What are the tiny ants in my house?

Ants around 1/16 inch are usually pharaoh ants (yellowish, whole body pale), ghost ants (dark head and thorax, see-through pale abdomen and legs), thief ants or little black ants. All prefer sweets and grease, and all are best handled with bait rather than spray.

What are the big black ants in my house?

Large black ants 1/4 to 1/2 inch long are almost always carpenter ants. Look for an evenly rounded top of the thorax and a single node at the waist. Seeing them indoors in late winter or early spring suggests a nest inside the structure.

Are red ants and fire ants the same?

Not always. Fire ants are reddish-brown with a darker abdomen, live in fluffy dirt mounds without a center hole, and sting. Other 'red ants' include harmless field ants, pharaoh ants (pale yellow-red, indoors) and harvester ants (larger, Western, also sting).

Crazy ants run in erratic, jerky paths instead of neat trails. The longhorn crazy ant is common indoors in the South; the invasive tawny (Rasberry) crazy ant forms enormous outdoor populations in Texas, Louisiana and Florida and can short out electrical equipment.

How do I get rid of black ants?

Small black ants in the kitchen (odorous house, little black, pavement) go away with sweet or protein baits on the trail and sealed entry points. Big black ants are carpenter ants and need the nest located and treated.

Types of Ants in the House: ID Guide With Sizes

The most common types of ants in US homes are odorous house ants, pavement ants, Argentine ants, carpenter ants, pharaoh ants and, in the South, ghost ants and fire ants. You can tell most of them apart with four clues: size, color, smell when crushed, and where they nest.

Getting the ID right matters because the treatment differs: most small ants fall to bait on the trail, carpenter ants need their nest found, and pharaoh ants spread if you spray them.

Quick ID table

Ant	Size	Color	Telltale sign	Region
Odorous house ant	1/16–1/8 in	brown to black	rotten-coconut smell when crushed	nationwide
Pavement ant	1/8 in	dark brown-black, pale legs	sand piles along slab cracks	nationwide, esp. North
Argentine ant	1/8 in	light to dark brown	huge steady trails, no smell	CA, Southeast
Little black ant	1/16 in	shiny jet black	tiny, slow trails	East, Midwest
Pharaoh ant	1/16 in	yellow to light red	apartments, bathrooms, hospitals	nationwide indoors
Ghost ant	1/16 in	dark head, pale see-through abdomen	almost invisible on counters	FL, Gulf Coast, HI
Thief ant	1/32–1/16 in	pale yellow	in pantry foods, grease	nationwide
Carpenter ant	1/4–1/2 in	black, or red and black	sawdust piles, night activity	nationwide
Fire ant	1/8–1/4 in, mixed sizes	reddish-brown, dark abdomen	fluffy mounds, burning sting	South, CA
Harvester ant	1/4–1/2 in	red to dark red	bare cleared disk around nest	West, Southwest
Crazy ant	1/8 in	dark, long legs and antennae	erratic running	South
Asian needle ant	1/5 in	dark brown, slender	under mulch and logs, stings	Southeast

Black ants

"Black ants in the house" usually means one of three:

Odorous house ant. Brown-black, 1/8 inch, trails along counters and sink edges. Crush one: a sweet, rotten-coconut odor confirms it. Multi-queen colonies nest in walls, under floors, in potted plants and outside under mulch. The classic "sugar ant"; see sugar ants.
Little black ant. Tiny, glossy jet black, slower than odorous house ants. Nests outdoors in soil and rotting wood, wanders in for sweets and grease.
Pavement ant. Dark brown-black with paler legs and fine parallel grooves on the head (visible with a magnifier). Look for small piles of sand pushed up along sidewalks, driveway cracks and the edge of a basement slab.

Big black ants

Big black ants, 1/4 to 1/2 inch, are almost always carpenter ants. Workers vary in size within a colony. Clues: one node at the waist, a smoothly arched thorax, and ants wandering singly at night rather than in tight trails. Indoors in late winter or spring, they suggest a nest in the house itself. Full guide: carpenter ants.

How to get rid of black ants: small ones go away with bait and sealing (see how to get rid of ants); carpenter ants need nest location and treatment.

Red ants

Fire ants (red imported fire ant): reddish-brown with a darker rear, workers of many sizes in the same mound. Mounds of loose, fluffy soil with no opening on top, often after rain. They sting hard. Found from Texas to the Carolinas, Florida, parts of California and New Mexico. See fire ants.
Harvester ants: larger, red to dark red, in the West and Southwest. Nests sit in a bare, cleared circle of ground with seed husks around the hole. Painful sting; leave them alone or treat if near play areas.
Pharaoh ants: pale yellow-red, tiny, indoors only in most of the US. Nest in wall voids, behind outlets, in appliances. Multi-queen colonies bud into new nests when sprayed. Bait only.
Field ants (Formica): red-and-black, medium-sized, mound-building in lawns and woods. They bite and spray formic acid but rarely come inside.

Tiny ants

Pharaoh, ghost, thief and little black ants all run around 1/16 inch. Ghost ants are named for their translucent pale abdomen and legs, which make them seem to vanish on light counters; they love sweets and nest in potted plants and wall voids in warm states. Thief ants are pale and very small, often found in sealed-looking pantry foods and grease; they also raid other ant nests. All four are bait problems, not spray problems.

Other ants worth knowing

Argentine ant. Light to dark brown, 1/8 inch, no odor when crushed, moves in wide, fast, continuous trails. One of the most important ant pests in California and the Gulf states; colonies link into supercolonies spanning whole neighborhoods. Expect to manage them seasonally with outdoor baits, not eliminate them.

Crazy ants. The longhorn crazy ant (dark, very long legs and antennae, frantic movement) nests indoors in the South and in heated buildings elsewhere. The tawny crazy ant is an outdoor invasive in Texas, Louisiana, Mississippi and Florida that reaches staggering numbers and packs into electrical boxes. Tawny crazy ants generally need professional help.

Asian needle ant. Slender, shiny dark brown, about 1/5 inch with lighter tips on the legs and antennae. Nests in damp wood, under mulch, stones and logs across the Southeast and up to the mid-Atlantic. Its sting can cause allergic reactions, including anaphylaxis in a small number of people.

Acrobat ants. Heart-shaped abdomen they raise over the body when disturbed; nest in damp or previously damaged wood, sometimes in foam insulation. Often confused with carpenter ants.

Big ants vs flying ants vs termites

Big ants with wings in spring are usually carpenter ant or field ant swarmers. Termite swarmers look similar but have straight antennae, a thick waist and four equal-length wings. Compare in flying ants and termites vs ants.

How to identify ants yourself

Collect a few on clear tape or in a zip bag; put them in the freezer for an hour.
Measure against a ruler. Note if workers vary in size (fire ants, carpenter ants) or are uniform (most small house ants).
Look at the waist with a phone macro: one node or two?
Smell test for odorous house ants: crush one and sniff.
Note where they go at night and after rain.

Still stuck? Your county Cooperative Extension office will identify a sample, often for free.

Types of House Ants