what is the pressure on a swimmer 10m below

June 28, 2026

The pressure on a swimmer 10 m below the surface of a lake is about 2.0×1052.0\times 10^52.0×105 pascal (Pa), i.e., roughly 2 atmospheres total pressure.

Quick Scoop

Depth below surface: 10 m in (fresh) water
Water density ρ≈1000 kg/m3\rho \approx 1000,\text{kg/m}^3ρ≈1000kg/m3
g≈10 m/s2g\approx 10,\text{m/s}^2g≈10m/s2
Atmospheric pressure at the surface P0≈1.01×105 PaP_0\approx 1.01\times 10^5,\text{Pa}P0≈1.01×105Pa

Hydrostatic pressure due to water column:

Pwater=ρgh=1000×10×10=1.0×105 PaP_{\text{water}}=\rho gh=1000\times 10\times 10=1.0\times 10^5,\text{Pa}Pwater=ρgh=1000×10×10=1.0×105Pa

This matches worked examples for 10 m water depth.

Total (absolute) pressure on the swimmer:

P=P0+ρgh≈1.01×105+1.0×105≈2.01×105 PaP=P_0+\rho gh\approx 1.01\times 10^5+1.0\times 10^5\approx 2.01\times 10^5,\text{Pa}P=P0+ρgh≈1.01×105+1.0×105≈2.01×105Pa

In more intuitive terms, pressure increases by about 1 atmosphere every 10 m of depth in water, so at 10 m you feel about 2 atmospheres: 1 from the air plus 1 from the water above you.

HTML table version

html

<table>
  <tr>
    <th>Quantity</th>
    <th>Value</th>
  </tr>
  <tr>
    <td>Depth below surface</td>
    <td>10 m</td>
  </tr>
  <tr>
    <td>Water density (ρ)</td>
    <td>1000 kg/m³</td>
  </tr>
  <tr>
    <td>g (gravity)</td>
    <td>10 m/s²</td>
  </tr>
  <tr>
    <td>Pressure from water (ρgh)</td>
    <td>1.0 × 10⁵ Pa</td>
  </tr>
  <tr>
    <td>Atmospheric pressure (P₀)</td>
    <td>1.01 × 10⁵ Pa</td>
  </tr>
  <tr>
    <td>Total pressure at 10 m</td>
    <td>≈ 2.01 × 10⁵ Pa (about 2 atm)</td>
  </tr>
</table>