kW to BTU Calculator

Formula used

How to use this calculator

1. Enter the power value in kilowatts (kW).
2. Select the output time basis you need.
3. Choose rounding so results match your reports.
4. Add an optional context note for documentation.
5. Press Convert to display the result above.
6. Download CSV or PDF for submittals and records.

Example data table

Professional guide

1) Why kW and BTU matter on sites

Construction teams compare electrical power and thermal loads when selecting HVAC equipment, generators, heaters, and temporary conditioning. Kilowatts describe power, while BTU per hour describes heat rate. Converting between them supports quick checks during procurement, submittals, and coordination.

2) Standard conversion data

The calculator uses a fixed factor: 1 kW equals 3412.141633 BTU/h. For example, 3.5 kW converts to about 11,942.50 BTU/h. This helps translate equipment labels when one datasheet lists kW and another lists BTU/h.

3) Time bases and reporting

BTU/h is the most common HVAC capacity unit, but some reports require BTU/min, BTU/s, or BTU/day. The tool converts from the BTU/h result using 60 minutes per hour, 3600 seconds per hour, and 24 hours per day, keeping math consistent across schedules.

4) Practical sizing checkpoints

A small office heater at 1.5 kW is about 5118 BTU/h, while 10 kW is about 34,121 BTU/h. These checkpoints help validate whether loads seem reasonable for temporary heat, site trailers, break rooms, and equipment enclosures before ordering fuel or power.

5) Electrical input versus thermal output

For resistive heaters, electrical input and heat output are close, so kW to BTU/h is a direct translation of heat rate. For heat pumps, capacity ratings can exceed electrical input because of efficiency. Use this calculator for unit conversion, then verify COP or EER separately.

6) Rounding for specifications

Submittals often require consistent significant figures. Use 0–2 decimals for high-level budgeting, and 3–6 decimals for engineering notes or commissioning worksheets. The rounding control lets you match the precision level used on drawings, schedules, and equipment comparison tables.

7) Documentation and traceability

Adding a short context note records where the number came from, such as “generator heat rejection” or “coil capacity.” Exporting CSV supports spreadsheet takeoffs, and the PDF option provides a compact attachment for RFIs, meeting minutes, and procurement packages.

8) Common use cases in construction

Use kW to BTU conversions for temporary heating plans, trailer HVAC selection, process heater checks, generator sizing discussions, and heat rejection estimates near sensitive finishes. Consistent conversions reduce coordination errors across electrical and mechanical scopes on fast-moving projects. For quick field checks, remember 1 kW is about 3.412 kBTU/h. Pair the conversion with airflow, temperature rise, or heat loss estimates to confirm comfort targets during temporary conditioning. This keeps conversations aligned between drawings, field notes, and supplier cut sheets. consistently.

FAQs

1) Is the result BTU or BTU per hour?

By default the calculator reports BTU/h, which is the standard HVAC capacity unit. You can switch to BTU/min, BTU/s, or BTU/day using the output unit selector.

2) Can I use this for heater sizing?

Yes for resistive heaters, where electrical input closely matches heat output. For heat pumps, capacity can be higher than electrical input, so confirm efficiency ratings such as COP, EER, or SEER separately.

3) Why does 3.5 kW show about 11,943 BTU/h?

The calculator multiplies 3.5 by 3412.141633. That gives roughly 11,942.50 BTU/h, which rounds to about 11,943 depending on your selected decimals.

4) What rounding should I choose for submittals?

For schedules and submittals, 0–2 decimals are usually sufficient. For engineering calculations or commissioning logs, use 3–6 decimals to preserve precision across multiple conversions and comparisons.

5) Does this convert cooling tons too?

This tool converts kW to BTU-based rates. If you need tons of cooling, convert BTU/h to tons by dividing by 12,000. Verify whether you are converting capacity or electrical input for the equipment type.

6) Can I use other currencies in the exports?

This calculator does not price items, so currency is not involved. The CSV and PDF exports contain only conversion values and notes for documentation.

7) What if my equipment label is in watts?

Convert watts to kilowatts by dividing by 1000, then enter the kW value. For example, 1500 W equals 1.5 kW, which converts to about 5118 BTU/h.