A = VA ÷ V · Example: 500 VA ÷ 120 V = 4.17 A
📊 Quick Reference Table (single-phase)
| VA | A @120 V | A @220 V | A @240 V |
|---|---|---|---|
| 100 | 0.83 | 0.45 | 0.42 |
| 200 | 1.67 | 0.91 | 0.83 |
| 300 | 2.50 | 1.36 | 1.25 |
| 500 | 4.17 | 2.27 | 2.08 |
| 1000 | 8.33 | 4.55 | 4.17 |
| 2000 | 16.67 | 9.09 | 8.33 |
❓ Quick FAQ
How many amps is 500 VA at 120 V?
4.17 A. Formula: 500 ÷ 120 = 4.17 A.
Do I need power factor?
No — VA already includes PF. The formula A = VA ÷ V gives you total current regardless of PF.
A VA to amps calculator answers one of the most common questions when working with UPS units, transformers, and stabilizers: “how much current does this equipment draw?” The VA rating on the nameplate tells you the apparent power, but breakers and wiring are sized in amps. To bridge the gap, divide VA by voltage. This page gives you an instant calculator for single-phase and three-phase systems, the complete formula, a conversion table for every standard VA rating from 100 to 10,000, and six real-world examples you can apply directly to your installation.
VA to Amps Conversion Table — Standard Equipment Ratings
The table below converts the most common VA ratings found on UPS units, transformers, stabilizers, and inverters to amps at standard voltages. For single-phase: A = VA ÷ V. For three-phase: A = VA ÷ (V × √3). All single-phase values below.
| VA | A @ 120 V | A @ 220 V | A @ 230 V | A @ 240 V | Typical Equipment |
|---|---|---|---|---|---|
| 100 | 0.83 | 0.45 | 0.43 | 0.42 | Small control transformer |
| 150 | 1.25 | 0.68 | 0.65 | 0.63 | Doorbell / thermostat transformer |
| 200 | 1.67 | 0.91 | 0.87 | 0.83 | Control circuit transformer |
| 300 | 2.50 | 1.36 | 1.30 | 1.25 | Small desktop UPS |
| 500 | 4.17 | 2.27 | 2.17 | 2.08 | Home UPS (PC + monitor) |
| 650 | 5.42 | 2.95 | 2.83 | 2.71 | Entry desktop UPS |
| 800 | 6.67 | 3.64 | 3.48 | 3.33 | Home office UPS |
| 1,000 | 8.33 | 4.55 | 4.35 | 4.17 | Single-server UPS / stabilizer |
| 1,500 | 12.50 | 6.82 | 6.52 | 6.25 | Rack-mount server UPS |
| 2,000 | 16.67 | 9.09 | 8.70 | 8.33 | Dual-server UPS |
| 2,200 | 18.33 | 10.00 | 9.57 | 9.17 | Portable generator (EU) |
| 3,000 | 25.00 | 13.64 | 13.04 | 12.50 | Small server rack UPS |
| 5,000 | 41.67 | 22.73 | 21.74 | 20.83 | Medium online UPS |
| 10,000 | 83.33 | 45.45 | 43.48 | 41.67 | Large rack / data center UPS |
How to Convert VA to Amps — Formula Step by Step
VA (volt-amperes) is the product of voltage and current: VA = V × A. To find the current, simply reverse the multiplication — divide VA by voltage. The formula differs slightly for three-phase because the effective voltage includes the √3 factor.
Single-Phase
A 500 VA UPS on a 120 V outlet draws 500 ÷ 120 = 4.17 A. That is the total line current including both the real (watts) and reactive components. You don’t need to know the power factor — VA already includes it.
Three-Phase
For three-phase, V is the line-to-line voltage. A 10,000 VA three-phase transformer at 480 V draws 10,000 ÷ (480 × 1.732) = 10,000 ÷ 831.4 = 12.03 A per line. The √3 factor (≈ 1.732) accounts for the geometric relationship between line and phase voltages in a three-phase system. This relationship is standardized by IEEE and defined in IEC 60038.
Why no power factor in this formula?
Because VA is apparent power — it already equals V × A by definition. When you divide VA by V, the voltage cancels out and you get A directly. Power factor only appears when you convert watts (real power) to amps. If someone gives you a watt rating instead of VA, use A = W ÷ (V × PF). But when the nameplate says “500 VA,” the formula is simply 500 ÷ V.
VA vs Amps — Understanding the Units
VA and amps are related but measure different things. Here is a side-by-side comparison:
| Characteristic | VA (Volt-Ampere) | Ampere (A) |
|---|---|---|
| What it measures | Apparent power (V × A product) | Electric current (electron flow rate) |
| Depends on voltage? | Yes — VA = V × A | No — amps is independent |
| Where you see it | UPS ratings, transformer nameplates | Breakers, fuses, wire ratings |
| Includes reactive power? | Yes — VA = total current × voltage | Yes — amps includes reactive current |
| Used to size | Transformers, UPS, generators | Wires, breakers, fuses, connectors |
| SI unit? | Not a base unit (derived: V × A) | Yes — one of 7 SI base units |
The key practical takeaway: a “500 VA” UPS on a 120 V circuit draws 4.17 A, but the same UPS on a 220 V circuit draws only 2.27 A. The VA rating stays the same — the amps change with voltage. This is why you always need to know the voltage before you can determine the breaker or wire size required.
