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Generator Wattage Database
What Is a Generator Wattage Database?
A structured reference of how much power common appliances, tools, and equipment draw — split into running watts (continuous) and starting watts (the surge needed to start motor-driven loads). A generator must deliver both, and this database makes matching easy.
Running
Watts
The continuous power an appliance uses during normal operation. The baseline for sizing your generator.
Starting
Watts (Surge)
The brief 2–3 second spike drawn by motors, often 2–3× the running load. Must be covered by the generator.
Generator
Capacity
The kVA, kW, and amps your genset must provide, matched to your total calculated load.
From Appliance Load to Generator Match
The database lists the running and starting watts of 250+ items. Once you add up your loads, the generator capacity tables let you match your total wattage to a kVA, kW and amp rating — across single or three‑phase, 50 or 60 Hz systems.
Built for Real Loads
More Than a Typical Wattage Chart
01
Searchable & Filterable
Find any appliance instantly — no more hunting through fragmented PDFs or incomplete lists.
02
Global Voltage & Frequency
Covers 50 Hz and 60 Hz systems, with both single‑phase and three‑phase support.
03
Full Data Download
Export the entire database in Excel, CSV, or PDF to keep offline, edit, or share with your team.
04
Generator Output Tables Included
Match your total load directly to a generator's kVA, kW, and amps — all on one page.
Generator Wattage Database
Generator Wattage Database: Running & Starting Watts
Use the search box and category filters to find any appliance or tool. The table below shows representative values for the most common entries; the full database covers 250+ items across Home, RV & Camping, Jobsite & Tools, Industrial & Motors, and Farm.
Appliance & Tool Wattage Reference
Running watts are the continuous power draw. Starting watts are the brief surge required by motors, often 2–3× the running load. Only the largest single starting surge is added to your total running watts — motors rarely all start at once.
| Appliance / Tool | Running Watts | Starting Watts | Notes |
|---|---|---|---|
| Home Appliances | |||
| Refrigerator (18–22 cu ft) | 350–800 | 1,200–2,200 | Surge about 3× running; Energy Star models draw less |
| Freezer (chest) | 300–500 | 1,000–1,500 | Compressor surge |
| Window AC (10,000 BTU) | 1,200–1,500 | 1,800–3,600 | 5,000 BTU models run about 500 W |
| Central AC (3-ton) | 3,000–3,500 | 4,500–10,500 | Largest home load; a hard-start kit cuts surge to ~3× |
| Furnace blower (⅓ HP) | 300–800 | 500–2,350 | Fan motor start |
| Well pump (1 HP) | 1,000–1,500 | 2,000–6,000 | Deep-well pressure cycle |
| Sump pump (½ HP) | 800–1,050 | 1,300–4,100 | Cycles on water level |
| Electric water heater | 3,000–4,500 | 3,000–4,500 | Resistive, no surge |
| Washing machine | 300–1,200 | 600–2,300 | Motor start |
| Electric clothes dryer | 5,000–5,400 | 1,350–6,750 | Resistive plus motor |
| Dishwasher | 1,200–1,500 | 540–3,600 | Motor plus heating |
| Microwave (1,000 W) | 1,000–1,500 | 1,000–1,500 | No significant surge |
| LED lights (whole home) | 100–300 | 100–300 | Minimal draw |
| Jobsite & Industrial Motors | |||
| Circular saw (7¼") | 1,200–1,400 | 2,300–4,800 | Motor inrush |
| Table saw | 1,500–3,000 | 3,000–6,000 | – |
| Miter saw | 1,200–1,800 | 2,400–3,600 | – |
| Air compressor (1 HP) | 1,600 | 2,800–4,500 | Recurring start under load |
| 1 HP motor (generic) | 746 | 2,200–3,300 | 2–3× surge typical |
| 5 HP motor (industrial) | ~3,700 | 11,000–15,000 | Direct-on-line start |
| 20 HP motor (industrial) | ~14,900 | 45,000+ | Needs soft-start planning |
| Welder (150 A) | 5,000–10,000 | 10,000+ | Size on continuous duty |
| Commercial fridge | 800–1,500 | 2,400–4,500 | – |
Values are planning ranges, verified 2026-08.
Always confirm from the appliance nameplate; most plates list amps, so multiply volts × amps to get watts. The interactive database sorts, filters, and converts to kW, and the full 250+ row dataset is available as a download.
Surge math: Only the single largest starting surge is added to your total running watts, because motors rarely all start at the same instant. Add them all and you'll oversize the generator and pay for capacity you never use.
