Receptacle Spacing Calculator

The spacing rule and the count formula

Both rules work the same way: a receptacle covers a fixed reach in each direction along the run, so the maximum spacing between two receptacles is twice that reach. The minimum count for a run of length L is L divided by the maximum spacing, rounded up, because a fractional receptacle is another whole receptacle.

Worked example: a 14 ft living-room wall

Take a 14 ft wall between two doorways. Dividing 14 by the 12 ft maximum spacing gives 1.17, which rounds up to 2 receptacles. In practice you would place one within 6 ft of the left doorway and one within 6 ft of the right, no more than 12 ft apart, so that every point on the wall is within 6 ft of a receptacle. A 12 ft wall would need only 1 (a single receptacle at the midpoint reaches both ends), and a 25 ft wall would need 3.

For a kitchen, a 10 ft run of counter divides by the 4 ft countertop maximum spacing to 2.5, rounding up to 3 receptacles, each no more than 24 in from any point on the counter and the first within 2 ft of each end.

Common mistakes

• Measuring only the gap, not the ends. The 6 ft applies to the doorway and corner too, not just the space between receptacles, so the first receptacle cannot be more than 6 ft from where the wall space begins.
• Splitting a corner run. Space measured around a corner is one continuous wall space under 210.52(A)(2). Splitting it at the corner can add a receptacle the code does not require.
• Skipping short walls. Any wall space 2 ft or wider needs a receptacle. Only runs under 2 ft are exempt.
• Confusing the counts. This is a placement rule for receptacles along a run. The number of branch circuits a dwelling needs is a separate calculation under 210.11.

Frequently asked questions

How far apart do receptacles have to be in a dwelling?

NEC 210.52(A) requires that no point along the floor line of any wall space be more than 6 ft from a receptacle. Because a receptacle reaches 6 ft each way, receptacles end up no more than 12 ft apart, with the first within 6 ft of every doorway or corner. This is the 6-foot, 12-foot rule.

What is the 6-foot, 12-foot rule?

The 6 ft is the maximum distance any point on the wall can be from a receptacle; the 12 ft is the resulting maximum spacing between two adjacent receptacles. A wall of length L needs at least L divided by 12, rounded up: a 12 ft wall needs 1, a 14 ft wall needs 2, and a 25 ft wall needs 3.

What counts as a wall space?

Under 210.52(A)(2) a wall space is any space 2 ft or more in width, unbroken along the floor line by doorways, fireplaces, and similar openings. Space around a corner is part of the same wall space. A run under 2 ft wide is not counted. Fixed room dividers and fixed wall panels are also treated as wall space.

How far apart are kitchen countertop receptacles?

NEC 210.52(C)(1) requires a receptacle at each wall countertop 12 in or wider, placed so no point is more than 24 in from a receptacle, a 4 ft maximum spacing with the first within 2 ft of each end. A 4 ft counter needs 1 and a 10 ft counter needs 3. Island and peninsula countertops follow their own rules and are out of scope here.

Does this give the total number of outlets in a room?

No. It gives the minimum general-purpose wall or kitchen countertop receptacles for the runs you enter. The fixed specific-outlet requirements, such as bathroom (210.52(D)), outdoor (210.52(E)), laundry (210.52(F)), and basement or garage (210.52(G)) receptacles, are additional and are placed by location, not by spacing.

Related calculators

• Minimum Branch Circuits Calculator: how many branch circuits the dwelling needs under 210.11, a circuit count rather than a receptacle count.
• Box Fill Calculator: size the device box for each receptacle under NEC 314.16.
• Breaker Size Calculator: size the breaker and conductor for the receptacle circuit.
• Electrical Load Calculator: the dwelling service load once the circuits and outlets are laid out.