Amps to Volts Calculator

Amps to volts calculator

Amps (A) to volts (V) calculator.

Select calculation type, enter amps and watts or ohms and press the Calculate button to get volts:

Select calculation:

Enter amps: A

Enter watts: W

Result in volts: V

Amps to volts calculation

The voltage V in volts (V) is equal to the power P in watts (W), divided by the current I in amps (A):

V_(V) = P_(W) / I_(A)

The voltage V in volts (V) is equal to the current I in amps (A), times the resistance R in ohms (Ω):

V_(V) = I_(A) × R_(Ω)

Example Calculation

Problem: Calculate the voltage if the current is 5 amps and the power is 100 watts.

Solution:

Using the formula: V = P / I

V = 100W / 5A = 20V

Answer: The voltage is 20 volts.

FAQS

How do you convert milliamps to VA (volt-amperes)?

To convert milliamps to VA, first convert milliamps to amps by dividing by 1000, then multiply by voltage using the formula: VA = (mA ÷ 1000) × V. For example, 500 milliamps at 120V equals 60 VA (0.5A × 120V = 60 VA).

What is the difference between volt-amps and VA in electrical calculations?

Volt-amps and VA are the same measurement – VA is simply the abbreviated form of volt-amperes, representing apparent power in AC circuits. Both terms describe the total power flowing in an electrical circuit, calculated by multiplying voltage times current (V × A = VA).

How do you calculate VA to amps conversion quickly?

To convert VA to amps, divide the VA rating by the voltage: Amps = VA ÷ Voltage. For single-phase: I = VA ÷ V, and for three-phase: I = VA ÷ (√3 × V × 1.732).

What's the formula to convert watts to VA?

Converting watts to VA requires the power factor: VA = Watts ÷ Power Factor. For most residential applications, assume a power factor of 0.8-0.9, so VA = Watts ÷ 0.8 gives a conservative estimate.

How many amps is 1000 VA at different voltages?

At 120V: 1000 VA = 8.33 amps (1000÷120). At 240V: 1000 VA = 4.17 amps (1000÷240). At 208V three-phase: 1000 VA = 2.77 amps (1000÷(208×1.732)).

How do you size a transformer using VA calculations?

Calculate total connected load in VA, add 25% safety margin, then select the next standard transformer size. Sum all equipment VA ratings: motors, lighting, and receptacles, then multiply by 1.25 for proper transformer sizing.

Can you convert 10 amps directly to volts?

You cannot convert amps directly to volts as they measure different electrical properties – current vs. potential difference. You need additional information like resistance (V = I × R) or power (V = P ÷ I) to determine voltage from current.

What is the 3-phase VA calculation formula?

For three-phase VA calculation: VA = √3 × V × I × 1.732, where V is line-to-line voltage and I is line current. For balanced loads, VA = 3 × (phase voltage × phase current).

How do you calculate KVA for electrical equipment sizing?

KVA (kilovolt-amperes) = VA ÷ 1000. Add all equipment VA ratings, include demand factors per NEC guidelines, add 25% spare capacity, then convert to KVA by dividing total VA by 1000.

What's the difference between VA rating and watt rating on UPS systems?

VA rating represents total apparent power capacity, while watt rating shows real power output after accounting for power factor. UPS systems list both because VA determines battery backup time, while watts determine actual load capacity.

How do you calculate VA for motor starting current?

Motor starting VA = Starting Current × Rated Voltage × √3 (for 3-phase). Starting current is typically 6-8 times full load current, so multiply nameplate FLA by starting current multiplier times voltage.

What size breaker do I need for specific VA loads?

Breaker sizing: Amps = VA ÷ Voltage, then select next standard breaker size above calculated current. Add 25% safety margin for continuous loads per NEC 210.20(A) requirements.