Generator Output Capacity: kVA, kW & Amps
Generator output is rated in kVA (total capacity) and kW (usable power), connected by the power factor, typically 0.8 for industrial three-phase. Amps per phase follow from the standard formulas: Three‑phase: amps = kVA × 1000 ÷ (1.732 × voltage). Single‑phase: amps = kW × 1000 ÷ (voltage × power factor).
| Generator Size (kVA) | kW (0.8 PF) | Amps @ 230 V 3‑ph | Amps @ 400 V 3‑ph | Amps @ 120/240 V 1‑ph |
|---|---|---|---|---|
| 8 kVA | 6.4 kW | 20 A | 12 A | – |
| 15 kVA | 12 kW | 38 A | 22 A | – |
| 25 kVA | 20 kW | 63 A | 36 A | – |
| 40 kVA | 32 kW | 100 A | 58 A | – |
| 62.5 kVA | 50 kW | 157 A | 90 A | – |
| 100 kVA | 80 kW | 251 A | 144 A | – |
| 160 kVA | 128 kW | 402 A | 231 A | – |
| 250 kVA | 200 kW | 628 A | 361 A | – |
| 320 kVA | 256 kW | 803 A | 462 A | – |
| 500 kVA | 400 kW | 1,255 A | 722 A | – |
| 1,000 kVA | 800 kW | – | 1,443 A | – |
| 2,000 kVA | 1,600 kW | – | 2,887 A | – |
| 4,000 kVA | 3,200 kW | – | 5,774 A | – |
Planning values at 0.8 power factor, 50 Hz.
Single‑phase sets cover the smaller range for residential backup. Use our kW to amps calculator for exact conversions at your voltage and phase.
To match load to capacity: Add up your running watts from the database, divide by 1,000 to get kW, and divide again by 0.8 to get the kVA you need. A home essentials load of 4 kW needs roughly a 5 kVA single‑phase set; an 80 kW warehouse load needs about 100 kVA, and with a safety factor, closer to 125 kVA.
Wattage Rules
How Generator Wattage Works
The database is only as good as the rules you apply to it. Here are the four that matter most: running vs. starting watts, converting nameplate amps, the sizing formula, and altitude/heat derating. Apply them correctly and you get a generator size that actually works.
01
Running Watts vs. Starting Watts
Running watts are the steady draw; starting watts are the spike. The generator must handle the spike. A refrigerator draws 350–800 W running but surges to 1,200–2,200 W every time the compressor cycles on. Size for the surge.
02
Nameplates List Amps, Not Watts
Most appliances print amps on the data plate. Convert with watts = volts × amps. A refrigerator on a 120 V circuit drawing 5 A uses 600 W. This one conversion trips up more DIY sizing than any other step.
03
The Sizing Formula
Total watts needed = sum of all running watts + the single highest starting‑watt surge, then add a 20–25% safety margin. The margin covers voltage dips, future additions, and the fact that no generator should run pinned at 100% load.
04
Altitude and Heat Cost You Output
Generator output drops roughly 3% per 1,000 ft of elevation above about 3,000 ft and falls in extreme heat. A set sized at sea level can come up short at altitude, so a derating adjustment belongs in any serious calculation.
The generator wattage database values are planning estimates, not guarantees. Every row is dated and sourced. The generator wattage calculator applies these rules automatically: pick your appliances from the same database and it totals your running watts, layers in the surge, applies the margin, and returns your recommended size.
Worked Examples
What Size Generator Do I Need? Use the Database
The fastest way to a defensible number is to build your load list from the database and total it. Three worked examples show the method.
Example 1 – Home Essentials
Outage backup: Refrigerator (700 W running / 2,200 W start), furnace blower (600 W / 1,600 W), sump pump (1,000 W / 4,100 W), LED lights (200 W), TV and router (200 W). Running total ≈ 2,700 W; peak = 2,700 + (4,100 − 1,000) = 5,800 W; with 20% margin, a 7,000 W generator.
Example 2 – Whole-Home Comfort
Add a window AC (1,500 W running / 3,600 W start), microwave (1,200 W), and electric water heater (4,000 W). Running total ≈ 9,400 W; peak ≈ 9,400 + (3,600 − 1,500) = 11,500 W; with margin, a 13–15 kW class.
Example 3 – Jobsite
A 1 HP air compressor (1,600 W / 4,500 W), two circular saws (1,400 W each running, one surging at a time), site lighting (1,000 W), and a microwave (1,000 W). Running total ≈ 5,400 W; peak ≈ 5,400 + (4,500 − 1,600) = 8,300 W; with margin, a 10 kW class — roughly a 12.5 kVA diesel set.
