Skip to content
📦 Now offering free US ground shipping on orders of $149 or more. Some restrictions apply, click for details. 📦
📦 Free US ground shipping on $149 or more. Click for details.📦

Internal PVC Coupling

Add length to an existing piece of PVC pipe easily with the FORMUFIT Internal Coupling. This coupling connects two Sch. 40 PVC pipe segments internally, with only a minuscule seam exposed. Internal Couplers are quintessential for breakpoints in larger applications and designs to help reduce transport size, or you can use them to create 10-foot lengths from our 40-inch or 60-inch PVC pipe segments without paying expensive freight.

Available Sizes

FORMUFIT PVC External Couplers are available to buy online in the 1/2", 3/4", 1", 1-1/4" PVC Sizes and fit standard Schedule 40 PVC size pipe only. For sizing information, please see our PVC 101 page.

  • Original price $1.89 - Original price $1.89
    Original price
    $1.89
    $1.89 - $1.89
    Current price $1.89

    1/2 in. Internal Furniture Grade PVC Coupling - White

    FORMUFIT 1/2" Internal Couplings in White connect two segments of 1/2 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden con...

    View full details
    Original price $1.89 - Original price $1.89
    Original price
    $1.89
    $1.89 - $1.89
    Current price $1.89
  • Sold out
    Original price $2.39 - Original price $2.39
    Original price
    $2.39
    $2.39 - $2.39
    Current price $2.39

    1/2 in. Internal Furniture Grade PVC Coupling - Black

    FORMUFIT 1/2" Internal Couplings in Black connect two segments of 1/2 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden con...

    View full details
    Original price $2.39 - Original price $2.39
    Original price
    $2.39
    $2.39 - $2.39
    Current price $2.39
    Sold out
  • Original price $2.39 - Original price $2.39
    Original price
    $2.39
    $2.39 - $2.39
    Current price $2.39

    1/2 in. Internal Furniture Grade PVC Coupling - Gray

    FORMUFIT 1/2" Internal Couplings in Gray connect two segments of 1/2 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden conn...

    View full details
    Original price $2.39 - Original price $2.39
    Original price
    $2.39
    $2.39 - $2.39
    Current price $2.39
  • Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49

    1/2 in. Internal Furniture Grade PVC Coupling - Red

    FORMUFIT 1/2" Internal Couplings in Red connect two segments of 1/2 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden conne...

    View full details
    Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49
  • Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49

    1/2 in. Internal Furniture Grade PVC Coupling - Orange

    FORMUFIT 1/2" Internal Couplings in Orange connect two segments of 1/2 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden co...

    View full details
    Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49
  • Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49

    1/2 in. Internal Furniture Grade PVC Coupling - Yellow

    FORMUFIT 1/2" Internal Couplings in Yellow connect two segments of 1/2 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden co...

    View full details
    Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49
  • Sold out
    Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49

    1/2 in. Internal Furniture Grade PVC Coupling - Green

    FORMUFIT 1/2" Internal Couplings in Green connect two segments of 1/2 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden con...

    View full details
    Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49
    Sold out
  • Original price $2.19 - Original price $2.19
    Original price
    $2.19
    $2.19 - $2.19
    Current price $2.19

    1/2 in. Internal Furniture Grade PVC Coupling - Blue

    FORMUFIT 1/2" Internal Couplings in Blue connect two segments of 1/2 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden conn...

    View full details
    Original price $2.19 - Original price $2.19
    Original price
    $2.19
    $2.19 - $2.19
    Current price $2.19
  • Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49

    1/2 in. Internal Furniture Grade PVC Coupling - Purple

    FORMUFIT 1/2" Internal Couplings in Purple connect two segments of 1/2 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden co...

    View full details
    Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49
  • Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49

    1/2 in. Internal Furniture Grade PVC Coupling - Pink

    FORMUFIT 1/2" Internal Couplings in Pink connect two segments of 1/2 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden conn...

