Quad to Joule Converter
Convert quads to joules with our free online energy converter.
Quick Answer
1 Quad = 1.055060e+18 joules
Formula: Quad × conversion factor = Joule
Use the calculator below for instant, accurate conversions.
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All conversion formulas on UnitsConverter.io have been verified against NIST (National Institute of Standards and Technology) guidelines and international SI standards. Our calculations are accurate to 10 decimal places for standard conversions and use arbitrary precision arithmetic for astronomical units.
Quad to Joule Calculator
How to Use the Quad to Joule Calculator:
- Enter the value you want to convert in the 'From' field (Quad).
- The converted value in Joule will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Energy category.
- Click the swap button (⇌) to reverse the conversion direction.
How to Convert Quad to Joule: Step-by-Step Guide
Converting Quad to Joule involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
J = quad × 1055060000000000000Example Calculation:
1 quad = 1.055060e+18 J
Disclaimer: For Reference Only
These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.
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Need to convert to other energy units?
View all Energy conversions →What is a Quad and a Joule?
1 quad = 1.055×10¹⁸ joules (J)
and Standards
SI Definition
The joule is the SI derived unit of energy, work, and heat, defined as:
1 joule = the energy transferred when a force of 1 newton acts through a distance of 1 meter
Mathematically:
- 1 J = 1 N·m (newton-meter)
- 1 J = 1 kg·m²/s² (SI base units)
- 1 J = 1 W·s (watt-second)
- 1 J = 1 Pa·m³ (pascal-cubic meter)
Multiple Equivalent Definitions
Mechanical work: 1 J = work done moving an object 1 meter against 1 newton force
Electrical energy: 1 J = energy dissipated passing 1 ampere through 1 ohm resistance for 1 second (1 J = 1 A² · Ω · s = 1 V · A · s)
Kinetic energy: 1 J = kinetic energy of a 2 kg mass moving at 1 m/s (KE = ½mv² = ½ × 2 × 1² = 1 J)
Gravitational potential energy: 1 J = energy to lift ~102 grams by 1 meter on Earth (PE = mgh = 0.102 kg × 9.8 m/s² × 1 m ≈ 1 J)
Thermal energy: 1 J ≈ 0.239 calories (energy to raise 0.239 grams of water by 1°C)
2019 SI Redefinition
The 2019 SI revision redefined the joule based on exact fundamental constants:
- Planck constant (h): Exactly 6.62607015 × 10⁻³⁴ J·s
- Speed of light (c): Exactly 299,792,458 m/s
- Caesium hyperfine frequency: Exactly 9,192,631,770 Hz
Since the joule is defined in terms of kilogram, meter, and second, and these are now defined via fundamental constants, the joule has absolute stability independent of physical artifacts.
Standard Multiples
Kilojoule (kJ): 1 kJ = 1,000 J
- Typical for food energy (1 food Calorie = 4.184 kJ)
- Small appliance energy consumption
Megajoule (MJ): 1 MJ = 1,000,000 J = 1,000 kJ
- Vehicle fuel energy (1 liter gasoline ≈ 32 MJ)
- Industrial processes, home daily energy use
Gigajoule (GJ): 1 GJ = 1,000,000,000 J = 1,000 MJ
- Large-scale energy systems
- Natural gas (1 cubic meter ≈ 38 MJ, 1 therm = 105.5 MJ)
Terajoule (TJ): 1 TJ = 10¹² J
- Power plant output (per day/month)
- National energy statistics
Note: The Quad is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Joule belongs to the imperial/US customary system.
History of the Quad and Joule
and Evolution
The Mechanical Equivalent of Heat (1840s-1850s)
James Prescott Joule (1818-1889), an English brewer and amateur scientist, conducted groundbreaking experiments demonstrating that mechanical work and heat are equivalent.
Famous paddle-wheel experiment (1843-1850): Joule built apparatus where falling weights drove paddles that stirred water in an insulated container. He precisely measured:
- Mechanical work input (weight × distance fallen)
- Temperature rise of water
- Established ratio: ~772 foot-pounds of work = 1 BTU of heat
- Modern equivalent: 4.184 joules = 1 calorie
Joule's work was initially met with skepticism but eventually revolutionized thermodynamics by unifying heat and mechanical energy under the first law of thermodynamics (conservation of energy).
Lord Kelvin (William Thomson) and Rudolf Clausius incorporated Joule's findings into the foundation of thermodynamics in the 1850s-1860s.
