Energy Calculator

Calculate kinetic, potential, or total energy from mass, velocity, and height.

By Konstantin Iakovlev · Updated April 2026 · Source: Khan Academy

Energy Type

Energy

125.00 J

Energy Calculation

FormulaKE = 0.5 x m x v^2
Energy125.00 Joules
In kJ0.1250 kJ

Use the Energy Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.

How It Works

Mass, velocity, and height are all you need to pin down an object's kinetic, potential, or total mechanical energy. The stakes are real across disciplines: in aerospace, squeezing fuel efficiency on a 2026 Mars mission can save billions, while in renewable energy the same calculations gauge a wind turbine's power output. Quantifying energy is what lets engineers design systems precisely and run the safety analyses that head off costly failures.

Three physics relationships drive the results. Kinetic Energy (KE), the energy of motion, comes from 0.5 * mass * velocity^2. Potential Energy (PE) follows mass * gravitational acceleration * height, with gravitational acceleration on Earth taken as roughly 9.81 m/s^2. Total Mechanical Energy is just KE and PE added together.

Unit consistency is where results go wrong; mixing grams for mass with kilometers per hour for velocity will hand you nonsense. The gravitational acceleration constant also gets dropped or misapplied, particularly when potential energy is being worked out for other planetary environments. This tool stays within mechanical energy and makes no attempt to capture thermal, chemical, or other forms.

Example: Drone Battery Life Estimation for 2026 Delivery

  1. 1 A delivery drone with a mass of 5 kg is flying at a velocity of 20 m/s at an altitude of 100 meters above the ground. We want to calculate its total mechanical energy to estimate battery drain.
  2. 2 First, calculate Kinetic Energy (KE): 0.5 * 5 kg * (20 m/s)^2 = 1000 Joules. Next, calculate Potential Energy (PE): 5 kg * 9.81 m/s^2 * 100 m = 4905 Joules. Finally, Total Energy = KE + PE = 1000 J + 4905 J = 5905 Joules.
  3. 3 The drone's total mechanical energy is 5905 Joules.
  4. 4 This energy value is critical for drone manufacturers like DJI or Amazon Prime Air, as it directly impacts battery life and flight duration. For instance, if a drone's battery holds 50,000 Joules, this single maneuver consumes roughly 11.8% of its total capacity, informing flight planning for efficient 2026 package deliveries.

Source: Khan Academy · Last updated: April 2026

Frequently Asked Questions

What is the formula for kinetic energy?
Kinetic energy equals one-half times mass times velocity squared (KE = 1/2 mv^2). The unit is joules (J) when mass is in kilograms and velocity in meters per second. Doubling the velocity quadruples the kinetic energy.
What is the difference between kinetic and potential energy?
Kinetic energy is the energy of motion, while potential energy is stored energy due to position or configuration. Gravitational potential energy equals mass times gravity times height (PE = mgh). Total mechanical energy is the sum of both.
How do I convert between joules and other energy units?
One joule equals 0.239 calories, 0.000278 watt-hours, or 0.738 foot-pounds. One kilowatt-hour equals 3,600,000 joules. One food calorie (kcal) equals 4,184 joules.

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