Linear Range and Scale Converter
Set two ranges and edit either value for bidirectional linear scaling. Use it for numerical mappings such as 4–20 mA to engineering units, or 0–10 V to percent.
Inputs and reverse calculation
Calculated results
| Range 1 value | 5 |
|---|---|
| Range 2 value | 15 |
How to interpret the result
Two endpoints define a linear scale. Calculate the position within one range and apply the same fraction to the other range; either side can drive the calculation.
Formulas and units
v2 = min2 + (v1−min1)(max2−min2)/(max1−min1); swap 1 and 2 for the inverse. Sliders use 100 ticks per unit, giving a 0.01 step.
Worked example
Mapping 4–20 to 0–100 gives 50 for an input of 12; editing the second value to 75 gives 16. If the first range is mA and the second is percent, this means 12 mA ↔ 50%.
Scope and limitations
Both maxima must exceed their minima. Extrapolation and reversed endpoints are unsupported. Out-of-range changes are rejected rather than silently clamped as in the App. Endpoint changes use range 1 unless the immediately preceding edit was the range 2 value or slider. Sliders use 0.01 steps; typed inputs may be finer. This is numerical scaling, not a model of sensor errors, wire-break diagnostics or loop power.
Common questions
Should a 4–20 mA scale use 0.004–0.020?
Both ranges contain unitless numbers. If a range is defined in mA, enter 4, 20 and a value expressed in mA. Do not mix A and mA within one range.
Why are out-of-range values not automatically clamped?
Automatic clamping can hide sensor overrange or an endpoint error. This tool shows the error and preserves the last valid result so the input can be corrected.
Related tools
Formula and data sources
Rebuilt from the extracted Electrodoc Pro 5.2 specification. Added, inferred and corrected behavior is identified in the limitations. Updated 2026-11-13.