Conversion method
Heat-flow rate per area. This is not total heat energy or a temperature-normalized heat-transfer coefficient.
kW/m² = x × 0.001
10 W/m² = 0.01 kW/m².
| W/m² | kW/m² |
|---|---|
| 1 | 0.001 |
| 5 | 0.005 |
| 10 | 0.01 |
| 25 | 0.025 |
| 50 | 0.05 |
| 100 | 0.1 |
Unit definitions and sources
Heat-flow rate per area. This is not total heat energy or a temperature-normalized heat-transfer coefficient.
| Unit and system | Use | Definition | Relationship |
|---|---|---|---|
| Watt per square meter (W/m²); si | Common units | Watt per square meter: base (w-m2) = value × 1. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Kilowatt per square meter (kW/m²); si | Common units | Kilowatt per square meter: base (w-m2) = value × 1000. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Watt per square centimeter (W/cm²); si | Specialist units | Watt per square centimeter: base (w-m2) = value × 10000.0. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| BTU (IT) per hour square foot (BTU IT/(h·ft²)); si | Specialist units | BTU (IT) per hour square foot: base (w-m2) = value × 3.1545907450630484. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Watt/square inch (W/(in²)); other | Specialist units | watt/square inch = 1550.0031000062002 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Joule/second/square meter (J/(s)/(m²)); other | Specialist units | joule/second/square meter = 1.0 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Kilocalorie (IT)/hour/square meter (kcal IT/(h)/(m²)); other | Specialist units | kilocalorie (IT)/hour/square meter = 1.163 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Kilocalorie (IT)/hour/square foot (kcal IT/(h)/(ft²)); other | Specialist units | kilocalorie (IT)/hour/square foot = 12.518427814633407 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Calorie (IT)/second/square centimeter (cal IT/(s)/(cm²)); other | Specialist units | calorie (IT)/second/square centimeter = 41868.0 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Calorie (IT)/minute/square centimeter (cal IT/(min)/(cm²)); other | Specialist units | calorie (IT)/minute/square centimeter = 697.8 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Calorie (IT)/hour/square centimeter (cal IT/(h)/(cm²)); other | Specialist units | calorie (IT)/hour/square centimeter = 11.629999999999999 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Calorie (th)/second/square centimeter (cal th/(s)/(cm²)); other | Specialist units | calorie (th)/second/square centimeter = 41840.0 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Calorie (th)/minute/square centimeter (cal th/(min)/(cm²)); other | Specialist units | calorie (th)/minute/square centimeter = 697.3333333333334 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Calorie (th)/hour/square centimeter (cal th/(h)/(cm²)); other | Specialist units | calorie (th)/hour/square centimeter = 11.622222222222222 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Dyne/hour/centimeter (dyn/(h)/(cm)); other | Specialist units | dyne/hour/centimeter = 2.777777777777778e-07 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Btu (IT)/second/square foot (BTU IT/(s)/(ft²)); other | Specialist units | Btu (IT)/second/square foot = 11356.526682226975 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Btu (IT)/minute/square foot (BTU IT/(min)/(ft²)); other | Specialist units | Btu (IT)/minute/square foot = 189.2754447037829 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Btu (th)/second/square inch (BTU th/(s)/(in²)); other | Specialist units | Btu (th)/second/square inch = 1634246.1784501346 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Btu (th)/second/square foot (BTU th/(s)/(ft²)); other | Specialist units | Btu (th)/second/square foot = 11348.931794792601 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Btu (th)/minute/square foot (BTU th/(min)/(ft²)); other | Specialist units | Btu (th)/minute/square foot = 189.14886324654333 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
| Btu (th)/hour/square foot (BTU th/(h)/(ft²)); other | Specialist units | Btu (th)/hour/square foot = 3.1524810541090558 w-m2, derived from the component SI/customary definitions. Common use: Heat Flux Density. Source checked 2026-09-20 (implementation review). | Exact definition; numerical display may be rounded |
Sources: NIST: SP 811 Appendix B.8: conversion factors; BIPM: SI prefixes
Precision of heat flux density conversions
All 21 heat flux density units convert through Watt per square meter (W/m²). 21 have an exact defined relationship to the base unit and 0 are conventional or measured values. Results and the tables on this page come from the same engine, so a table value can be checked against the converter directly.
Standard display shows up to six decimal places, switching to scientific notation for very large or small values. Calculation uses JavaScript binary floating point independently of display rounding, so extra digits are not a claim about measurement accuracy. Each unit lists its own source; a citation records where the definition comes from, not an independent review. See Conversion methodology for the review and correction process.