Receptacles Per Circuit Calculator
How many receptacles can go on one branch circuit? For a non-dwelling occupancy the tool applies the NEC 220.14(I) 180 VA per strap to the circuit's usable capacity and reports the maximum receptacle count. For a dwelling unit it gives the honest answer - no NEC numeric limit, with 210.52 spacing governing - and a clearly labeled voluntary design guideline.
How to use this calculator
- Pick the occupancy. Non-dwelling (commercial) applies the 220.14(I) 180 VA-per-strap maximum; a dwelling unit has no NEC per-circuit limit.
- Choose the circuit rating (NEC 210.3 standard ratings: 15, 20, 30, 40, 50 A) and the voltage. General-use receptacle circuits are normally 15 or 20 A at 120 V.
- Check continuous load only if the receptacles serve a continuous load; this drops the usable capacity to 80% per NEC 210.20(A).
- Read the maximum receptacle straps (a duplex is one strap) and the usable circuit capacity used to derive it. The notes show the arithmetic and cross-links.
NEC reference
This calculator follows the National Electrical Code (NEC) 2020. Section 220.14(I) counts each single or multiple receptacle on one strap at 180 volt-amperes; Section 210.20(A) sets the continuous-load rule (the overcurrent device must be at least 125% of a continuous load, so a continuous circuit's usable capacity is 80% of its rating); Section 210.3 lists the standard branch-circuit ratings; and Section 210.52 governs dwelling receptacle placement, which is why dwelling units carry no numeric per-circuit receptacle limit. These provisions are unchanged across the 2017, 2020, and 2023 editions, so no edition toggle is offered.
Results are for reference only. Verify against the applicable adopted edition of the NEC and consult a licensed electrician for code compliance.
The formula: 180 VA per strap
In an other-than-dwelling occupancy, NEC 220.14(I) calculates each receptacle at 180 VA per strap (yoke). The number a branch circuit can carry is its usable capacity divided by 180 VA, rounded down:
max receptacles = floor( (circuit amps × volts × [0.8 if continuous]) ÷ 180 )
A duplex receptacle is one strap, so it counts as 180 VA - the same as a single receptacle. A four-plex on two straps is 360 VA and counts as two.
Common results (non-dwelling, 120 V)
| Circuit | Circuit VA | Max receptacles (non-continuous) | Max (continuous, 80%) |
|---|---|---|---|
| 15 A | 1,800 | 10 | 8 |
| 20 A | 2,400 | 13 | 10 |
| 30 A | 3,600 | 20 | 16 |
Counts are 220.14(I) load-calculation figures (180 VA per strap). A 30 A or larger circuit is normally an individual or specific-appliance circuit, not a general-use receptacle circuit. These match the widely published VoltageLab, ExpertCE, and JADE Learning figures.
Dwelling units: no per-circuit limit
The NEC does not limit how many general-use receptacles you may place on a dwelling-unit branch circuit. In a house, receptacle placement is governed by the 210.52 spacing rules (the 6 ft / 12 ft wall rule and the kitchen countertop rule), and the dwelling receptacle load is folded into the 3 VA per square foot general lighting load (Table 220.12), not counted per receptacle. Applying the commercial 180 VA figure to a dwelling circuit - for example, about 13 on a 20-amp circuit - is a voluntary design choice many electricians make, but it is not a Code requirement. Use the Receptacle Spacing Calculator for the placement rules that actually apply in a dwelling.
What this tool does not do
- Fixed multioutlet assemblies (NEC 220.14(H)). Plugmold-type assemblies are 180 VA per 5 ft, or per 1 ft where used simultaneously - a length-based rule, not per strap. See the Multi-Outlet Assembly Load Calculator.
- Conductor and overcurrent-device sizing. Size those with the Wire Size and Breaker Size calculators (NEC 210.19, 240.4, Table 310.16).
- Receptacle spacing and required outlets. The 210.52 placement rules are covered by the Receptacle Spacing Calculator.
- GFCI, AFCI, and tamper-resistant requirements. Those are separate device-protection rules, not a count.
Frequently asked questions
Why 13 and not 12 or 14 on a 20-amp circuit?
A 20-amp, 120-volt circuit is 2,400 VA. Dividing by 180 VA per strap gives 13.33, and the NEC load-calculation figure rounds down to a whole receptacle, so 13 is the maximum. The fourteenth strap would put the calculated receptacle load over the circuit rating in a non-dwelling occupancy.
Do I use 80% for a normal receptacle circuit?
Not usually. General-use receptacles are treated as non-continuous, so the full circuit capacity is used (13 on a 20-amp circuit). Apply the 80% continuous factor (210.20(A)) only when the receptacles serve a load that runs for three hours or more, which lowers a 20-amp circuit to 10 receptacles.
Is this the same as the commercial receptacle load calculation?
No. This tool reports the maximum receptacles a single branch circuit can carry. The Commercial Receptacle Load Calculator goes the other way - it takes a receptacle count and computes the feeder or service load with the Table 220.44 demand factors.
Related calculators
- Commercial Receptacle Load Calculator: the reverse - receptacle count to feeder load with the Table 220.44 demand factors.
- Receptacle Spacing Calculator: the NEC 210.52 dwelling receptacle placement rules (6 ft / 12 ft wall, kitchen countertop).
- Receptacle Rating & Branch-Circuit Load Calculator: which receptacle rating a circuit permits and the maximum cord-and-plug load (Table 210.21(B)).
- Minimum Branch Circuits Calculator: the minimum number of dwelling branch circuits per NEC 210.11.
Studying for the licensing exam? Our own NEC Code Quickstart works all twelve exam calculations start to finish, each with the code reference. Also in paperback. Going for the master license? NEC Master Electrician Exam Practice has 300 master-level questions with fully worked, table-cited answers, built on the 2023 NEC.
Running an electrical contracting business? Jobber handles scheduling, invoicing, and job management. Start a 14-day free trial.
Already have the software and the follow-up still is not happening? That is an unfilled seat rather than a missing tool. Our own Role Build covers the seat: three duties built to run start to finish inside the tools you already pay for.
For deeper NEC training on branch-circuit and receptacle load calculations, Mike Holt's NEC courses are the industry standard.
Working from the printed code? NEC code books and tab sets are available from Mike Holt.
This page contains affiliate links. ElectricalToolbox may earn a commission when you sign up or buy through them, at no additional cost to you.
Get new tools and reference cards by email
Occasional emails when a new calculator, guide, or printable card ships. No spam, unsubscribe anytime.