Science & Engineering

Inductor Calculator

Find the energy stored in an inductor's magnetic field. Enter the inductance in millihenries and the current in amperes, and the tool returns the stored energy in joules using E = one-half L I squared. Free and browser-based.

What this calculator does

The Inductor Calculator estimates your result instantly from the values you enter, using standard science & engineering formulas. Find the energy stored in an inductor's magnetic field. Enter the inductance in millihenries and the current in amperes, and the tool returns the stored energy in joules using E = one-half L I squared. Free and browser-based. Calculations run in your browser, so nothing you type is sent to a server, and the output is an estimate rather than a certified or official figure.

Inductor Energy Calculator

Result

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Energy Stored (J)

About Inductor Calculator

The Inductor Energy Calculator works out how much energy an inductor holds in its magnetic field. You enter the inductance in millihenries and the current in amperes; the tool converts the inductance to henries and applies E = ½LI².

The energy is reported in joules, rounded to six decimal places.

Formula & Mathematical Calculation

Energy Stored (J) = f(Inductance (mH), Current (A))

Calculated according to standard science formulas implemented in the calculator core.

Calculation Example

With an inductance of 10 mH (0.01 H) and a current of 2 A:

E = ½ × 0.01 × 2² = 0.5 × 0.01 × 4 = 0.02 J

Key Benefits

  • Calculates stored magnetic energy from inductance and current
  • Converts the inductance from millihenries to henries automatically before computing
  • Applies E = one-half L I squared, the standard inductor energy formula
  • Free, runs in the browser, and needs no sign-up

How to Use this Calculator

  1. Enter the inductance
    Type the inductance in millihenries into the Inductance (mH) field, for example 10.
  2. Enter the current
    Type the current in amperes into the Current (A) field, such as 2.
  3. Calculate
    Select Calculate to see the energy stored in joules, rounded to six decimals.

Assumptions & Limitations

What the calculation assumes

  • Every value you enter is treated as an exact, known amount.
  • Any rate or interval you enter is assumed to hold for the whole period unless the form asks for it separately.
  • Results use standard published formulas and account only for the values entered above.
  • Rounding is applied for display; the underlying calculation uses your full precision.
  • Results are returned in the same units you enter, unless the tool states the output unit.

What it does not cover

  • Inductor Calculator produces a calculated result for reference and learning, not a certified or official measurement.
  • Real-world outcomes differ when tolerances, rounding rules or local standards apply.
  • Definitions and standards vary by region and change over time; verify the convention that applies to your case.
  • Figures are only as accurate as the inputs you supply — check them before acting on the result.
  • For work where the result carries real consequences, confirm it against an authoritative source.

Frequently Asked Questions

Enter it in millihenries. The tool multiplies your entry by 0.001 to convert to henries before applying the energy formula, so 10 in the field means 10 mH.

It uses E = one-half times L times I squared, where L is the inductance in henries and I is the current in amperes, giving energy in joules.

The stored energy is proportional to the square of the current, so doubling the current raises the stored energy by a factor of four for the same inductor.

It can, but because the current is squared the sign does not change the result; only its magnitude matters. Inductance, however, cannot be negative.

Free to use, no account needed. Calculations run in your browser, so nothing you type is sent to a server. Results are estimates — how we build and check our calculators.