Quick Answer: A 100 kVA single-phase dry-type transformer weighs approximately 400 lbs (181 kg).
The same rating in three-phase dry-type weighs about 650 lbs (295 kg), in oil-filled about 850 lbs (386 kg), and a
padmount version about 750 lbs (340 kg). Use our complete weight charts below covering 5 kVA to 2,500 kVA across all
three transformer types—dry-type, oil-filled, and padmount.
Planning a transformer installation? The first question isn’t always about voltage or capacity—it’s about weight. I
learned this the hard way early in my career when a contractor ordered a 500 kVA three-phase unit without checking
the floor load capacity of an aging industrial building. The transformer arrived weighing over 1,200 lbs—and the
second-floor installation location couldn’t support it. That $15,000 mistake could have been avoided with a simple
weight reference.
After 10+ years of manufacturing and shipping transformers at Transformer4U,
I’ve compiled the most complete transformer weight reference available online. Whether you’re specifying rigging
equipment, checking floor ratings, or estimating freight costs, these charts have you covered.
dry-type, oil-filled, and padmount units from 5 to 2,500 kVA.
Why Transformer Weight Matters
Before diving into the charts, here’s why weight data is critical for your project:
| Planning Area | Why Weight Matters | Consequence of Ignoring |
|---|---|---|
| Structural loading | Floor/roof must support static weight | Structural failure, code violation |
| Rigging & crane selection | Crane capacity must exceed transformer weight | Dropping, equipment damage |
| Foundation design | Pad dimensions depend on weight distribution | Settling, oil containment failure |
| Freight & shipping | Weight determines shipping class and cost | Budget overruns by 20-40% |
| Installation access | Doorways, elevators, corridors have load limits | Costly rerouting or wall removal |
| Seismic requirements | Anchoring calculations use weight as input | Non-compliant installation per IEEE 693 |
Dry-Type Transformer Weight Chart
Dry-type transformers are the lightest option per kVA, making them popular for indoor installations where structural limitations exist.
Single-Phase Dry-Type Transformer Weight
| kVA Rating | Weight (lbs) | Weight (kg) | Typical Application |
|---|---|---|---|
| 5 | 80 | 36 | HVAC controls, small panels |
| 7.5 | 100 | 45 | Lighting circuits |
| 10 | 120 | 54 | Small commercial loads |
| 15 | 170 | 77 | Office equipment |
| 25 | 190 | 86 | Medium commercial loads |
| 37.5 | 285 | 129 | Industrial panels |
| 50 | 280 | 127 | Motor control centers |
| 75 | 350 | 159 | Large commercial loads |
| 100 | 400 | 181 | Industrial facilities |
| 167 | 500 | 227 | Large industrial loads |
| 250 | 650 | 295 | Heavy industrial |
Data based on typical 480V primary / 120/240V secondary configurations. Weights are approximate and vary ±10% by manufacturer.
For detailed single-phase specifications including dimensions, full load amps, and wiring guidance, see our
individual kVA guides:
- 5 kVA Single-Phase Transformer Specifications
- 25 kVA Single-Phase Transformer Specifications
- 50 kVA Single-Phase Transformer Specifications
- 100 kVA Single-Phase Transformer Specifications
Three-Phase Dry-Type Transformer Weight
| kVA Rating | Weight (lbs) | Weight (kg) | Typical Application |
|---|---|---|---|
| 15 | 190 | 86 | Small commercial |
| 30 | 285 | 129 | Office buildings |
| 45 | 360 | 163 | Medium commercial |
| 75 | 500 | 227 | Industrial facilities |
| 112.5 | 650 | 295 | Manufacturing plants |
| 150 | 800 | 363 | Large commercial |
| 225 | 860 | 390 | Industrial complexes |
| 300 | 1,050 | 476 | Data centers |
| 500 | 1,200 | 544 | Large factories |
| 750 | 1,300 | 590 | Utility substations |
| 1,000 | 1,900 | 862 | Major industrial |
| 1,500 | 2,500 | 1,134 | Power plants |
| 2,000 | 3,200 | 1,451 | Heavy industry |
| 2,500 | 4,500 | 2,041 | Utility-scale |
For detailed three-phase specifications, visit our complete guides:
- 75 kVA Three-Phase Transformer
- 150 kVA Three-Phase Transformer
- 500 kVA Three-Phase Transformer
- 1000 kVA Three-Phase Transformer
- 2500 kVA Three-Phase Transformer
🔧 Factory Insight: In our production facility, we weigh every transformer before shipment.