    View full details
    Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49
  • Original price $2.29 - Original price $2.29
    Original price
    $2.29
    $2.29 - $2.29
    Current price $2.29

    3/4 in. Internal Furniture Grade PVC Coupling - White

    FORMUFIT 3/4" Internal Couplings in White connect two segments of 3/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden con...

    View full details
    Original price $2.29 - Original price $2.29
    Original price
    $2.29
    $2.29 - $2.29
    Current price $2.29
  • Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49

    3/4 in. Internal Furniture Grade PVC Coupling - Black

    FORMUFIT 3/4" Internal Couplings in Black connect two segments of 3/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden con...

    View full details
    Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49
  • Sold out
    Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49

    3/4 in. Internal Furniture Grade PVC Coupling - Gray

    FORMUFIT 3/4" Internal Couplings in Gray connect two segments of 3/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden conn...

    View full details
    Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49
    Sold out
  • Original price $2.79 - Original price $2.79
    Original price
    $2.79
    $2.79 - $2.79
    Current price $2.79

    3/4 in. Internal Furniture Grade PVC Coupling - Red

    FORMUFIT 3/4" Internal Couplings in Red connect two segments of 3/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden conne...

    View full details
    Original price $2.79 - Original price $2.79
    Original price
    $2.79
    $2.79 - $2.79
    Current price $2.79
  • Sold out
    Original price $2.79 - Original price $2.79
    Original price
    $2.79
    $2.79 - $2.79
    Current price $2.79

    3/4 in. Internal Furniture Grade PVC Coupling - Orange

    FORMUFIT 3/4" Internal Couplings in Orange connect two segments of 3/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden co...

    View full details
    Original price $2.79 - Original price $2.79
    Original price
    $2.79
    $2.79 - $2.79
    Current price $2.79
    Sold out
  • Original price $2.79 - Original price $2.79
    Original price
    $2.79
    $2.79 - $2.79
    Current price $2.79

    3/4 in. Internal Furniture Grade PVC Coupling - Yellow

    FORMUFIT 3/4" Internal Couplings in Yellow connect two segments of 3/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden co...

    View full details
    Original price $2.79 - Original price $2.79
    Original price
    $2.79
    $2.79 - $2.79
    Current price $2.79
  • Sold out
    Original price $2.79 - Original price $2.79
    Original price
    $2.79
    $2.79 - $2.79
    Current price $2.79

    3/4 in. Internal Furniture Grade PVC Coupling - Green

    FORMUFIT 3/4" Internal Couplings in Green connect two segments of 3/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden con...

    View full details
    Original price $2.79 - Original price $2.79
    Original price
    $2.79
    $2.79 - $2.79
    Current price $2.79
    Sold out
  • Original price $2.79 - Original price $2.79
    Original price
    $2.79
    $2.79 - $2.79
    Current price $2.79

    3/4 in. Internal Furniture Grade PVC Coupling - Blue

    FORMUFIT 3/4" Internal Couplings in Blue connect two segments of 3/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden conn...

    View full details
    Original price $2.79 - Original price $2.79
    Original price
    $2.79
    $2.79 - $2.79
    Current price $2.79
  • Sold out
    Original price $2.79 - Original price $2.79
    Original price
    $2.79
    $2.79 - $2.79
    Current price $2.79

    3/4 in. Internal Furniture Grade PVC Coupling - Pink

    FORMUFIT 3/4" Internal Couplings in Pink connect two segments of 3/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden conn...

    View full details
    Original price $2.79 - Original price $2.79
    Original price
    $2.79
    $2.79 - $2.79
    Current price $2.79
    Sold out
  • Original price $2.79 - Original price $2.79
    Original price
    $2.79
    $2.79 - $2.79
    Current price $2.79

    3/4 in. Internal Furniture Grade PVC Coupling - Purple

    FORMUFIT 3/4" Internal Couplings in Purple connect two segments of 3/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden co...