Adoption as a Unit (1882)
The British Association for the Advancement of Science formally adopted "joule" as the unit of work at its 1882 meeting, honoring James Prescott Joule's contributions. The joule was defined as 10⁷ ergs (the CGS energy unit).
Early definition: 1 joule = 10⁷ erg = 10⁷ g·cm²/s²
This established the joule in the meter-kilogram-second (MKS) system, precursor to SI.
International System of Units (1960)
The 11th General Conference on Weights and Measures (CGPM) in 1960 established the International System of Units (SI), designating the joule as the official SI unit for energy, work, and heat.
Unified energy unit: The joule replaced multiple historical units:
- Calorie (thermochemistry, nutrition)
- Erg (CGS physics)
- Foot-pound (engineering)
- Watt-hour (electricity)
- BTU (heating/cooling)
Despite SI adoption, many of these units persist in specific contexts (food Calories, kWh for electricity billing, BTU for HVAC).
Modern Precision (1990s-2019)
1990 redefinition: Linked to the volt and ohm through quantum electrical standards (Josephson effect and quantum Hall effect), enabling unprecedented precision.
2019 SI revision: Redefined the joule via exact fundamental constants (Planck constant, speed of light), eliminating dependence on physical prototypes. This "New SI" provides ultimate stability—joule can be reproduced anywhere in the universe using only constants and measurement equipment.
Common Uses and Applications: quads vs joules
Explore the typical applications for both Quad (imperial/US) and Joule (imperial/US) to understand their common contexts.
Common Uses for quads
Used in physics, engineering, energy systems, and scientific calculations where this energy scale is appropriate for the application.
When to Use joules
Physics and Science
The joule is the universal energy unit in scientific research:
Mechanics: Kinetic energy (KE = ½mv²), potential energy (PE = mgh), work (W = F·d)
Thermodynamics: Heat transfer, enthalpy, internal energy, entropy (S units: J/K)
Electromagnetism: Electrical energy (E = V·I·t), magnetic energy (E = ½LI²), capacitor energy (E = ½CV²)
Quantum mechanics: Energy levels in atoms/molecules (though electronvolts often preferred)
Relativity: Mass-energy equivalence E = mc² (in joules when using SI units)
Engineering Applications
Engineers use joules across all disciplines:
Mechanical engineering: Impact energy, spring energy (E = ½kx²), rotational energy (E = ½Iω²)
Civil engineering: Structural load energy, seismic energy absorption
Aerospace engineering: Rocket propulsion energy, orbital energy calculations
Chemical engineering: Heat of reaction, activation energy, process energy requirements
Materials science: Fracture energy, strain energy density
Electrical and Electronics
Joules quantify electrical energy consumption:
Power consumption: Energy (J) = Power (W) × Time (s)
- 100W light bulb for 1 hour = 100 × 3,600 = 360,000 J = 360 kJ
Battery capacity: Often listed in watt-hours (Wh), convert to joules by × 3,600
- 10 Wh battery = 10 × 3,600 = 36,000 J = 36 kJ
Capacitor energy: E = ½CV² (where C in farads, V in volts, E in joules)
Energy efficiency: Comparing joules input vs. joules output determines efficiency percentage
Nutrition and Food Science
Many countries mandate both kilojoules and Calories on nutrition labels:
Australia/New Zealand: Kilojoules (kJ) primary, Calories secondary
European Union: Often lists both kJ and kcal
Conversion: 1 food Calorie (kcal) = 4.184 kJ
Example: 500 kJ = 500 ÷ 4.184 ≈ 120 kcal (Calories)
Climate and Energy Policy
Joules (typically in TJ, PJ, EJ) measure large-scale energy:
National energy consumption: Reported in exajoules (EJ = 10¹⁸ J) annually
- World primary energy: ~600 EJ/year
- United States: ~100 EJ/year
Carbon footprint: kg CO₂ per GJ of energy source
Renewable energy: Solar irradiance (W/m² → J/m² over time)
Energy intensity: Economic output per joule consumed (GDP/GJ)
Sports and Exercise Science
Joules measure human energy expenditure:
Metabolic equivalent (MET): 1 MET = ~4.184 kJ/hour per kg body weight at rest
Cycling power meters: Measure work in kilojoules per ride
Weightlifting: Work = weight × height × 9.8 (in joules)
- Deadlift 100 kg to 1 meter height = 100 × 9.8 × 1 = 980 J
Running economy: Joules per meter traveled
Additional Unit Information
About Quad (quad)
How do I convert quad to joules?
