Heat Output Conversion Calculator

Pick a unit, enter heat output, convert instantly. Add run hours to see energy totals. Use results to size heaters and protect seedlings safely.

Calculator

Use nameplate rating for heaters or warmers.
Used to estimate delivered energy over time.
Set lower if losses reduce useful heat.

Example Data Table

Heat Output From To Delivered Heat Converted (Delivered)
1500 Watts BTU/hr 100% 5,118.21 BTU/hr
10 kW Watts 90% 9,000.00 W
12,000 BTU/hr kW 85% 2.99 kW
5000 kJ/hr Watts 100% 1,388.89 W
Examples are rounded for readability. Your selected decimals may differ.

Formula Used

Power conversion using watts as the base
W = Value × (From Unit → W)
Converted = W ÷ (To Unit → W)
Delivered heat adjustment
Delivered W = W × (Delivered Heat % ÷ 100)
Energy over time (optional)
Energy (J) = Delivered W × Hours × 3600
kWh = J ÷ 3,600,000
The conversion factors are engineering-standard approximations. Use calibrated values if your design spec requires tighter tolerances.

How to Use This Calculator

  1. Enter your heater or warmer output value.
  2. Select the unit shown on the equipment label.
  3. Choose the unit you want for comparison or planning.
  4. Optional: add run hours to estimate delivered energy.
  5. Optional: reduce delivered heat to reflect real losses.
  6. Click Convert to view results above this form.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.