Amps to VA — Inverse Conversion
To reverse the conversion, multiply instead of dividing:
| Amps | VA @ 120 V | VA @ 220 V | VA @ 240 V |
|---|---|---|---|
| 1 | 120 | 220 | 240 |
| 2 | 240 | 440 | 480 |
| 5 | 600 | 1,100 | 1,200 |
| 10 | 1,200 | 2,200 | 2,400 |
| 15 | 1,800 | 3,300 | 3,600 |
| 20 | 2,400 | 4,400 | 4,800 |
| 30 | 3,600 | 6,600 | 7,200 |
| 50 | 6,000 | 11,000 | 12,000 |
For the full inverse tool, check our Amperes to VA Calculator which converts directly from current and voltage to VA.
Solved Examples — 6 Real-World Cases
Example 1 — 100 VA Control Transformer (120 V)
Data: Control transformer rated 100 VA, secondary voltage 120 V.
Formula: A = 100 ÷ 120 = 0.83 A
A 100 VA control transformer supplies less than 1 amp — enough for pilot lights, control relays, and door chimes. A 1 A fuse on the secondary is standard protection.
Example 2 — 300 VA Desktop UPS (120 V)
Data: Small desktop UPS rated 300 VA, 120 V input.
Formula: A = 300 ÷ 120 = 2.50 A
A 300 VA UPS draws only 2.50 A — comfortably fits on any 15 A or 20 A branch circuit alongside other office equipment. It protects a single monitor and router for about 5 minutes.
Example 3 — 500 VA Home UPS (220 V)
Data: Home UPS rated 500 VA, 220 V supply (India / EU).
Formula: A = 500 ÷ 220 = 2.27 A
At 220 V, a 500 VA UPS draws barely over 2 A. This is why even a 6 A MCB (common in Indian residential wiring) has plenty of capacity for the UPS plus other light loads on the same circuit.
Example 4 — 200 VA Transformer (240 V)
Data: A 200 VA isolation transformer, primary 240 V.
Formula: A = 200 ÷ 240 = 0.83 A
Under 1 amp on the primary side. This type of transformer is used in industrial control panels to provide an isolated 120 V supply for instrumentation and HMI screens.
Example 5 — 2000 VA Server UPS (120 V)
Data: Rack-mount UPS rated 2,000 VA, 120 V input.
Formula: A = 2000 ÷ 120 = 16.67 A
At 16.67 A, this UPS requires a dedicated 20 A circuit (NEC 80% continuous rule: 20 × 0.80 = 16 A is technically exceeded, so a 30 A circuit is safest for continuous operation). Many data centers use 208 V or 240 V inputs to reduce the current draw.
Example 6 — 5000 VA Three-Phase Transformer (480 V)
Data: A 5,000 VA (5 kVA) three-phase dry-type transformer, 480 V primary.
Formula: A = 5000 ÷ (480 × 1.732) = 5000 ÷ 831.4 = 6.01 A
A 5 kVA three-phase transformer draws only 6 A per line at 480 V. A 15 A breaker with 14 AWG wire is more than adequate for the primary protection — per NEC 450.3(B) the primary OCPD can be up to 125% of rated current.
Practical Applications — When and Where You Need VA to Amps
Converting VA to amps comes up in four common scenarios:
UPS circuit sizing
Every UPS nameplate shows a VA rating, but the breaker and wiring must be sized in amps. A 1,500 VA UPS on 120 V draws 12.50 A — that fits on a 15 A circuit for non-continuous use, but needs a 20 A circuit if it runs continuously (80% rule). On 220 V the same UPS draws only 6.82 A, fitting easily on any standard circuit. Always convert VA to amps before selecting the branch circuit.
Transformer primary protection
NEC Article 450 sizes transformer overcurrent protection based on primary amps, not VA. To calculate the fuse or breaker size, first convert the VA rating to amps: A = VA ÷ V. A 500 VA, 120 V transformer draws 4.17 A. Per NEC 450.3(B), the primary OCPD can be up to 125% of rated current: 4.17 × 1.25 = 5.21 A, so a 5 or 6 A fuse is appropriate.
Generator load calculation
When adding loads to a generator load schedule, each device’s VA rating must be converted to amps at the generator’s output voltage. The total amps on each phase determines the generator’s circuit breaker sizing and conductor routing.
Stabilizer and inverter selection
Voltage stabilizers and power inverters are rated in VA. To know if your existing wiring can handle the device, convert VA to amps and compare against the circuit breaker rating. A 2,200 VA stabilizer on 220 V draws 10 A — a 16 A MCB handles it with margin.
Quick Equivalences — VA to Amps
Direct answers for the most searched VA-to-amps conversions. All values are single-phase unless noted. The formula is always A = VA ÷ V.