Formula: J = quad × 1.055×10¹⁸
How do I convert quad to kWh?
To convert to kilowatt-hours, first convert to joules, then divide by 3,600,000.
What is Quad used for?
Quad is used in contexts where the energy scale makes it convenient compared to very large or very small joule values. It provides a practical measurement unit for specific applications.
About Joule (J)
How do I convert joules to calories?
Formula: calories = joules ÷ 4.184
Examples:
- 4,184 J = 1,000 small calories = 1 kcal (food Calorie)
- 100 J = 100 ÷ 4.184 ≈ 23.9 calories
- 1,000 J = 1,000 ÷ 4.184 ≈ 239 calories
For food Calories (kcal): joules ÷ 4,184 = kcal
- 418,400 J ÷ 4,184 = 100 kcal (food Calories)
How do I convert joules to kWh?
Formula: kWh = joules ÷ 3,600,000
Why 3,600,000?: 1 kWh = 1,000 watts × 3,600 seconds = 3,600,000 joules
Examples:
- 3,600,000 J = 1 kWh
- 1,800,000 J = 0.5 kWh
- 108,000,000 J = 30 kWh (typical home daily use)
How much energy is 1 joule?
Physical examples:
- Lifting 100 grams (small apple) 1 meter against Earth's gravity
- 1 watt of power for 1 second
- Kinetic energy of 2 kg mass moving at 1 m/s
- Energy to heat 0.24 grams of water by 1°C
Perspective: 1 joule is small—about the energy in a single heartbeat. Practical applications typically use kilojoules (kJ), megajoules (MJ), or kilowatt-hours (kWh).
What is the relationship between watts and joules?
Power (watts) = Energy (joules) ÷ Time (seconds)
Or equivalently: Energy (joules) = Power (watts) × Time (seconds)
Definition: 1 watt = 1 joule per second (W = J/s)
Examples:
- 100W light bulb for 10 seconds = 100 × 10 = 1,000 J = 1 kJ
- 1,000W microwave for 2 minutes = 1,000 × 120 = 120,000 J = 120 kJ
- 1W for 1 hour = 1 × 3,600 = 3,600 J = 3.6 kJ
Takeaway: Watts measure the rate of energy use; joules measure the total amount of energy.
Why do energy bills use kWh instead of joules?
Historical reasons: Kilowatt-hours (kWh) became standard for electricity billing before SI joule adoption (1960).
Convenient numbers: Home electricity typically measures 10-50 kWh/day, equivalent to 36-180 MJ/day. Using joules would require large numbers (millions).
Industry inertia: Billions of meters and billing systems use kWh; switching would require enormous infrastructure investment.
Conversion: 1 kWh = 3,600,000 J = 3.6 MJ
Both valid: kWh and MJ are both acceptable SI-compatible units for electrical energy.
How many joules are in a food Calorie?
1 food Calorie (capital C, kilocalorie) = 4,184 joules = 4.184 kilojoules
Important distinction:
- Small calorie (cal): 4.184 J
- Food Calorie (Cal, kcal): 4,184 J = 4.184 kJ
Examples:
- 100 Calorie snack = 418,400 J = 418.4 kJ
- 2,000 Calorie daily intake = 8,368,000 J = 8.368 MJ
- Banana (105 Calories) = 439,320 J ≈ 439 kJ
Labeling variation: Some countries (Australia, EU) show energy in both kJ and kcal.
What's the difference between joules and electronvolts?
Both measure energy but use vastly different scales:
Joule (J): SI unit for macroscopic energy (mechanical, thermal, electrical)
Electronvolt (eV): Atomic-scale energy unit (energy gained by electron crossing 1 volt)
Conversion: 1 eV = 1.602 × 10⁻¹⁹ J (extremely tiny in macroscopic terms)
Usage:
- Joules: Everyday physics, engineering, household energy
- Electronvolts: Atomic physics, chemistry, particle physics, semiconductors
Example: Visible light photon ≈ 2 eV ≈ 3.2 × 10⁻¹⁹ J
How do joules relate to kinetic energy?
Kinetic energy formula: KE = ½mv²
Where:
- m = mass (kg)
- v = velocity (m/s)
- KE = kinetic energy (joules)
Examples:
- 1 kg at 1 m/s: KE = ½ × 1 × 1² = 0.5 J
- 10 kg at 10 m/s: KE = ½ × 10 × 10² = 500 J
- 1,000 kg (small car) at 20 m/s (72 km/h): KE = ½ × 1,000 × 20² = 200,000 J = 200 kJ
- 70 kg person at 3 m/s (jogging): KE = ½ × 70 × 3² = 315 J
Note: Kinetic energy grows with velocity squared, so doubling speed quadruples energy.