Three-phase units above 500 kVA consistently weigh 5-8% more than catalog values suggest—the difference comes from
additional bus bars, hardware, and thicker gauge wiring that manufacturers add for thermal margins. Always request
the actual shipping weight from your manufacturer, not just catalog data.
Oil-Filled Transformer Weight Chart
Oil-filled transformers are significantly heavier than dry-type units due to the insulating oil and steel tank. Plan
for approximately 1.5× the dry-type weight for the same kVA rating.
Three-Phase Oil-Filled Transformer Weight
| kVA Rating | Total Weight (lbs) | Total Weight (kg) | Oil Weight (lbs) | Oil Weight (kg) |
|---|---|---|---|---|
| 10 | 200 | 91 | ~40 | ~18 |
| 15 | 250 | 113 | ~50 | ~23 |
| 25 | 350 | 159 | ~70 | ~32 |
| 37.5 | 450 | 204 | ~90 | ~41 |
| 50 | 550 | 249 | ~110 | ~50 |
| 75 | 700 | 318 | ~145 | ~66 |
| 100 | 850 | 386 | ~175 | ~79 |
| 112.5 | 950 | 431 | ~195 | ~88 |
| 150 | 1,150 | 522 | ~240 | ~109 |
| 225 | 1,400 | 635 | ~300 | ~136 |
| 300 | 1,700 | 771 | ~370 | ~168 |
| 500 | 2,200 | 998 | ~500 | ~227 |
| 750 | 3,000 | 1,361 | ~700 | ~318 |
| 1,000 | 4,000 | 1,814 | ~950 | ~431 |
| 1,500 | 5,500 | 2,495 | ~1,350 | ~612 |
| 2,000 | 7,200 | 3,266 | ~1,800 | ~816 |
| 2,500 | 9,000 | 4,082 | ~2,250 | ~1,021 |
Oil weight is approximate—actual volume varies by manufacturer design. For precise oil quantities, see our Transformer Oil Capacity Chart.
For detailed oil-filled specifications:
- 75 kVA Oil-Filled Transformer
- 500 kVA Oil-Filled Transformer
- 1000 kVA Oil-Filled Transformer
- 2500 kVA Oil-Filled Transformer
⚠️ Critical Note: Oil-filled transformer weight has two important values: total
weight (for foundation design) and liftable weight (total minus oil, for crane selection). Many
installations drain oil before lifting, then refill on-site. Always check if your weight spec includes oil.
Padmount Transformer Weight Chart
Padmount transformers include a weatherproof steel enclosure, making them the heaviest per kVA. They’re designed for outdoor installation on a concrete pad.
Padmount Transformer Weight
| kVA Rating | Weight (lbs) | Weight (kg) | Min. Pad Size (ft) |
|---|---|---|---|
| 25 | 200 | 91 | 4′ × 4′ |
| 37.5 | 400 | 182 | 4′ × 4′ |
| 50 | 500 | 227 | 5′ × 5′ |
| 75 | 640 | 290 | 5′ × 5′ |
| 100 | 750 | 340 | 5′ × 6′ |
| 112.5 | 800 | 363 | 5′ × 6′ |
| 150 | 950 | 432 | 6′ × 6′ |
| 225 | 950 | 432 | 6′ × 7′ |
| 300 | 1,200 | 544 | 6′ × 8′ |
| 500 | 1,250 | 567 | 7′ × 8′ |
| 750 | 1,500 | 680 | 7′ × 9′ |
| 1,000 | 1,600 | 726 | 8′ × 10′ |
| 1,500 | 1,900 | 862 | 8′ × 10′ |
| 2,000 | 2,000 | 908 | 9′ × 11′ |
| 2,500 | 2,400 | 1,090 | 10′ × 12′ |
For detailed padmount specifications:
- 75 kVA Padmount Transformer
- 500 kVA Padmount Transformer
- 1000 kVA Padmount Transformer
- Padmount Transformer Sizing Chart
Weight Comparison: Dry-Type vs Oil-Filled vs Padmount
This side-by-side comparison helps you see the weight differences at a glance:
| kVA | Dry-Type 3Φ (lbs) | Oil-Filled 3Φ (lbs) | Padmount (lbs) | Oil vs Dry Ratio |
|---|---|---|---|---|
| 75 | 500 | 700 | 640 | 1.40× |
| 150 | 800 | 1,150 | 950 | 1.44× |
| 300 | 1,050 | 1,700 | 1,200 | 1.62× |
| 500 | 1,200 | 2,200 | 1,250 | 1.83× |
| 1,000 | 1,900 | 4,000 | 1,600 | 2.11× |
| 2,500 | 4,500 | 9,000 | 2,400 | 2.00× |
Key Insight: The oil-to-dry weight ratio increases with kVA. At 75 kVA, oil-filled is only 1.4×
heavier. At 1,000 kVA, it’s over 2× heavier. This non-linear relationship is because larger transformers require
proportionally more oil for cooling.