    View full details
    Original price $2.79 - Original price $2.79
    Original price
    $2.79
    $2.79 - $2.79
    Current price $2.79
  • Original price $2.39 - Original price $2.39
    Original price
    $2.39
    $2.39 - $2.39
    Current price $2.39

    1 in. Internal Furniture Grade PVC Coupling - White

    FORMUFIT 1" Internal Couplings in White connect two segments of 1 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden connect...

    View full details
    Original price $2.39 - Original price $2.39
    Original price
    $2.39
    $2.39 - $2.39
    Current price $2.39
  • Original price $2.59 - Original price $2.59
    Original price
    $2.59
    $2.59 - $2.59
    Current price $2.59

    1 in. Internal Furniture Grade PVC Coupling - Black

    FORMUFIT 1" Internal Couplings in Black connect two segments of 1 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden connect...

    View full details
    Original price $2.59 - Original price $2.59
    Original price
    $2.59
    $2.59 - $2.59
    Current price $2.59
  • Original price $2.59 - Original price $2.59
    Original price
    $2.59
    $2.59 - $2.59
    Current price $2.59

    1 in. Internal Furniture Grade PVC Coupling - Gray

    FORMUFIT 1" Internal Couplings in Gray connect two segments of 1 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden connecti...

    View full details
    Original price $2.59 - Original price $2.59
    Original price
    $2.59
    $2.59 - $2.59
    Current price $2.59
  • Original price $2.89 - Original price $2.89
    Original price
    $2.89
    $2.89 - $2.89
    Current price $2.89

    1 in. Internal Furniture Grade PVC Coupling - Red

    FORMUFIT 1" Internal Couplings in Red connect two segments of 1 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden connectio...

    View full details
    Original price $2.89 - Original price $2.89
    Original price
    $2.89
    $2.89 - $2.89
    Current price $2.89
  • Original price $2.89 - Original price $2.89
    Original price
    $2.89
    $2.89 - $2.89
    Current price $2.89

    1 in. Internal Furniture Grade PVC Coupling - Orange

    FORMUFIT 1" Internal Couplings in Orange connect two segments of 1 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden connec...

    View full details
    Original price $2.89 - Original price $2.89
    Original price
    $2.89
    $2.89 - $2.89
    Current price $2.89
  • Original price $2.89 - Original price $2.89
    Original price
    $2.89
    $2.89 - $2.89
    Current price $2.89

    1 in. Internal Furniture Grade PVC Coupling - Yellow

    FORMUFIT 1" Internal Couplings in Yellow connect two segments of 1 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden connec...

    View full details
    Original price $2.89 - Original price $2.89
    Original price
    $2.89
    $2.89 - $2.89
    Current price $2.89
  • Original price $2.89 - Original price $2.89
    Original price
    $2.89
    $2.89 - $2.89
    Current price $2.89

    1 in. Internal Furniture Grade PVC Coupling - Green

    FORMUFIT 1" Internal Couplings in Green connect two segments of 1 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden connect...

    View full details
    Original price $2.89 - Original price $2.89
    Original price
    $2.89
    $2.89 - $2.89
    Current price $2.89
  • Original price $2.89 - Original price $2.89
    Original price
    $2.89
    $2.89 - $2.89
    Current price $2.89

    1 in. Internal Furniture Grade PVC Coupling - Blue

    FORMUFIT 1" Internal Couplings in Blue connect two segments of 1 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden connecti...

    View full details
    Original price $2.89 - Original price $2.89
    Original price
    $2.89
    $2.89 - $2.89
    Current price $2.89
  • Original price $2.89 - Original price $2.89
    Original price
    $2.89
    $2.89 - $2.89
    Current price $2.89

    1 in. Internal Furniture Grade PVC Coupling - Purple

    FORMUFIT 1" Internal Couplings in Purple connect two segments of 1 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden connec...

