Pressure Calculator
Use P = F ÷ A to find pressure from force and area, the force produced by a pressure on an area, or the area needed. Mix units freely, use a circle diameter for pistons and pipes, and see the result in every common pressure unit.
How to use the Pressure Calculator
- Choose what to solve for: pressure, force or area.
- Enter the known values and pick their units.
- For pistons or pipes, choose “Circle diameter” and enter the bore.
- Read the result and its conversions to other units.
- Check the steps and the full unit table.
Pressure, force and area formulas
| Solve for | Formula | Example |
|---|---|---|
| Pressure | P = F ÷ A | 1,000 N ÷ 0.001 m² = 1,000,000 Pa (1 MPa) |
| Force | F = P × A | 200 kPa × 0.05 m² = 10,000 N |
| Area | A = F ÷ P | 5,000 N ÷ 200,000 Pa = 0.025 m² |
| Circle area | A = π × d² ÷ 4 | d = 50 mm → 1,963.5 mm² |
Pressure unit conversions
| Unit | Pascals (Pa) | psi | bar |
|---|---|---|---|
| 1 Pa | 1 | 0.000145038 | 0.00001 |
| 1 kPa | 1,000 | 0.145038 | 0.01 |
| 1 psi | 6,894.757 | 1 | 0.0689476 |
| 1 bar | 100,000 | 14.5038 | 1 |
| 1 atm | 101,325 | 14.6959 | 1.01325 |
| 1 mmHg (torr) | 133.322 | 0.0193368 | 0.00133322 |
| 1 MPa (N/mm²) | 1,000,000 | 145.038 | 10 |
| 1 kgf/cm² | 98,066.5 | 14.2233 | 0.980665 |
Force units: 1 lbf = 4.44822 N and 1 kgf = 9.80665 N. Area units: 1 in² = 6.4516 cm² and 1 ft² = 0.092903 m².
Frequently asked questions
What is the pressure formula?
Pressure is force divided by the area it acts on: P = F ÷ A. In SI units, 1 newton on 1 square metre is 1 pascal (Pa). Rearranged, force is F = P × A and area is A = F ÷ P.
How do I calculate the force of a hydraulic cylinder?
Multiply the pressure by the piston area: F = P × π × d² ÷ 4. A 2-inch bore has an area of 3.1416 in², so at 3,000 psi it pushes with about 9,425 lbf (41.9 kN), before friction losses.
How many pascals are in a psi or a bar?
1 psi = 6,894.757 Pa, 1 bar = 100,000 Pa = 14.5038 psi, and 1 standard atmosphere = 101,325 Pa = 1.01325 bar = 14.696 psi. 1 MPa equals 1 N/mm².
Why do sharp knives cut better?
The same force on a much smaller area gives a much higher pressure. 50 N on a blade edge of 0.5 mm² is 100 MPa, while the same force on a fingertip of 1 cm² is only 0.5 MPa.
Is kgf a correct unit of force?
Kilogram-force (kgf) is the weight of 1 kg under standard gravity: 1 kgf = 9.80665 N. It is not an SI unit, but it is still common on scales and in engineering, for example kgf/cm² (≈ 0.98 bar).
What is the difference between gauge and absolute pressure?
Gauge pressure (psig, barg) is measured relative to the surrounding air, so a flat tire reads 0. Absolute pressure adds atmospheric pressure, about 101.3 kPa or 14.7 psi at sea level. P = F ÷ A gives the pressure difference produced by the force.