100 VA to Amps
0.83 A at 120 V · 0.45 A at 220 V
Small control transformer or doorbell transformer. Under 1 A at any standard voltage.
150 VA to Amps
1.25 A at 120 V · 0.68 A at 220 V
Thermostat transformer or small isolation transformer for control circuits.
200 VA to Amps
1.67 A at 120 V · 0.91 A at 220 V
Control-circuit transformer in industrial panels. Easily protected by a 2 A fuse.
300 VA to Amps
2.50 A at 120 V · 1.36 A at 220 V
Small desktop UPS for a monitor and router. Fits any standard outlet.
500 VA to Amps
4.17 A at 120 V · 2.27 A at 220 V
Standard home UPS for a PC and monitor. Most popular consumer UPS size worldwide.
1000 VA to Amps
8.33 A at 120 V · 4.55 A at 220 V
Home office or single-server UPS. Also a common stabilizer size for refrigerators.
1500 VA to Amps
12.50 A at 120 V · 6.82 A at 220 V
Rack-mount server UPS. At 120 V needs a dedicated 20 A circuit for continuous u
se.2000 VA to Amps
16.67 A at 120 V · 9.09 A at 220 V
Dual-server UPS. At 120 V this exceeds the NEC 80% rule for a 20 A circuit — consider 208 V or 240 V input.
3000 VA to Amps
25.00 A at 120 V · 13.64 A at 220 V
Small server rack UPS. At 120 V requires a 30 A dedicated circuit.
5000 VA to Amps
41.67 A at 120 V · 22.73 A at 220 V
Medium online UPS. Almost always connected at 208 V or 240 V to keep current manageable (20.83 A at 240 V).
Frequently Asked Questions
How do you convert VA to amps?
Divide VA by voltage: A = VA ÷ V. For three-phase, divide by V × √3: A = VA ÷ (V × 1.732). No power factor is needed because VA already represents apparent power (V × A).
How many amps is 100 VA at 120 V?
0.83 amps. Calculation: 100 ÷ 120 = 0.83 A. At 220 V it drops to 0.45 A. This is a typical small control transformer drawing under 1 amp.
How many amps is 300 VA?
2.50 amps at 120 V, or 1.36 amps at 220 V. Formula: 300 ÷ 120 = 2.50 A. A small desktop UPS at this rating fits on any standard residential circuit.
How many amps is 500 VA at 220 V?
2.27 amps. Calculation: 500 ÷ 220 = 2.27 A. At 120 V it would be 4.17 A. A 500 VA UPS is the most popular home UPS size worldwide.
How many amps is 200 VA?
1.67 amps at 120 V, or 0.91 amps at 220 V. A 200 VA transformer is common in industrial control panels for powering HMI screens, PLCs, and indicator lights.
How many amps is 2000 VA at 220 V?
9.09 amps. Calculation: 2,000 ÷ 220 = 9.09 A. At 120 V it would be 16.67 A — exceeding the 80% continuous load limit on a 20 A circuit. Higher voltage reduces the current significantly.
Do I need power factor to convert VA to amps?
No. VA = V × A by definition, so A = VA ÷ V with no power factor involved. Power factor only appears when converting watts to amps. If the nameplate shows VA (not watts), just divide by voltage.
How many amps is 1000 VA at 120 V?
8.33 amps. Calculation: 1,000 ÷ 120 = 8.33 A. A 1 kVA UPS at 120 V fits on a 15 A circuit with headroom for other small loads.
What is the difference between VA and amps?
VA measures apparent power — the product of voltage and current. Amps measures only the current. They are related by voltage: VA = V × A. A 500 VA device draws 4.17 A at 120 V but only 2.27 A at 220 V — same VA, different amps because the voltage changed.
How do I convert VA to amps for three-phase?
Use A = VA ÷ (V × √3). Example: 5,000 VA at 480 V three-phase = 5,000 ÷ (480 × 1.732) = 6.01 A per line. The √3 factor accounts for the three-phase voltage geometry.
How many amps is 35 amperes in VA?
This question is reversed — 35 amps is a current, not a VA rating. To find VA from amps: VA = V × A. At 220 V: 220 × 35 = 7,700 VA (7.7 kVA). At 120 V: 120 × 35 = 4,200 VA.
How many amps does a 5000 VA UPS draw?
20.83 amps at 240 V, 22.73 amps at 220 V, or 41.67 amps at 120 V. At 120 V this requires a 50 A circuit — which is why most 5 kVA UPS units use 208 V or 240 V input to keep current under 25 A.
Related Conversions
Explore more electrical conversion calculators on our site:
- Amperes to VA Calculator — the inverse conversion from amps and voltage to VA.
- Amp to kW Calculator — convert amperes to kilowatts.
- Amps to Watts Calculator — convert current to watts with formula and table.
- UPS Size Calculator (kVA/kW) — find the exact UPS size for IT/servers.
- Transformer kVA Sizing Calculator — size transformers from demand load.