Can you create or destroy joules?
No, energy (in joules) is conserved according to the first law of thermodynamics (conservation of energy).
Energy can only transform:
- Mechanical → thermal (friction converts motion to heat)
- Chemical → thermal (combustion releases heat)
- Electrical → mechanical (motors convert electricity to motion)
- Nuclear → thermal → mechanical → electrical (nuclear power plants)
Total joules remain constant in isolated systems, though energy may become less useful (second law: entropy increases).
Mass-energy equivalence: Einstein's E = mc² shows mass can convert to energy and vice versa, but total mass-energy (in joules) is conserved.
How many joules does a human use per day?
Basal metabolism (resting): ~7,000,000-9,000,000 J (7-9 MJ = 1,700-2,200 kcal)
Total daily energy expenditure (including activity):
- Sedentary: ~8,000,000-10,000,000 J (8-10 MJ = 2,000-2,400 kcal)
- Moderate activity: ~10,000,000-12,000,000 J (10-12 MJ = 2,400-3,000 kcal)
- Very active: ~12,000,000-16,000,000 J (12-16 MJ = 3,000-4,000 kcal)
- Elite athlete training: ~16,000,000-33,000,000 J (16-33 MJ = 4,000-8,000 kcal)
Energy sources: Carbohydrates (17 kJ/g), proteins (17 kJ/g), fats (37 kJ/g)
Efficiency: Human body ~20-25% efficient at converting food energy to mechanical work; rest becomes heat.
Conversion Table: Quad to Joule
| Quad (quad) | Joule (J) |
|---|---|
| 0.5 | 527,530,000,000,000,000 |
| 1 | 1,055,060,000,000,000,000 |
| 1.5 | 1,582,590,000,000,000,000 |
| 2 | 2,110,120,000,000,000,000 |
| 5 | 5,275,300,000,000,000,000 |
| 10 | 10,550,600,000,000,000,000 |
| 25 | 26,376,500,000,000,000,000 |
| 50 | 52,753,000,000,000,000,000 |
| 100 | 105,506,000,000,000,000,000 |
| 250 | 263,765,000,000,000,000,000 |
| 500 | 527,530,000,000,000,000,000 |
| 1,000 | 1,055,060,000,000,000,000,000 |
People Also Ask
How do I convert Quad to Joule?
To convert Quad to Joule, enter the value in Quad in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our energy converter page to convert between other units in this category.
Learn more →What is the conversion factor from Quad to Joule?
The conversion factor depends on the specific relationship between Quad and Joule. You can find the exact conversion formula and factor on this page. Our calculator handles all calculations automatically. See the conversion table above for common values.
Can I convert Joule back to Quad?
Yes! You can easily convert Joule back to Quad by using the swap button (⇌) in the calculator above, or by visiting our Joule to Quad converter page. You can also explore other energy conversions on our category page.
Learn more →What are common uses for Quad and Joule?
Quad and Joule are both standard units used in energy measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our energy converter for more conversion options.
For more energy conversion questions, visit our FAQ page or explore our conversion guides.
Helpful Conversion Guides
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📚 How to Convert Units
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🔢 Conversion Formulas
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⚖️ Metric vs Imperial
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⚠️ Common Mistakes
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All Energy Conversions
Other Energy Units and Conversions
Explore other energy units and their conversion options:
- Kilojoule (kJ) • Quad to Kilojoule
- Megajoule (MJ) • Quad to Megajoule
- Gigajoule (GJ) • Quad to Gigajoule
- Watt-hour (Wh) • Quad to Watt-hour
- Kilowatt-hour (kWh) • Quad to Kilowatt-hour
- Megawatt-hour (MWh) • Quad to Megawatt-hour
- Calorie (cal) • Quad to Calorie
- Kilocalorie (kcal) • Quad to Kilocalorie
- British Thermal Unit (BTU) • Quad to British Thermal Unit
- Therm (therm) • Quad to Therm
Verified Against Authority Standards
All conversion formulas have been verified against international standards and authoritative sources to ensure maximum accuracy and reliability.
National Institute of Standards and Technology — Fundamental physical constants and unit conversions
Bureau International des Poids et Mesures — International System of Units (SI) definitions and standards
International Organization for Standardization — Quantities and units international standards series
Last verified: February 19, 2026