How Many Amps Does a Microwave Use? — Quick Answer, Tables & Examples
ZacharyWilliamShort answer first, then the details: amps depend on the microwave’s input watts and your supply voltage. In U.S. kitchens (120V), many countertop units draw about 10–15 A at full power. Jump to the tables or use the mini-calculator below.
Quick Answer
Amps = Input Watts ÷ Volts (ignoring power factor for a simple estimate).
- 120V supply: 1,200W input ≈ 10.0 A • 1,500W ≈ 12.5 A • 1,800W ≈ 15.0 A
- 230V supply: 1,200W input ≈ 5.2 A • 1,500W ≈ 6.5 A • 1,800W ≈ 7.8 A
If you only know the advertised “cooking power” (e.g., 1,000W), the microwave’s input is typically about 1.3–1.6× higher (varies by model). A common rule of thumb is 1.4×.
At-a-Glance: Input Watts → Amps
| Input Watts | Amps @ 120V | Amps @ 230V |
|---|---|---|
| 900 W | 7.5 A | 3.9 A |
| 1,000 W | 8.3 A | 4.3 A |
| 1,100 W | 9.2 A | 4.8 A |
| 1,200 W | 10.0 A | 5.2 A |
| 1,350 W | 11.3 A | 5.9 A |
| 1,500 W | 12.5 A | 6.5 A |
| 1,650 W | 13.8 A | 7.2 A |
| 1,800 W | 15.0 A | 7.8 A |
Numbers rounded to 0.1 A.
Only Know “Cooking Watts”? (Estimate)
| Cooking Watts | Typical Amps | Range @ 120V |
|---|---|---|
| 600 W | 7.0 A | 6.5–8.0 A |
| 700 W | 8.2 A | 7.6–9.3 A |
| 800 W | 9.3 A | 8.7–10.7 A |
| 900 W | 10.5 A | 9.8–12.0 A |
| 1,000 W | 11.7 A | 10.8–13.3 A |
| 1,100 W | 12.8 A | 11.9–14.7 A |
| 1,200 W | 14.0 A | 13.0–16.0 A |
| 1,300 W | 15.2 A | 14.1–17.3 A |
For 230V, divide these amps by ~1.92 (230 ÷ 120) to estimate the typical draw.
Formulas (and Cooking vs Input Watts)
Basic current formula
Amps (A) ≈ Input Watts (W) ÷ Voltage (V)
More precisely: I = P ÷ (V × PF), where PF is power factor (often ~0.9–1 for many modern inverter units). When you don’t know PF, the simple formula above gives a good estimate.
Cooking vs input watts
The “1,000W microwave” on the box is cooking power (microwave output). The electrical input watts on the nameplate are higher (commonly 1.3–1.6×). Always use the input rating when calculating amps.
Microwave Amps — Popular Models (120V)
“Stated” comes from the manufacturer spec when available. “≈calc” is computed as Input Watts ÷ 120 V and rounded to 0.1 A. Values refer to full-power operation; inverter/partial power will draw less.
| Brand & Model | Cooking Watts | Input Watts | Amps @120V Stated |
Amps @120V ≈calc |
|---|---|---|---|---|
| Panasonic NN-SN686S | 1200 | 1480 | — | 12.3 A |
| Toshiba EM131A5C-SS | 1100 | 1550 | — | 12.9 A |
| GE JVM3160RFSS | 1000 | 1580 | 15.0 A | 13.2 A |
| Samsung MS14K6000AS | 1000 | 1600 | 13.3 A | 13.3 A |
| LG LMC2075ST (NeoChef) | 1200 | 1600 | 14.0 A | 13.3 A |
| Sharp SMC1132CS | 1000 | 1500 | — | 12.5 A |
| BLACK+DECKER EM720CB7 | 700 | 1050 | — | 8.8 A |
Microwave Amps — Popular Models (230V/50Hz)
“Stated” comes from the maker’s spec when available. “≈calc” uses Amps ≈ Input Watts ÷ 230 V (rounded to 0.1 A).
| Brand & Model | Cooking Watts | Input Watts | Amps @230V Stated |
Amps @230V ≈calc |
|---|---|---|---|---|
| Samsung MS23K3513AK | 800 | 1150 | — | 5.0 A |
| Panasonic NN-SD27HS | 1100 | 1500 | — | 6.5 A |
| LG MH8265CIS (NeoChef) | 1200 | 1350 | — | 5.9 A |
| Bosch HMT84G654B (built-in) | 900 | 1450 | 10.0 A | 6.3 A |
| Sharp R-28STM | 800 | 1250 | — | 5.4 A |
| Beko MOC20100 | 700 | 1100 | — | 4.8 A |
Notes: Values are for full-power operation. Inverter/partial power will draw less. Always check your unit’s rating label for exact numbers.
Worked Examples
1) Nameplate shows 1,500W input at 120V
I ≈ 1,500 ÷ 120 = 12.5 A
2) You only know it’s a 1,000W microwave (cooking)
Estimate input as ~1.4× → 1,400W. Then I ≈ 1,400 ÷ 120 = 11.7 A. With the 1.3–1.6× range, you’d see roughly 10.8–13.3 A.
3) Energy cost for a 10-minute heat-up
If input is ~1,400W, energy ≈ 1.4 kW × (10/60) h = 0.233 kWh. At $0.15/kWh, that’s about $0.03–$0.04 per use.
What affects current draw?
- Voltage: Lower line voltage → slightly higher amps for the same power.
- Power level & inverter control: Modern inverter units vary input smoothly at partial power; older models cycle on/off.
- Power factor (PF): If PF < 1, actual amps are higher than W ÷ V. When unknown, the simple estimate is fine for sizing.
- Startup inrush: Briefly higher current can occur when switching on.
Breaker & Circuit Notes
- Countertop microwaves (120V): Many operate comfortably on a 15A or 20A branch circuit. If the unit’s nameplate is near 15A (e.g., ~1,800W), a 20A dedicated circuit is commonly recommended by manufacturers.
- Built-in / over-the-range: Often specify a dedicated 15A or 20A circuit—always follow the installation manual.
- Avoid long, thin extension cords: Voltage drop and heat can lead to nuisance trips or cord damage.
- When in doubt: Check the label (usually inside the door frame or on the back) for input watts and current. Those numbers beat estimates.
Safety first: If your breaker trips or the plug/cord feels hot, stop using the appliance and consult a licensed electrician or the manufacturer.
FAQs
Is a 1,000W microwave using 1,000 watts from the wall?
No. That 1,000W is cooking output. Wall (input) power is typically ~1.3–1.6× higher.
Do microwaves need a dedicated circuit?
Many built-in or high-power units do. Countertop models often share a small-appliance circuit but may perform better on a dedicated run. Always follow the manual and local electrical codes.
Why does my microwave dim the lights?
It may be drawing double-digit amps on startup and under load. Shared circuits, voltage drop, or marginal connections can cause lights to dip.
How do I find the exact amps for my model?
Read the nameplate label (inside the door frame, side, or back). It will list input watts and/or current in amps—use those numbers.
