Transformer Calculator
Transformer Formulas
Basic Transformer Equation
Vp / Vs = Np / Ns = Is / IpWhere:
- Vp = Primary Voltage
- Vs = Secondary Voltage
- Np = Primary Turns
- Ns = Secondary Turns
- Ip = Primary Current
- Is = Secondary Current
Power Formula
Power (VA) = Vp × Ip = Vs × Is (ideal, no losses)Turns Ratio
Turns Ratio = Np / Ns = Vp / VsStep-Up Transformer
Increases voltage, decreases current. Example: 120V to 480V
Vs = Vp × (Ns / Np) where Ns > NpStep-Down Transformer
Decreases voltage, increases current. Example: 480V to 120V
Vs = Vp × (Ns / Np) where Ns < NpCommon Transformer Ratios
- 480V to 120V: 4:1 ratio
- 240V to 120V: 2:1 ratio
- 208V to 120V: 1.73:1 ratio
- 120V to 24V: 5:1 ratio
- 277V to 120V: 2.3:1 ratio
Transformer Efficiency
Real transformers have losses due to:
- Copper losses (I²R heating)
- Core losses (eddy currents, hysteresis)
- Leakage flux
Typical efficiency: 95-98% for power transformers
About Transformer Calculator
Transformer Calculator - Calculate Voltage & Current Transformation
Calculate transformer voltage, current, turns ratio, and power rating instantly. Essential for electrical engineering and transformer sizing applications.
Transformer Formulas
Basic Transformer Equation
Vp / Vs = Np / Ns = Is / IpWhere:
- Vp = Primary Voltage
- Vs = Secondary Voltage
- Np = Primary Turns
- Ns = Secondary Turns
- Ip = Primary Current
- Is = Secondary Current
Power (VA) Formula
Power = Vp × Ip = Vs × Is (single phase)
Power = V × I × 1.732 (three phase)Turns Ratio
Turns Ratio = Np / Ns = Vp / VsCommon Transformer Applications
| Type | Primary | Secondary | Ratio | Common Use |
|---|---|---|---|---|
| Step-Down | 480V | 120/240V | 4:1 | Commercial to residential |
| Step-Down | 240V | 120V | 2:1 | Residential lighting |
| Step-Down | 120V | 24V | 5:1 | HVAC control, doorbells |
| Step-Up | 120V | 480V | 1:4 | Equipment power |
| Distribution | 13.8kV | 480V | 28.75:1 | Utility to building |
Related Calculators
Calculate concrete volume for slabs, footings, columns, and tubes. Get accurate estimates in cubic yards, cubic meters, and bags needed.
Calculate paint and primer needed for interior and exterior projects. Estimate gallons, coats, and costs for walls, ceilings, and trim.
Calculate roofing materials, shingles, and costs instantly. Estimates for gable, hip, and flat roofs with waste factor included.
Calculate tile needs for floors, walls, and backsplashes. Get accurate estimates of tiles needed including waste percentage and grout coverage.
Calculate concrete blocks and mortar needed for walls. Estimate blocks, mortar bags, and costs for standard and custom block sizes.
Calculate concrete volume for slabs, patios, and footings. Get accurate estimates in cubic yards, bags, and cost for concrete pours.
Calculate sand volume and weight for construction projects. Estimate sand needed for concrete, landscaping, and playgrounds.
Calculate gravel volume and weight for driveways, pathways, and landscaping. Estimate tons and cubic yards needed.
Calculate asphalt needed for driveways, parking lots, and roads. Estimate hot mix asphalt volume in tons and cubic yards.
Calculate wallpaper rolls needed for any room. Estimate wallpaper, account for pattern repeats, doors, and windows.
Calculate carpet needed for rooms and stairs. Estimate carpet in square yards and square feet with waste factor included.
Calculate fence materials including posts, panels, pickets, and concrete needed. Estimates for wood, vinyl, and chain link fences.
Calculate decking materials including deck boards, joists, and screws. Estimate composite, wood, and PVC decking needs.
Calculate siding materials needed for your home. Estimate vinyl, wood, fiber cement siding in squares and linear feet.
Calculate drywall sheets needed for walls and ceilings. Estimate materials including tape, mud, and screws for your project.
Calculate flooring materials for hardwood, laminate, vinyl, carpet, and tile. Estimate square footage, boxes needed, and project costs.
Calculate your GPA instantly. Support for weighted and unweighted GPA. Multiple courses, cumulative GPA, and grade tracking.
Calculate your final grade with our free grade calculator. Determine what you need on your final exam to achieve your desired course grade.