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The sink drain guide

Sink drains: pick the right one, fit it, fix it

Three things decide which drain fits: the size of the hole in the sink, whether the bowl has an overflow, and the pipe size below. Kitchen sinks almost always take a 3-1/2 inch basket strainer on 1-1/2 inch pipe. Bathroom sinks take a 1-1/4 inch pop-up, with or without overflow to match the bowl.

Find my drain Size chart

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BASKET STRAINERTAILPIECESLIP NUTJ-BENDTRAP ARM2 TO 4 IN
Fig. 1 Under a kitchen sink: strainer, tailpiece, and a P-trap holding a 2 to 4 inch water seal.
01

Start with your sink

The sink decides the drain. Pick yours for the types that fit, the sizes to check, and what to buy.

3-1/2 in hole / 1-1/2 in pipeKitchen sinkBasket strainers, push-down strainers and disposal flanges.1-1/4 in pipe / overflowBathroom sinkLift rod and push button pop-up drains, with or without overflow.No overflow / long bodyVessel sinkUmbrella and push button drains for bowls that sit on the counter.Always openNo stopper neededGrid drains for vessel, bar and utility sinks that never hold water.
02

Three things that must match

Get these right and almost any drain in the right category will fit. Get one wrong and it leaks, wobbles or will not seal.

  1. The hole in the sink

    Most US kitchen sinks have a 3-1/2 inch opening. Bathroom sink holes vary, roughly 1-1/4 to 1-3/4 inches, so measure across the hole with the old drain out. Size guide.

  2. Overflow or no overflow

    A bowl with an overflow hole needs a drain body with slots for that water. A bowl without one needs a solid body, or water leaks out of the slots when the stopper is shut. VIGO explains the pairing.

  3. The pipe below

    Bathroom drains run 1-1/4 inch pipe and kitchen drains 1-1/2 inch. The P-trap under it holds a water seal that the International Plumbing Code sets at 2 to 4 inches deep. ICC.

03

Find the right drain

Four taps: sink, overflow, hole size and finish. You get the drain type, what to check on the box, and two Amazon searches already filtered for your finish.

1 What kind of sink?
2 Is there an overflow hole near the rim?
3 How wide is the drain hole?
4 Finish

Your drain

04

Sink drain sizes at a glance

Two different numbers get called the drain size: the hole in the sink and the pipe under it. Here is each one, drawn to scale and in a table.

1-1/4 INBATHTAILPIECE1-1/2 INKITCHENTAILPIECEABOUT 1-3/4 INBATHSINK HOLE3-1/2 INKITCHENSINK HOLE0123456789IN
Fig. 2 Pipe and hole sizes drawn to the same scale. Bathroom holes vary, so the dashed circle is a typical size, not a standard.

Sink drain sizes at a glance

PartTypical sizeWhat to knowSource
Bathroom sink tailpiece1-1/4 inThe pipe under a bathroom (lavatory) sink drain. Its P-trap is 1-1/4 in too.Source
Kitchen sink tailpiece1-1/2 inThe pipe under a kitchen basket strainer or disposal. Its P-trap is 1-1/2 in.Source
Kitchen sink drain hole3-1/2 inThe usual US kitchen opening. Some strainers are made to cover 3-1/2 to 4 in.Source
Bathroom sink drain holeAbout 1-1/4 to 1-3/4 inThere is no single standard. Measure the hole and match the range on the drain box.Source
P-trap water seal2 to 4 in deepThe International Plumbing Code calls for a seal of at least 2 in and no more than 4 in.Source
Vessel sink drainBowl hole plus counterUsually no overflow. Needs a body long enough for the bowl and counter together.Source

Measure yours with the drain size tool.

05

Fix a drain

Clogs, slow drains, smells and stuck stoppers, plus step-by-step replacement guides. Each one starts with the gentlest fix.

TAILPIECEJ-BENDTRAP ARMGREASE AND FOODFix a drainUnclog a kitchen sinkOVERFLOWSTOPPERPIVOT NUTPIVOT RODLIFT RODCLEVISHAIR AND SOAPTAILPIECE 1-1/4 INFix a drainUnclog a bathroom sinkTAILPIECEJ-BENDTRAP ARM2 TO 4 INFix a drainFix a slow sink drainOVERFLOWSTOPPER LIFTS OUTPIVOT NUT OFFLIFT RODCLEVISHAIR AND SOAPTAILPIECE 1-1/4 INFix a drainRemove a sink stopperBASKET STRAINERTAILPIECESLIP NUTJ-BENDTRAP ARMNO WATER SEALFix a drainSink drain smellsBASKET STRAINERTAILPIECESLIP NUTJ-BENDTRAP ARM2 TO 4 INMOSTLY CO2 FOAMFix a drainBaking soda and vinegar3-1/2 INSTRAINER BASKETFLANGE BODYPUTTY OR SILICONESINK DECKRUBBER GASKETFRICTION RINGLOCKNUTCOUPLING NUTTAILPIECE 1-1/2 INInstallReplace a kitchen sink drainOVERFLOWSTOPPERPIVOT NUTPIVOT RODLIFT RODCLEVISTAILPIECE 1-1/4 INInstallReplace a bathroom sink drainVENTP-TRAPINTO THE WALL, VENTEDSIPHONS-TRAPINTO THE FLOORInstallS-trap vs P-trap
06

Shop by part

Straight to current listings. Read the matching guide first if you are not sure what fits.

07

Questions people ask

What size is a sink drain?

Bathroom sinks use a 1-1/4 inch tailpiece and trap; kitchen sinks use 1-1/2 inch. The hole in the sink is a different number: about 3-1/2 inches in most US kitchen sinks, and roughly 1-1/4 to 1-3/4 inches in bathroom sinks, where there is no single standard. Measure the hole before you buy.

Do I need a drain with or without overflow?

Match the sink. If the bowl has a small overflow hole near the rim, buy a drain body with overflow slots so that water can escape. If there is no overflow hole, buy a drain without overflow, or water can leak out of the slots when the stopper is closed.

What is the difference between a pop-up drain and a grid drain?

A pop-up drain has a stopper that closes to hold water, worked by a lift rod or by pressing the cap. A grid drain is a fixed strainer with no stopper, so the sink cannot hold water. Grid drains are common on vessel and bar sinks.

Why does my sink drain smell?

Usually because bacteria in the slime lining the drain and overflow give off hydrogen sulfide, or because a sink that is rarely used has lost the water seal in its P-trap. Run water to refill the trap and clean the stopper and overflow.

Is it hard to replace a sink drain yourself?

A kitchen basket strainer or bathroom pop-up is a manageable job with basic tools and an hour or two. The fiddly parts are breaking loose an old locknut and getting the seal right. If the pipes in the wall are corroded or leaking, call a plumber.

Sources: HomeGuide, Hunker, Houzer, ICC, Mr. Rooter. We have not tested these products; see how we choose.