Convert lb/hr to kg/hr or kg/hr to lb/hr, including lb/min, lb/s, lb/day, kg/min, kg/s, and tonne/hr mass flow rates for easy online conversion.
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lb/hr to kg/hr Formula
kg/hr = lb/hr × 0.45359237
Reverse direction:
lb/hr = kg/hr ÷ 0.45359237
- lb/hr — pounds-mass per hour
- kg/hr — kilograms per hour
- 0.45359237 — exact pound-to-kilogram conversion factor
This is a mass flow conversion, not volumetric. The factor is exact by international agreement (1959). If your input uses lb/min, lb/s, or lb/day, the calculator first normalizes to lb/hr (×60, ×3600, ÷24) before converting.
Quick Reference Tables
Common lb/hr values converted to kg/hr:
| lb/hr | kg/hr | tonne/hr |
|---|---|---|
| 10 | 4.536 | 0.0045 |
| 100 | 45.36 | 0.0454 |
| 500 | 226.80 | 0.227 |
| 1,000 | 453.59 | 0.454 |
| 5,000 | 2,267.96 | 2.268 |
| 10,000 | 4,535.92 | 4.536 |
| 50,000 | 22,679.62 | 22.68 |
| 100,000 | 45,359.24 | 45.36 |
Typical mass flow rates by application:
| Application | Range (lb/hr) | Range (kg/hr) |
|---|---|---|
| Lab dosing pump | 1 – 50 | 0.5 – 23 |
| Small steam boiler | 100 – 1,000 | 45 – 454 |
| Commercial boiler | 1,000 – 10,000 | 454 – 4,536 |
| Industrial process heater | 10,000 – 100,000 | 4,536 – 45,359 |
| Utility power boiler | 100,000+ | 45,359+ |
Worked Example
A boiler is rated at 8,500 lb/hr of steam. Convert to kg/hr.
kg/hr = 8,500 × 0.45359237 = 3,855.5 kg/hr (about 3.86 tonne/hr).
FAQ
Is this conversion the same for any fluid?
Yes. lb/hr and kg/hr both measure mass, so the factor 0.45359237 applies regardless of whether the flow is steam, water, oil, or air.
What about lb/hr to kg/s?
Divide kg/hr by 3,600. So 1,000 lb/hr = 453.6 kg/hr = 0.126 kg/s.
Why not just use 0.4536?
For most engineering work the rounded factor is fine. The calculator uses the exact value (0.45359237) to keep large flow rates accurate.
Does temperature or pressure matter?
No. Mass flow does not change with state. Only volumetric flow rates (gpm, m³/hr, scfm) require density corrections.
