Cutting and joining LED strip lights

Yes, you can cut an LED strip - at the marked cut points only, where a pair of copper pads is exposed. You can rejoin the pieces, and the offcut still works. All of that depends on one purchase people make wrong: the connector has to match your strip's pin count AND its width in millimeters, and it has to be the right kind - strip-to-strip to rejoin a run, strip-to-wire to feed power in somewhere new.

The cutting itself takes a pair of scissors and ten seconds. Everything that goes wrong goes wrong afterwards, and almost always for the same reason: a 10mm four-pin connector was bought for a 12mm five-pin strip, or a gapless strip-to-strip clip was bought when what the job needed was a wire back to the driver.

Widths in that table are the common cases on the strips these connectors are sold for, and they are not a rule - 8mm RGBW strips and 10mm RGBW strips both exist. Measure the strip with a ruler before you order, because a connector one millimeter out simply will not close on it.

A strip is a long chain of short circuits in series, not one continuous circuit. Each link - usually three LEDs on a 12V strip, six on a 24V one - has its own current limiting resistor, and the cut points sit at the boundary between links.

Cut on the line, through the pads. The marked point is a pair of copper pads with a printed line, often a scissor icon, across the middle. Cutting there leaves half the pad on each side, which is exactly what a connector needs to grip.

Cutting between marks kills that segment. Not the whole strip, and not permanently in any dramatic sense - the segment you cut through will never light again, and the rest works. It is an irreversible three-LED tax on a careless cut.

The spacing decides how precise you can be. This is the practical argument people miss when choosing between 12V and 24V strips. A 24V strip cuts at roughly twice the interval, so on a short cabinet run you may be forced to leave an inch of dark or buy a shorter strip. On a long run the same property is a virtue.

Every pick on this page is a solderless clip, and that is the right default for the work this site is about - a strip going under a cabinet, into a cove or along a shelf, in a dry place, once. It is worth being honest about what the clip is doing, though.

A clip is a sprung contact pressed onto a flat copper pad. It carries current as long as that pressure holds. Solder is a metallurgical join: once it is made, there is no pressure to lose. Everything that makes clips fail is a pressure problem - the strip gets flexed, the adhesive lets go and the strip hangs off the clip, the contact oxidizes, or the housing was never closed hard enough in the first place.

So the rule we would apply: clips for a run that gets fitted and left alone; solder for anything that moves, gets warm, or lives somewhere you would hate to take apart. On an addressable strip the case for solder is stronger again, because a data line is less tolerant of a marginal contact than a power line is - a flickering or color-scrambled run past a joint is usually that.

Five connectors covering the five jobs. These are not ranked against each other - each one fits a different strip or solves a different problem, and buying the wrong one is the single most common mistake in this whole category.

Feeding power to a cut single-color strip - HitLights 2 pin 8mm strip-to-wire. Strip-to-wire clips for 8mm single-color tape, twelve to a pack, with the screwdriver these need included. This is the connector for the offcut problem - the piece with no plug on it.
Who it is for: anyone who cut a run and wants the second piece lit. Who should skip it: anyone rejoining two pieces end to end, who wants strip-to-strip instead.
Cons: 8mm single color only; no amp rating published; the contacts are the failure point if the strip is flexed afterwards.

Rejoining a cut RGB run - LightingWill 4 pin 10mm gapless. Strip-to-strip clips for 10mm RGB tape, gapless so the joint does not leave a dark section mid-run, ten to a pack and the cheapest connector here.
Who it is for: putting a 5050 RGB strip back together after cutting to length. Who should skip it: anyone with an RGBW strip - five conductors will not go into four contacts.
Cons: unwired, so it cannot feed power in; gapless clips hold the two strips under tension and pop off a tight corner; no amp rating published.

Turning a corner - JAUHOFOGEI 2 pin 8mm L-shape. Right-angle clips rated to 5A, which is the only published amp figure among these five. A strip bent around a 90 degree corner cracks its copper eventually; an L-clip means you cut and turn instead.
Who it is for: an L-shaped kitchen run, or a cove that turns. Who should skip it: anyone whose corner is not square - a fixed 90 degree clip cannot help, and a short wire can.
Cons: 8mm single color only; bulkier than a straight join and visible under a shallow cabinet lip; ten to a pack, which is more corners than most kitchens have.

Addressable strips - BTF-LIGHTING 3 pin 10mm kit. A kit rather than one clip type: gapless joins, eight corner connectors and four 5.9 inch extension wires, from the brand that makes the strips. It names the chipsets it supports - WS2812B, WS2811, SK6812 - which on an addressable strip matters more than width does.
Who it is for: anyone cutting a strip whose LEDs are individually controlled. Who should skip it: plain single-color or RGB runs, where a 3-pin clip has nothing to connect to.
Cons: addressable strips are directional, so a clip fitted backwards gives you nothing downstream; a sprung contact on a data line is the least reliable place to use one; no amp rating published.

RGBW strips - BTF-LIGHTING 5 pin 12mm kit. The same kit format for 12mm five-conductor RGBW tape, with the width published in both millimeters and inches so you can measure before ordering.
Who it is for: an RGBW or RGBCCT strip, where the white is a real diode rather than mixed. Who should skip it: anyone with a 10mm RGBW strip - those exist and this will not fit.
Cons: five contacts means five chances for one to sit proud and drop a channel; more connector than a single straight join needs; no amp rating published.

A joined run that dims towards the far end is usually not a bad joint. It is a run that is now longer than its supply, and the symptom is gradual rather than sudden.

This is also the honest limit of what any of this achieves. A cut-and-joined strip is still the same strip: it does not get brighter, and the lumen figure on the box was for the whole reel. If the run was never bright enough for the job, see strip vs puck vs bar before spending more on connectors - a strip is frequently the wrong format rather than the wrong length.

Cut with scissors, square across the line. An angled cut leaves one pad shorter than the other and the clip grips unevenly. Side cutters crush the tape; scissors are better here.

Check polarity before you close the clip. Strips print + and - at every cut point, and the clip has a fixed orientation. On single-color strips a reversed clip simply does not light; on addressable strips it lights everything up to the joint and nothing past it.

Close the housing fully, then tug the strip. A clip that opens under a gentle pull was never closed. This is a ten second test that saves taking a cabinet apart later.

Mount both sides of the joint. The clip should never be carrying the weight of unmounted strip - see the warning above, since this is what actually fails.

Leave the offcut attached to nothing until you have a plan. Exposed pads on a live circuit are a short waiting to happen. If the second piece is not going in today, cap it or leave it unpowered.