Pressure Calculator
Pressure is defined as force per unit area: P = F/A. The SI unit is the Pascal (Pa = N/m²), but engineering practice uses many other units — psi (pounds per square inch) in the US, bar and kPa in Europe, atm for atmospheric reference. Fluid (hydrostatic) pressure increases linearly with depth: P = ρgh, where ρ is fluid density, g is gravitational acceleration, and h is depth. Every 10 m of water depth adds approximately 1 atm (101.325 kPa) of pressure. Understanding pressure is essential for hydraulics, pneumatics, HVAC, diving, weather forecasting, and chemical engineering.
compress P = F / A
Tip: 1 cm² = 0.0001 m²
analytics Results
Pressure
—
Formula used
—
Enter values to calculate
water P = ρgh
analytics Results
Gauge Pressure
—
Formula
—
Enter depth to calculate
swap_vert Gauge ↔ Absolute
Default: 101325 Pa (1 atm at sea level)
analytics Results
Result
—
Formula
—
—
Enter pressure to convert
swap_horiz Pressure Unit Converter
analytics Conversions
Enter a pressure to convert
lightbulb Tips
- •P = F/A — Pressure = Force ÷ Area (SI unit: Pascal)
- •Fluid depth: P = ρgh (1 atm per 10.33 m of water)
- •1 atm = 101,325 Pa = 14.696 psi = 1.01325 bar
- •Gauge pressure = absolute − atmospheric
How to Use This Calculator
Choose a Calculation Mode
Select Force/Area (P = F/A) to calculate pressure from a force, Fluid Depth (P = ρgh) for hydrostatic pressure, Gauge/Absolute to convert between reference types, or Unit Converter to switch between psi, bar, kPa, and other units.
Enter the Known Values
Fill in the values you know. For force/area enter force in Newtons and area in m². For depth enter fluid density and depth. For unit conversion just type any pressure value and select the source unit.
Read Results in Multiple Units
Results appear instantly in Pa, kPa, MPa, bar, psi, atm, and mmHg simultaneously so you can use the most convenient unit for your application.
Apply to Your Project
Use the formula shown below the result to verify the calculation. Check the Quick Reference panel on the right for common pressure values and unit conversion factors.
The Formula
Pressure (P = F/A) measures how concentrated a force is over a surface. 1 Pascal = 1 Newton per square meter — roughly the pressure of a dollar bill lying flat. Standard atmospheric pressure is 101,325 Pa = 1 atm = 14.696 psi = 1.01325 bar. In fluids, pressure increases with depth: every 10.33 m of water adds 1 atm. Gauge pressure is measured relative to atmosphere; absolute pressure includes atmospheric pressure. Most pressure gauges read gauge pressure.
P = F/A | P = ρgh | P_abs = P_gauge + P_atm
lightbulb Variables Explained
- P Pressure in Pascals (Pa = N/m²)
- F Force applied in Newtons (N)
- A Area over which force is applied (m²)
- ρ Fluid density (kg/m³) — water ≈ 1000 kg/m³
- g Gravitational acceleration = 9.80665 m/s²
- h Depth or height of fluid column (m)
- P_abs Absolute pressure (gauge + atmospheric)
tips_and_updates Pro Tips
1 bar ≈ 1 atm (atmosphere). More precisely: 1 atm = 1.01325 bar = 101,325 Pa = 14.696 psi.
Tire pressure gauges read gauge pressure. A tire showing 32 psi has absolute pressure of 32 + 14.7 = 46.7 psi.
Water pressure increases by 0.433 psi (2.99 kPa) per foot of depth, or 1 atm per 33.9 ft (10.33 m).
Blood pressure (120/80 mmHg) is gauge pressure — the 120 mmHg systolic is measured above atmospheric.
Vacuum pressure is negative gauge pressure. A perfect vacuum = −101.325 kPa gauge = 0 Pa absolute.
Frequently Asked Questions
Related Tools
View all Engineering View all arrow_forwardTags
Data sourced from trusted institutions
All formulas verified against official standards.