DC CURRENT · COPPER LOSS · AMPERE-TURNS
DC Solenoid Coil Calculator
Compare current, copper loss and ampere-turns at a fixed DC voltage. Start with resistance, wire dimensions or target electrical power, then see how an entered wire temperature changes the result.
Compare the electrical operating points
Results update as you editFROM INPUT TO SPECIFICATION
How to use this calculator
Start with a known design requirement, check the assumptions, and keep a record of the values you used.
Choose your starting specification
Use measured total resistance at 20 °C, estimate resistance from bare wire diameter and wire length, or work back from target electrical power at 20 °C.
Set voltage and copper temperature
Enter the fixed DC terminal voltage and the winding temperature you want to compare. Add the turn count if you also want ampere-turns.
Review the electrical trade-offs
Compare resistance, current and power at 20 °C and the selected temperature. Save the table with your mechanical, thermal and duty-cycle requirements for review.
METHOD & SCOPE
What the calculation means.
Hold the voltage fixed. Compare resistance.
Copper resistance changes with the entered wire temperature. Current and electrical power are calculated at the same fixed DC terminal voltage for each comparison point.
Wire mode derives R20 from copper area and total wire length, including two equal leads. Resistance mode already includes the full copper path and does not add the leads again. Power mode derives R20 = V²/P20.
Temperature is an input, not a predicted rise
The comparison shows steady DC electrical values at specified, uniform copper temperatures. It does not model heat dissipation, warm-up time, PWM, a current regulator or duty-cycle averaging.
Ampere-turns describe winding excitation. Force and stroke require the magnetic circuit, air gap, plunger, materials and mechanical load. An entered temperature or power does not establish a continuous-duty or insulation rating.
DESIGN QUESTIONS
Before you build.
Why does current fall when I enter a higher winding temperature?
Copper resistance increases with temperature. With DC terminal voltage held fixed, a higher resistance means lower current and lower electrical power. A current-regulated drive behaves differently and is outside this calculator.
Does the selected temperature predict how hot my coil will become?
No. You supply the copper temperature as a comparison condition. Actual temperature rise depends on heat dissipation, mounting, ambient conditions, enclosure, duty cycle and the complete assembly. The entered temperature is not a product rating.
Can ampere-turns predict the solenoid’s force?
Ampere-turns are current multiplied by winding turns. Force also depends on the magnetic circuit, air gap, plunger position, magnetic material and mechanical load. This tool does not calculate force, stroke or response time.
When are lead length and copper weight included?
Wire mode adds two leads of the entered length to the winding wire length and calculates bare-copper weight. The default is 60 mm per lead. In resistance mode, enter the total resistance including leads; the tool does not add a second lead allowance.
CONTINUE YOUR DESIGN
The next step for your coil.
Keep the calculation with your drawing and target specifications when discussing a coil design.