs, but they're not venomous to humans and aren't even spiders. They're a separate arachnid order, Solifugae. Ticks, the arachnids people meet most often after spiders, have their own guide to ticks.

Spider venom 101

Almost all spiders are venomous in the technical sense, because they need venom to subdue prey. But only a small number have venom that matters medically to humans. How strong a bite is depends on the venom’s chemistry, the amount injected, and the size of the person bitten. A black widow injects only about 0.02 mg of venom, but that venom is alpha-latrotoxin, a powerful neurotoxin. A wolf spider’s venom is much weaker and barely registers.

A few important caveats. Children, older adults, and people with weak immune systems can react more strongly to bites that healthy adults would barely notice. An allergic reaction is also possible after any spider bite, even from species without medically significant venom. Get medical care if you see hives, swelling that spreads beyond the bite, changes in breathing, or symptoms that last beyond 48 hours.

Spider bite first aid

Most reports of spider bites turn out to be something else, bed bugs, mosquitoes, fleas, MRSA infections, or contact dermatitis. A true spider bite is uncommon, and it almost always involves a spider that was pressed against skin (rolled on in bed, trapped in clothing). Here's the standard at-home approach for a confirmed minor bite:

1. Wash the area with soap and warm water to reduce infection risk.
2. Apply a cool compress for 10–15 minutes to reduce swelling and itching.
3. Elevate the limb if the bite is on an arm or leg.
4. Take an over-the-counter antihistamine for itching, and a non-aspirin pain reliever if needed.
5. Photograph the spider if you can do so safely. Identification helps the doctor if symptoms develop.
6. Monitor for 48 hours: most bites resolve. Spreading redness, fever, severe pain, or a blistering lesion need medical attention.

For a deeper breakdown of bite patterns and how to tell different bites apart, see our bug bite identification guide.

Spider myths, what people get wrong

Spiders attract more folklore than almost any other animal. A surprising amount of "common knowledge" about them turns out to be invented. Here are the most-repeated ones, and the actual facts.

• Myth 1

  Myth: “Daddy long legs are the most venomous spider in the world but their fangs can't pierce skin.”

  Truth: False on both counts. Cellar spiders have mild venom that's nothing remarkable. MythBusters (2004) had a cellar spider bite a volunteer, barely felt.

• Myth 2

  Myth: “Brown recluses live everywhere in the US.”

  Truth: Their range is south-central US (MO, AR, OK, TN, KS, IL, parts of TX, AL, GA). Most 'recluse bites' diagnosed outside that range are actually MRSA, allergic reactions, or other infections.

• Myth 3

  Myth: “You swallow 8 spiders a year in your sleep.”

  Truth: Pure fabrication. Traced to a 1993 magazine column written specifically to show how easily false 'facts' spread. Spiders avoid breathing humans.

• Myth 4

  Myth: “All spiders build webs.”

  Truth: Only about half. Wolf, jumping, crab, sac, and many other families hunt actively or ambush without using a web at all.

• Myth 5

  Myth: “Spiders come inside in fall because it's cold.”

  Truth: Many indoor spiders live indoors year-round. The fall 'invasion' is usually adult males wandering to find mates, not refugees from the cold.

• Myth 6

  Myth: “Bigger spider = more dangerous.”

  Truth: Wolf spiders and tarantulas are large but mildly venomous. The black widow is small, the brown recluse smaller. Body size is no guide to venom strength.

• Myth 7

  Myth: “Spider eggs can hatch in a wound.”

  Truth: False. Spiders don't lay eggs in mammals. Stories of 'spider eggs hatching under skin' are urban legends. The few invertebrates that do this (some bot flies, certain mites) are not spiders.

• Myth 8

  Myth: “Spiders are insects.”

  Truth: Spiders are arachnids, not insects. Insects have 6 legs and 3 body parts; spiders have 8 legs and 2 body parts (cephalothorax + abdomen).

Spider identifier by picture: how to shoot a usable photo

A good photo for the spider identifier shows the body, the legs, and ideally the underside. Use these tips before you search:

1. Don’t get close. Use the zoom on your phone and shoot from a safe distance.
2. Light the subject. Move closer to a window, or shine a flashlight from above.
3. Capture the underside if safe. The red hourglass on a widow is on the bottom.
4. Show scale. Place a coin or a pen nearby for size context.
5. Crop tight on the body before you upload it to the spider identifier.

When you’re ready, use the free spider identifier at the top of this page and upload the photo. The spider identifier returns the most likely species with confidence levels. For natural-language questions, see what bug is this? or our bug identifier by picture guide.

How to reduce spiders indoors

Spiders move into homes where they find prey, harborage, and easy entry. Removing those three reduces the indoor population over a season more reliably than swatting or spraying.

• Vacuum corners, baseboards, and behind furniture monthly. Pay special attention to ceiling corners and behind doors.
• Seal gaps around windows, doors, vents, and pipes. Even a 1.5 mm gap is wide enough for many adult spiders.
• Replace outdoor white bulbs with yellow “bug” bulbs, they attract fewer insects, so fewer spiders.
• Keep firewood, leaves, and stored boxes at least 10 feet from the house wall.
• Run a dehumidifier in basements. Most spider prey (booklice, silverfish, drain flies) needs moisture to thrive.
• Wear gloves when moving stored boxes in an attic, garage, or shed. Most widow and recluse bites happen when a hand goes into an undisturbed space.
• Don't pile dirty laundry on the floor for days, both widows and recluses occasionally hide in clothing.
• Shake out shoes left in garages or sheds before putting them on. Recluses sometimes hide in shoes.

Pest control disclaimer. Photo-based identification can help, but it is not always perfect. For dangerous spiders, large infestations, or anything you are unsure about, contact a licensed pest control professional.