outweigh dry-type by 1.4× to 2.1× depending on kVA rating.
Quick Weight Estimation Formulas
Need a rough weight estimate before looking up exact figures? These rules of thumb have proven reliable in our
manufacturing practice:
For Dry-Type Transformers (Three-Phase)
Weight (lbs) ≈ 42 × kVA^0.56Example: 500 kVA → 42 × 5000.56 ≈ 42 × 29.2 ≈ 1,226 lbs (actual: ~1,200 lbs ✓)
Example: 1,000 kVA → 42 × 10000.56 ≈ 42 × 43.1 ≈ 1,810 lbs (actual: ~1,900 lbs ✓)
For Oil-Filled Transformers (Three-Phase)
Weight (lbs) ≈ 31.5 × kVA^0.71Example: 500 kVA → 31.5 × 5000.71 ≈ 31.5 × 70.8 ≈ 2,230 lbs (actual: ~2,200 lbs ✓)
Example: 1,000 kVA → 31.5 × 10000.71 ≈ 31.5 × 115.8 ≈ 3,648 lbs (actual: ~4,000 lbs, within ±10%)
Shipping Weight Rule
Shipping Weight ≈ 1.1 × Transformer Weight (adds crating/pallet)These formulas are estimates only and should never replace manufacturer data for engineering
calculations. However, they’re invaluable during the budgeting and preliminary planning stage when exact models
haven’t been selected yet.
🔧 Pro Tip from the Factory: When we quote a project, I always add 10% to the catalog weight for
budgeting purposes. This covers the variability between manufacturers and accounts for any last-minute accessories
like surge arresters or cable termination kits that add weight.
Rigging & Handling Guide by Weight Class
Knowing the weight is only half the battle—you also need the right equipment to move it:
| Weight Class | Weight Range | Recommended Equipment | Crew Size |
|---|---|---|---|
| Light | Under 200 lbs | Hand truck or pallet jack | 2 |
| Medium | 200–500 lbs | Forklift (5,000 lb capacity) | 2–3 |
| Heavy | 500–2,000 lbs | Forklift or small crane | 3–4 |
| Very Heavy | 2,000–5,000 lbs | Crane (10-ton) | 4–6 |
| Super Heavy | 5,000+ lbs | Heavy crane (25+ ton) | 6+ specialized |
⚠️ Safety Warning: Never attempt to lift a transformer by its bushings, conduit box, or radiators.
Use only the designated lifting lugs. I’ve seen a 750 kVA unit’s bushing snap when a rigger used it as a lifting
point—the bushing alone costs $3,000 to replace, not counting the downtime.
never lift by bushings, conduit box, or radiators (red).
For complete installation procedures, see our Pole
Mounted Transformer Installation Guide and Pad
Mounted Transformer Guide.
What Affects Transformer Weight?
Seven factors determine actual transformer weight:
| Factor | Effect on Weight | Impact Level |
|---|---|---|
| kVA rating | Higher kVA = heavier core and windings | ⭐⭐⭐⭐⭐ |
| Voltage class | Higher BIL = more insulation mass | ⭐⭐⭐⭐ |
| Cooling type | Oil adds 25-50% vs dry-type | ⭐⭐⭐⭐ |
| Winding material | Copper is 3.3× heavier than aluminum | ⭐⭐⭐ |
| Efficiency rating | Higher efficiency = more core material | ⭐⭐⭐ |
| Enclosure type | NEMA 3R adds 10-15% for weatherproofing | ⭐⭐ |
| Accessories | Tap changer, surge arrester, gauges | ⭐ |
Copper vs Aluminum Impact: A copper-wound 500 kVA transformer weighs roughly 15-20% more than an
identical aluminum-wound unit. However, copper units are physically smaller since copper has better conductivity—so
the weight-to-footprint tradeoff isn’t straightforward. For a detailed comparison, see our article on Transformer Construction: Core Types and Winding Designs.