Industrial Sizing
What Size Diesel Generator for a Warehouse or Construction Site?
If you're reading this from a project office rather than a living room, the unit of measure changes from watts to kVA, and the appliance list becomes a connected load. The database's industrial motor rows give you the running and starting watts for pumps, compressors, saws, and welders; the capacity table converts the total to kVA.
| Application | Typical Range | Notes |
|---|---|---|
| Small residential construction site | 20–40 kVA | Tools, lighting, site office |
| Medium commercial construction site | 80–200 kVA | Mixers, compressors, pumps |
| Large civil / infrastructure project | 200–500 kVA | Multiple pumps, heavy equipment |
| Warehouse | 100–400 kVA | HVAC, conveyors, dock equipment |
| Factory / manufacturing | 100–2,000 kVA | Production lines, CNC, compressors |
| Data center | 500–4,000 kVA | N+1 redundancy, UPS, cooling |
Apply a demand factor of 0.7–0.8 on a busy site, since not every piece of equipment runs at full load simultaneously, and size so the largest motor's starting kVA stays under roughly 60–65% of the generator's rated kVA.
Critical Diesel Rules
The Diesel‑Specific Rules That Surprise Most Buyers
Diesel generators prefer to run in the 70–80% load sweet spot. Below about 30% load they wet‑stack: carbon builds up, fuel efficiency drops, and wear accelerates. Oversizing "to be safe" is expensive, not safe.
01
Wet‑Stacking from Low Load
Running a diesel generator below 30% load for extended periods causes incomplete combustion, carbon buildup in the exhaust, and accelerated engine wear. Size for the load, not for "just in case."
02
Oversizing Is Expensive, Not Safe
A generator that's too large costs more upfront, burns more fuel at low efficiency, and suffers increased maintenance. The sweet spot is 70–80% of rated capacity for prime power, 60–75% for standby.
03
Motor Starting kVA Limits
The largest motor's starting kVA should stay under roughly 60–65% of the generator's rated kVA. If it exceeds that, the voltage dip can stall the motor and trip the generator breaker.
04
Demand Factor on Job Sites
On a busy site, 0.7–0.8 demand factor is realistic — not every tool runs at full load simultaneously. Calculate connected load first, then apply the factor before sizing the set.
05
Altitude and Heat Are Real
A generator sized at sea level loses roughly 3% per 1,000 ft above 3,000 ft. Hot weather adds another derating layer. Always apply environmental correction before final selection.
The generator wattage database values are planning estimates, not guarantees. Final size should always be confirmed against the complete load schedule, motor‑starting sequence, power factor, site conditions, and duty rating before equipment is ordered.
Let's talk
Find Every Appliance Running & Starting Wattage
Search 250+ appliances, tools, and industrial motors. Get running watts, starting surge, and kW equivalent — then download the full spreadsheet or use the generator wattage calculator to size your genset in seconds.
Frequently Ask Questions
Q: How many watts does a refrigerator use?
A: About 350–800 W running and 1,200–2,200 W starting. The surge matters for sizing because the compressor draws it every time the fridge cycles on, so size the generator for the starting figure.
Q: How many watts does a window AC use?
A: A 10,000 BTU window unit runs at about 1,200–1,500 W but needs roughly 1,800–3,600 W to start. Powering a window AC from a generator means sizing for the surge.
Q: How many watts does a well pump use?
A: A 1 HP well pump runs at about 1,000–1,500 W and starts at 2,000–6,000 W. Well pumps are among the biggest surges in a home because the motor starts under load against pressure.
Q: How many watts does a sump pump use?
A: A ½ HP sump pump runs at about 800–1,050 W and starts at 1,300–4,100 W. It cycles frequently during wet weather, so the running total matters as much as the surge.
Q: What's the difference between running watts and starting watts?
A: Running watts are the continuous draw while an appliance operates; starting watts are the brief spike a motor pulls for its first seconds, often 2–3 times running. Your generator must deliver the starting watts or the motor won’t start.
Q: How do I calculate total wattage for a generator?
A: Add the running watts of everything you’ll run at once, add the single largest starting surge, then apply a 20–25% safety margin. The result is the generator size you need in watts.
Q: What can a 5,000-watt generator run?
A: A 5,000 W generator runs the home essentials: refrigerator, furnace blower, sump pump, well pump, lights, TV, and a microwave, with one large motor at a time. It won’t run central AC or an electric water heater.
Q: How many amps does a 100 kVA generator produce?
A: A 100 kVA generator at 400 V three-phase, 0.8 power factor, produces about 144 A per phase. At 230 V three-phase it’s about 251 A. Use the capacity table above for other sizes.