    View full details
    Original price $2.89 - Original price $2.89
    Original price
    $2.89
    $2.89 - $2.89
    Current price $2.89
  • Original price $2.89 - Original price $2.89
    Original price
    $2.89
    $2.89 - $2.89
    Current price $2.89

    1 in. Internal Furniture Grade PVC Coupling - Pink

    FORMUFIT 1" Internal Couplings in Pink connect two segments of 1 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden connecti...

    View full details
    Original price $2.89 - Original price $2.89
    Original price
    $2.89
    $2.89 - $2.89
    Current price $2.89
  • Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49

    1-1/4 in. Internal Furniture Grade PVC Coupling - White

    FORMUFIT 1-1/4" Internal Couplings in White connect two segments of 1-1/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden...

    View full details
    Original price $2.49 - Original price $2.49
    Original price
    $2.49
    $2.49 - $2.49
    Current price $2.49
  • Original price $2.99 - Original price $2.99
    Original price
    $2.99
    $2.99 - $2.99
    Current price $2.99

    1-1/4 in. Internal Furniture Grade PVC Coupling - Black

    FORMUFIT 1-1/4" Internal Couplings in Black connect two segments of 1-1/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden...

    View full details
    Original price $2.99 - Original price $2.99
    Original price
    $2.99
    $2.99 - $2.99
    Current price $2.99
  • Original price $2.99 - Original price $2.99
    Original price
    $2.99
    $2.99 - $2.99
    Current price $2.99

    1-1/4 in. Internal Furniture Grade PVC Coupling - Gray

    FORMUFIT 1-1/4" Internal Couplings in Gray connect two segments of 1-1/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden ...

    View full details
    Original price $2.99 - Original price $2.99
    Original price
    $2.99
    $2.99 - $2.99
    Current price $2.99
  • Original price $3.49 - Original price $3.49
    Original price
    $3.49
    $3.49 - $3.49
    Current price $3.49

    1-1/4 in. Internal Furniture Grade PVC Coupling - Red

    FORMUFIT 1-1/4" Internal Couplings in Red connect two segments of 1-1/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden c...

    View full details
    Original price $3.49 - Original price $3.49
    Original price
    $3.49
    $3.49 - $3.49
    Current price $3.49
  • Original price $3.49 - Original price $3.49
    Original price
    $3.49
    $3.49 - $3.49
    Current price $3.49

    1-1/4 in. Internal Furniture Grade PVC Coupling - Orange

    FORMUFIT 1-1/4" Internal Couplings in Orange connect two segments of 1-1/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidde...

    View full details
    Original price $3.49 - Original price $3.49
    Original price
    $3.49
    $3.49 - $3.49
    Current price $3.49
  • Original price $3.49 - Original price $3.49
    Original price
    $3.49
    $3.49 - $3.49
    Current price $3.49

    1-1/4 in. Internal Furniture Grade PVC Coupling - Yellow

    FORMUFIT 1-1/4" Internal Couplings in Yellow connect two segments of 1-1/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidde...

    View full details
    Original price $3.49 - Original price $3.49
    Original price
    $3.49
    $3.49 - $3.49
    Current price $3.49
  • Original price $3.49 - Original price $3.49
    Original price
    $3.49
    $3.49 - $3.49
    Current price $3.49

    1-1/4 in. Internal Furniture Grade PVC Coupling - Green

    FORMUFIT 1-1/4" Internal Couplings in Green connect two segments of 1-1/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden...

    View full details
    Original price $3.49 - Original price $3.49
    Original price
    $3.49
    $3.49 - $3.49
    Current price $3.49
  • Original price $3.49 - Original price $3.49
    Original price
    $3.49
    $3.49 - $3.49
    Current price $3.49

    1-1/4 in. Internal Furniture Grade PVC Coupling - Blue

    FORMUFIT 1-1/4" Internal Couplings in Blue connect two segments of 1-1/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden ...

