Wire Gauge Calculator

Determine the proper wire gauge for a circuit based on amperage, run distance, and voltage. Compare wire sizes by ampacity, voltage drop, and cost to find the most economical option that meets NEC requirements.

Wire Type

Voltage

Circuit Parameters

Circuit Amperage (A)

Wire Run Distance (ft)

Max Voltage Drop (%)

Pricing per Foot (edit to match local rates)

14 AWG ($/ft)

12 AWG ($/ft)

10 AWG ($/ft)

8 AWG ($/ft)

6 AWG ($/ft)

4 AWG ($/ft)

2 AWG ($/ft)

1/0 AWG ($/ft)

Recommended Gauge

8 AWG

40A capacity

Voltage Drop

1.95%

Max allowed: 3%

Wire Cost

$97.50

75 ft of 8 AWG

Purchase Option	Quantity	Est. Cost
14 AWG (15A)	7.85% drop - FAILS	$26.25
12 AWG (20A)	4.95% drop - FAILS	$37.50
10 AWG (30A)	3.1% drop - FAILS	$63.75
8 AWG (40A)Best value	1.95% drop	$97.50
6 AWG (55A)	1.23% drop	$142.50
4 AWG (70A)	0.77% drop	$210.00
2 AWG (95A)	0.48% drop	$315.00
1/0 AWG (125A)	0.31% drop	$487.50

Recommended: 8 AWG copper ($97.50)8 AWG is the smallest (most economical) wire gauge that meets both the 20A ampacity requirement and keeps voltage drop at 1.95% (under your 3% limit) over 75 ft.

This calculator provides estimates based on NEC ampacity tables and standard voltage drop formulas. Actual installations must comply with local electrical codes. Always consult a licensed electrician for final wire sizing decisions.