Calculate pressure to current for 4–20 mA transmitters using LRV, URV, pressure, or current values, plus I/P pneumatic pressure scaling.

Ideal linear scaling, not a device calibration. All pressure inputs must use the same absolute/gauge reference. Out-of-span results are extrapolations; actual devices may saturate or signal a fault.

Related Calculators

Pressure to Current Formula

The following formula is used to calculate the current for a given pressure, or vice versa.

I = ((P - Pₘᵢₙ) / (Pₘₐₓ - Pₘᵢₙ)) × (Iₘₐₓ - Iₘᵢₙ) + Iₘᵢₙ

Variables:

  • P is the pressure
  • Pmin is the minimum pressure
  • Pmax is the maximum pressure
  • Imin is the minimum current
  • Imax is the maximum current
  • I is the current

To calculate the current, subtract the minimum pressure from the given pressure, divide by the difference between the maximum and minimum pressure, then multiply by the difference between the maximum and minimum current, and finally add the minimum current.

Legacy Custom-Scale Table (assumed k = 10 A per psi)
Pressure (psi) Current (A)
0.55
110
220
330
550
7.575
10100
12120
15150
20200
25250
30300
40400
50500
60600
75750
1001000
1501500
2002000
3003000
*This table uses the legacy custom assumption I (A) = 10 × P (psi), not a universal conversion or 4–20 mA transmitter scale. Pressure is in psi; current is in A.

What is Pressure to Current Conversion?

Pressure to current conversion is a process used in various industrial applications to convert a pressure measurement into a corresponding electrical current signal. This is often done using transducers or transmitters that output a current proportional to the pressure. This conversion is crucial for monitoring and controlling processes in industries such as oil and gas, chemical manufacturing, and water treatment.

How to Calculate Pressure to Current?

The following steps outline how to calculate the current from pressure or vice versa.

  1. First, determine the pressure (P).
  2. Next, determine the minimum pressure (Pmin).
  3. Next, determine the maximum pressure (Pmax).
  4. Next, determine the minimum current (Imin).
  5. Next, determine the maximum current (Imax).
  6. Finally, calculate the current (I) using the formula provided above.
  7. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Pressure (P) = 50 psi

Minimum Pressure (Pmin) = 20 psi

Maximum Pressure (Pmax) = 100 psi

Minimum Current (Imin) = 4 mA

Maximum Current (Imax) = 20 mA. I = ((50 − 20) / (100 − 20)) × (20 − 4) + 4 = 10 mA.