    View full details
    Original price $3.49 - Original price $3.49
    Original price
    $3.49
    $3.49 - $3.49
    Current price $3.49
  • Original price $3.49 - Original price $3.49
    Original price
    $3.49
    $3.49 - $3.49
    Current price $3.49

    1-1/4 in. Internal Furniture Grade PVC Coupling - Purple

    FORMUFIT 1-1/4" Internal Couplings in Purple connect two segments of 1-1/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidde...

    View full details
    Original price $3.49 - Original price $3.49
    Original price
    $3.49
    $3.49 - $3.49
    Current price $3.49
  • Original price $3.49 - Original price $3.49
    Original price
    $3.49
    $3.49 - $3.49
    Current price $3.49

    1-1/4 in. Internal Furniture Grade PVC Coupling - Pink

    FORMUFIT 1-1/4" Internal Couplings in Pink connect two segments of 1-1/4 in. Schedule 40 PVC pipes internally, leaving a smooth, flush, and hidden ...

    View full details
    Original price $3.49 - Original price $3.49
    Original price
    $3.49
    $3.49 - $3.49
    Current price $3.49

Manuals and Downloads

Internal PVC Coupler - Additional Information

◼️Basic Description
Internal couplings adjoin two pieces of Schedule 40 pipe and provide a near seamless appearance when connected. These couplers are extraordinarily useful for larger designs, allowing for more compact storage due to the breakdown points they can provide. Internal Couplers can also extend our shorter pipe lengths to whatever lengths your project requires, with a seamless appearance.

◼️Use
You can use Internal Coupling Furniture Grade PVC fittings to join two pieces of pipe or fittings together. Similar to an external PVC Coupler, these couplings are designed to provide a virtually seamless, invisible, and professional-looking connection between two PVC pipe segments.

Furniture Grade PVC Internal Couplings are designed to construct dependable tight connections with very close tolerances. Given these tight tolerances, the link of pipe and coupling may require subtle hammering to seat and connect the segments entirely and can be difficult to remove once in place. However, you can use them to create breakdown points, quick release junctions, and semi-permanent joints between furniture PVC sections by sanding or filing the inner diameter of the pipe until you reach the desired insertion strength.

The interior of the internal coupling is still pass-through and will allow you to send cabling, wiring, and some fluids through the inner pipe. However, due to the limited internal dimensions, it is not recommended that Internal Couplers be used for fluid passage.

◼️Design
Due to their minimalistic profile, Internal Couplings do not have any markings, labels, barcodes, or embossments and leave a smooth, clean appearance when used with FORMUFIT Furniture Grade PVC. Additionally, they have a glossy, smooth surface finish and leave only a tiny seam when installed for a clean, professional appearance.
Internal couplings can only be used with Schedule 40 PVC pipe and will not work with Schedule 80 or thinwall PVC pipe due to the limitations on the inner diameter.

◼️Engineered Materials
Made in the USA, FORMUFIT Internal PVC Furniture couplers are constructed from high-quality, engineered resins and ultraviolet-resistant compounds. They can be deemed industrial strength as they have nearly 5x the durability against impacts and breakage. In addition, FORMUFIT Couplings offer decades of UV resistance from sunlight damage that typically weakens and discolors off-the-shelf plumbing-grade PVC and low-grade imported copycat products.

FORMUFIT Internal PVC Couplings are manufactured to be fully weatherable and sunlight resistant. They can withstand harsh weather exposure, are non-toxic and safe, and are created without phthalates or heavy metals.

◼️Fitment and Securing
Furniture Grade PVC Internal Couplings are engineered to construct dependable tight connections with very close tolerances. Given these tight tolerances, the link of pipe and coupling may require subtle hammering to seat and connect the segments entirely and can be difficult to remove once in place. However, you can use them to create breakdown points, quick release junctions, and semi-permanent joints between furniture PVC sections by sanding or filing the inner diameter of the pipe until you reach the desired insertion strength. Couplings can be tightly secure via the press-to-fit method, but you can also permanently use PVC cement to weld the connection.