Mass Flow Rate Converter
Convert mass flow between kg/s, lb/h, and tons per hour.
What it does
Mass flow tells how much mass passes per time in boilers, feeders, and chemical dosing. American plants quote pounds per hour, metric plants quote kg per second or tonnes per hour. Converting needs exact mass and time factors.
The tool above converts among kg/s, g/s, t/h, lb/s, lb/h, and short ton/h. The defaults convert 1000 lb/h to kg/s, so the page opens showing 0.126 kg/s. Pick new units to update the result and the full list.
The math rests on the exact pound, 0.45359237 kg, and exact time, 3600 seconds per hour. One short ton is 2000 pounds, or 907.18474 kg. One tonne per hour is 1000 kg per 3600 seconds.
Use kg/s for SI balances, lb/h for US burner specs, and t/h for bulk handling. Keep mass flow apart from volume flow: mass needs no density, volume does.
This page shows the factors, one full hand checked example at 1000 lb/h, a reference table, and practice checks that run through the tool.
How to use
- Type the flow number, for example 1000.
- Pick the starting unit in From unit.
- Pick the target unit in To unit.
- Read the main result with unit name.
- Scan the note line for all six units.
- Check ton type: short tons here, not metric tonnes.
Formula
- kg/s
- Base unit.
- lb/h
- US plant unit. 1 lb/h = 0.45359237/3600 kg/s.
- ton/h
- Short tons per hour. 1 ton/h = 907.18474/3600 kg/s.
Tonne t/h uses 1000 kg. Short ton uses 2000 lb. Do not mix them without converting.
Worked example
Example: 1000 lb/h to kg/s
A feeder doses 1000 pounds per hour. Convert to kg/s.
- Write 1000, from lb/h, to kg/s.
- Factor: 1 lb/h = 0.45359237/3600 = 0.000125998 kg/s.
- Multiply: 1000 x 0.000125998 = 0.125998.
- Round to four decimals: 0.126 kg/s.
- Check: 0.126 x 7936.64 = 1000 lb/h near rounding.
- Siblings: 126 g/s and 0.4536 t/h.
Reference table
| Unit | kg/s per unit | Note |
|---|---|---|
| kg/s | 1 | Base |
| g/s | 0.001 | Divide by 1000 |
| t/h | 0.2777778 | 1000 kg per 3600 s |
| lb/s | 0.4535924 | Exact pound |
| lb/h | 0.000126 | Divide by 3600 |
| ton/h | 0.2519958 | 2000 lb per 3600 s |
Limits
- Steady flow only. Batch totals need time multiply.
- Short tons here. Metric tonnes are separate t/h unit.
- No density model. For volume use a volume flow tool.
- Four decimals suit plants. Lab dosing may need more.
Common mistakes
- Mixing short tons with metric tonnes.
- Forgetting per hour to per second divide by 3600.
- Reading lb/s as lb/h, off by 3600 times.
- Using volume GPM factors for mass.
- Typing commas as thousand separators.
Try it yourself
Quick checks. Answers sit tucked under each question.
2.5 t/h in kg/s?
2.5 x 1000/3600 = 0.6944 kg/s.
5 kg/s in lb/h?
5 / 0.000125998 = 39683.2072 lb/h.
Questions
1000 lb/h in kg/s?
0.126 kg/s.
kg/s or lb/h?
SI uses kg/s, US plants often lb/h.
Short or metric ton?
This tool separates ton/h short from t/h metric.
Mass or volume flow?
Mass needs no density. Volume needs fluid density for mass.
Why 3600?
Seconds per hour for per second to per hour shifts.
Four decimals enough?
For plants yes. Labs may keep more digits.