Frequently Asked Questions
How much does a 100 kVA transformer weigh?
A 100 kVA dry-type three-phase transformer weighs approximately 650 lbs (295 kg). The same rating in
oil-filled is about 850 lbs (386 kg), and a padmount version weighs roughly 750 lbs (340
kg). Single-phase 100 kVA dry-type units weigh around 400 lbs (181 kg).
How much does a 500 kVA transformer weigh?
A 500 kVA three-phase dry-type transformer weighs approximately 1,200 lbs (544 kg). Oil-filled units
weigh about 2,200 lbs (998 kg), requiring crane installation. For full specs, see our 500 kVA
Three-Phase Transformer guide.
How much does a 1000 kVA transformer weigh?
Expect 1,900 lbs (862 kg) for dry-type, rising to 4,000 lbs (1,814 kg) for
oil-filled versions. At this weight class, professional rigging and a 10-ton crane are required. See our 1000 kVA specifications.
Why are oil-filled transformers heavier than dry-type?
Oil-filled transformers carry 25-50% additional weight from the insulating oil itself, plus the heavy steel tank
needed to contain the oil. However, this weight penalty comes with advantages: better heat dissipation allows
smaller core designs, higher voltage ratings, and longer operational life. Learn more about the differences in our
Transformer Oil Complete
Guide.
How do I estimate transformer shipping weight?
Shipping weight is typically 10% higher than the transformer’s listed weight due to crating, pallets, and protective
packaging. For oil-filled units, confirm whether the published weight includes oil—some manufacturers ship “dry”
(without oil) to reduce shipping weight and cost.
What is the weight difference between copper and aluminum wound transformers?
Copper-wound transformers weigh approximately 15-20% more than aluminum-wound equivalents at the same kVA rating. The
density of copper (8.96 g/cm³) is about 3.3× that of aluminum (2.70 g/cm³). Despite the weight penalty, copper’s
higher conductivity means smaller physical dimensions.
Does transformer weight affect installation cost?
Absolutely. Transformers over 500 lbs typically require forklift or crane rental ($500-$2,000/day), and units over
2,000 lbs may need specialized rigging crews ($2,000-$5,000). Always factor in equipment rental when budgeting—it
can add 10-25% to total installation cost.
Conclusion
Transformer weight data is essential for safe installation planning, structural analysis, and logistics budgeting.
Key takeaways from this guide:
- Dry-type transformers are the lightest option—ideal for indoor and upper-floor installations
- Oil-filled transformers weigh 1.4–2.1× more than dry-type at the same kVA
- Padmount transformers include weatherproof enclosure weight—budget for outdoor pad and crane
access - Always request actual shipping weight from your manufacturer—catalog values are typical
references - Use the estimation formulas (Weight ≈ 42 × kVA0.56 for dry-type) for preliminary
planning only
Need Help Selecting the Right Transformer?
Our engineering team at Transformer4U can provide exact weight
specifications, dimensions, and installation guidance for your specific project requirements.
Related Articles
- Transformer Sizing Chart: Complete kVA Selection Guide
- Transformer Full Load Amps Chart: Complete FLA Reference
- Transformer Oil Capacity Chart: Complete kVA Reference
- Distribution Transformer Sizing Calculator
- KVA to Amps Calculator
- Padmount Transformer Sizing Chart
- Oil-Filled Transformer Sizing Chart
- Transformer Nameplate: How to Read Every Detail
About the Author: Tan
Transformer manufacturing specialist at Transformer4U with over 10 years
of experience in transformer design, production, and quality assurance. Every weight figure in this chart has
been cross-referenced with our factory shipping records and manufacturer datasheets.
References
- IEEE C57.12.00 –
General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers - IEEE 693 – Seismic Design of
Substations - NEMA ST 20 – Dry-Type Transformers for General Applications
Disclaimer: This information is provided for educational and reference purposes. Weights shown are typical values
from industry experience. Actual weights vary by manufacturer, voltage class, winding material, and specific
design. Always verify with manufacturer datasheets before making engineering decisions. Data references: IEEE
C57.12.00, manufacturer specifications, and Transformer4U factory records.