What is a heat transfer coefficient?

The heat transfer coefficient h (W/m²·K) describes how efficiently heat flows between a surface and a fluid per unit area and temperature difference: Q = h × A × ΔT.

What are typical h-values for convection?

Natural (still) air: 5–25 W/m²·K; forced air: 25–250; forced water: 500–10 000; boiling water: 2 500–25 000; condensing steam: 5 000–50 000 W/m²·K.

How do I convert BTU/(hr·ft²·°F) to W/(m²·K)?

Multiply by 5.6783. For example, 10 BTU/(hr·ft²·°F) = 56.783 W/(m²·K).

Is this tool private and browser-based?

Yes - all conversions run client-side in JavaScript.

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Heat Transfer Converter

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From

Sig. figures:

Sci notation

Watt per m²·K

W/(m²·K)

1(input)

Watt per m²·°C

W/(m²·°C)

Kilowatt per m²·K

kW/(m²·K)

0.001

Watt per cm²·K

W/(cm²·K)

0.0001

Milliwatt per cm²·K

mW/(cm²·K)

0.1

Watt per ft²·K

W/(ft²·K)

0.092903

BTU per hr·ft²·°F

BTU/(hr·ft²·°F)

0.17611

BTU per min·ft²·°F

BTU/(min·ft²·°F)

0.00293517

BTU per sec·ft²·°F

BTU/(s·ft²·°F)

4.89195e-5

Calorie per s·cm²·°C

cal/(s·cm²·°C)

2.38846e-5

Calorie per hr·cm²·°C

cal/(hr·cm²·°C)

0.0859845

Kilocalorie per hr·m²·°C

kcal/(hr·m²·°C)

0.859845

Hover any row to copy or use as input.

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Convert between all common heat transfer coefficient units across three groups: SI (W/m²·K, W/m²·°C, kW/m²·K, W/cm²·K, mW/cm²·K, W/ft²·K), Imperial/BTU (BTU/hr·ft²·°F, BTU/min·ft²·°F, BTU/s·ft²·°F), and Caloric (cal/s·cm²·°C, cal/hr·cm²·°C, kcal/hr·m²·°C). Includes typical h-values for natural convection, forced convection, boiling water, condensing steam, windows, and insulated walls. Adjustable precision, sci notation, swap units, copy any row.

How to Use

1Enter a heat transfer coefficient value in the From field
2Choose the source unit from SI, Imperial, or Caloric groups
3Select the target unit in the To dropdown to see the instant result
4Browse all unit groups in the results panel - collapse any group to save space
5Open the Reference panel for typical h-values in HVAC and process engineering
6Hover any row to copy the value or use it as the new input

Features

SI group: W/m²·K, W/m²·°C, kW/m²·K, W/cm²·K, mW/cm²·K, W/ft²·K
Imperial group: BTU/hr·ft²·°F, BTU/min·ft²·°F, BTU/s·ft²·°F
Caloric group: cal/s·cm²·°C, cal/hr·cm²·°C, kcal/hr·m²·°C
Instant two-way conversion with From/To selectors and swap button
3–12 significant figures and scientific notation toggle
Reference panel with typical h-values for air, water, boiling, condensing steam
100% browser-based - all calculations in JavaScript

Heat Transfer Converter

How to Use

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