Category · General · 5 converters

Field unit converters for the dual-system job site

US equipment arrives in AWG, CFM, HP, and BTU/hr. Codes and metric specs speak mm², L/s, kW, and tons. Each converter below bridges the gap — with the cable to order, the code table behind the number, and a direct link into the calculator that uses the result. No signup. Works offline.

Last updated: October 2026

AWG ↔ mm² ↔ kcmil

Wire gauge to metric with the IEC cable size to order, DC resistance, and NEC 310.16 ampacity reference.

ASTM B258 · IEC 60228

Open converter →

CFM ↔ L/s ↔ m³/h

Airflow with ACH from room size, CFM/ton, and fixture badges for bath fans, hoods, and furnaces.

1 CFM = 0.4719 L/s

Open converter →

kW ↔ BTU/hr ↔ Tons

Thermal power with MBH, EER/COP bridge, boiler input-vs-output, and equipment context.

1 kW = 3,412 BTU/hr

Open converter →

HP ↔ kW (motors)

Shaft power with NEC Table 430.250 FLA, 125% conductor minimum, and 250% breaker maximum.

NEC 430 · 1 HP = 0.7457 kW

Open converter →

°F ↔ °C + ΔT

HVAC design-temperature presets plus a delta-T calculator for Manual D and derating math.

°C = (°F − 32) × 5/9

Open converter →

More on the way

Pressure (psi ↔ bar ↔ Pa), length (ft ↔ m), and velocity (FPM ↔ m/s) converters are next. Tell us what you need via the contact page.

Roadmap

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Why these five

The conversions the job site actually needs

Every converter on this page exists because a FieldCalc calculator needs its output. Wire specs in AWG feed the wire-size calculator (NEC 310.16); ventilation rates in L/s feed the duct-sizing calculator (Manual D); motor HP feeds conductor sizing per NEC 430; equipment tons feed both load and airflow math. Convert here, then carry the number straight into the tool — many pages pre-fill the calculator for you.

Each converter shows more than the converted number: the metric cable size you actually order (never the raw conversion), the NEC or IEC table behind the result, and the field trap to avoid (input vs output kW, shaft vs electrical HP, diameter vs area). That context is what separates a unit converter from a field tool.

FAQ

Converter questions, answered

Which converter do I need?

Wire specs → AWG to mm². Ventilation rates → CFM to L/s. Equipment capacity → kW to BTU/hr. Motor nameplates → HP to kW. Temperatures → °F to °C. Each page links into the calculator that uses its result.

Where do the conversion factors come from?

NIST SP 811 (HP, BTU), ASTM B258 (AWG dimensions), IEC 60228 (metric cable), NEC 2023 Tables 310.16 and 430.250 (ampacity, FLA), ASHRAE 62.1/62.2 (ventilation). Every converter names its standard.

Do these converters work offline?

Yes. FieldCalc is an installable PWA — after your first visit, every converter runs with zero signal, including in basements and mechanical rooms. All math stays on your device.

Are these converters really free?

Yes — every converter, every page, no account, no locked features. Calculations run client-side, so your inputs never leave your device.