Convert Horsepower-hours (Hph) to Joules (J)
1 horsepower-hour equals 2684520 Joules.
Formula:
J = Hph × 2684520
Horsepower-hour to Joule Converter
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Result
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Recent Conversions
How to Convert Horsepower-hour to Joule
1 horsepower-hour = 2684520 Joules
Joule = Horsepower-hour × 2684520
Example: 1 Hph × 2684520 = 2684520 J
Reverse Conversion
To convert Joules back to horsepower-hours:
- Remember, 1 joule equals 3.72506 × 10-7 horsepower-hours.
- To convert 2684520 J to Hph, multiply
2684520 x 3.72506 × 10-7, resulting in1 Hph.
Common Horsepower-hour to Joule Conversions
| Horsepower-hour | Joule | Actions |
|---|---|---|
| 0.1 horsepower-hours | 268452 Joules | |
| 12 horsepower-hours | 1342260 Joules | |
| 1 horsepower-hour | 2684520 Joules |
| Horsepower-hour | Joule | Actions |
|---|---|---|
| 5 horsepower-hours | 1.34226 × 107 Joules | |
| 10 horsepower-hours | 2.68452 × 107 Joules | |
| 100 horsepower-hours | 2.68452 × 108 Joules |
Horsepower-hours to Joules Conversion Table
Reference table with common horsepower-hours to joules conversions. All values calculated with high precision.
Horsepower-hours to Joules Table
0.0001 to 12
Horsepower-hours to Joules Table
1 to 100000
Joules to Horsepower-hours Table
1000 to 5000000
Joules to Horsepower-hours Table
10000000 to 1 × 1012
Definition of Horsepower-hour
- Definition
- Energy of one mechanical horsepower sustained for one hour.
- Reference factor
- 1 hp·h ≈ 2.68452 MJ
- Sources
- NIST SP 1038
Definition of Joule
- Definition
- SI unit of energy: 1 J = 1 N·m = 1 kg·m²·s⁻².
- Notes
- Used universally in physics, chemistry, and engineering.
- Sources
- BIPM — SI Brochure
About the Horsepower-hour
Facts & Uses
- Mechanical energy from sustaining 1 hp for one hour: 1 hp·h ≈ 2.68452 MJ ≈ 0.7457 kWh; conversely 1 kWh ≈ 1.341 hp·h.
- Appears in rail traction, industrial drive accounting, and historic engine testing datasets (brake work, shaft work).
- Connects with BSFC (brake-specific fuel consumption) when translating fuel flow to useful work over time.
- Be mindful of horsepower definitions (mechanical hp vs. metric PS); conversions impact hp·h totals and benchmarking.
Curiosities
- James Watt popularized horsepower via 550 ft·lbf/s; integrating over 3600 s yields the hp·h energy unit.
- Classic relation: hp = (torque (ft·lbf) × rpm) / 5252; integrating power over time gives energy in hp·h.
- Not an SI unit; modern metering prefers kWh or J, but hp·h persists in legacy asset accounting.
- Some historical locomotive leasing contracts tracked equipment usage in horsepower-hours as a settlement metric.
Sources
About the Joule
Facts & Uses
- SI unit of energy: 1 J = 1 N·m = 1 W·s = 1 C·V = 1 Pa·m³; ubiquitous in mechanics, thermodynamics, electromagnetism, and chemistry.
- Common engineering scales: kJ, MJ, GJ for fuels, heating/cooling loads, and process energy.
- Everyday intuition: lifting ~1 N through 1 m ≈ 1 J; a 10 Wh battery stores ≈ 36,000 J for devices/IoT.
- Key links: 1 kWh = 3.6 × 10⁶ J; 1 eV = 1.602176634×10⁻¹⁹ J (exact) via the fixed elementary charge.
Curiosities
- Joule heating (I²R) connects electrical losses to thermal energy in conductors and electronics.
- Although both use N·m, torque (vector, moment) and energy (scalar, work) are physically distinct.
- Compression/expansion work in gases is often expressed as Pa·m³ (= J), linking pressure–volume integrals to energy.
- Named for James P. Joule, who quantified the mechanical equivalent of heat, bridging thermal and mechanical domains.
Sources
Frequently Asked Questions
How many Joules are in one horsepower-hour?
One horsepower-hour equals 2684520 Joules. To convert, multiply the horsepower-hour value by 2684520. For the reverse, divide the joule value by 2684520 (or multiply by 3.72506 × 10-7).
What is 2.1 horsepower-hours in Joules?
2.1 horsepower-hours = 5637500 Joules. This is one of the most commonly searched conversions for this pair.
How precise is the horsepower-hour-to-joule conversion?
The factor 2684520 is accurate to 6 significant figures, derived from international measurement standards. Our calculator uses full precision internally.
Looking for the reverse? Convert Joule to Horsepower-hour
Related Energy Converters
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Related in other categories:
- Watts to Kilowatts — Power = energy ÷ time (1 W = 1 J/s)
Conversion factors verified against NIST, BIPM, ISO 80000-4
1 cal_IT = 4.1868 J by definition (BIPM/ITS-90).
Last reviewed: April 2026
