Verification: factors follow standard unit definitions; round for display only.

Feet per second to knots

Convert ft/s to knots when US ballistics tables, HVAC face-velocity specs, or piping schedules quote feet per second but a METAR, marine GPS, or aviation brief expects nautical miles per hour.

Feet per second (ft/s) and knots (kn) both express speed, but they use different length units—international feet versus nautical miles. This site converts through the shared SI anchor (Meter per second = 1):

Foot per second = 0.3048 m/s  ·  Knot = 0.514444 m/s  ·  knots = ft/s × 0.5924843132

At catalog precision, 1 ft/s = 0.592484 knots. A knot represents a slightly larger distance per hour than the same numeric ft/s would suggest when compared to statute miles—but here both units are converted exactly through meters per second.

Step-by-step conversion (worked example — 10 ft/s stream flow)

Convert 10 ft/s from an open-channel hydraulics report:

1. Write the formula: knots = ft/s × 0.5924843132
2. Multiply: 10 × 0.5924843131613937 = 5.925 knots
3. Round for display: 5.9 knots on a marine chart overlay

Second worked example (50 ft/s industrial duct)

A high-velocity duct test lists 50 ft/s:

1. 50 × 0.5924843131613937 = 29.62 knots
2. Context: compare to small-craft wind advisories often quoted in knots

Third worked example (1 ft/s anchor)

Convert exactly 1 ft/s:

1. 1 × 0.5924843131613937 = 0.592484 knots
2. Reverse check: 0.592484 × 1.687808 ≈ 1 ft/s ✓

Quick mental estimate (no calculator)

Multiply ft/s by 0.59 for a close knot estimate (~0.4% low). Example: 20 ft/s → 11.8 knots (exact: 11.85 knots). Reverse: multiply knots by 1.69 for ft/s.

Feet per second to knots conversion chart

Where ft/s → knots comes up

• Marine & aviation crossover: River current in ft/s from US hydrology reports compared against harbor wind or vessel speed in knots.
• HVAC & piping: US face-velocity specs in ft/s translated for offshore platform ventilation rated in knots-equivalent wind loads.
• Ballistics & safety: Muzzle or fragment speeds in ft/s checked against METAR wind in knots for range safety briefings.
• Unit normalization: Mixed US engineering and international marine data merged into one SI-backed spreadsheet column.

Knots to feet per second

Convert knots to ft/s when a METAR, marine GPS, or aviation brief lists nautical miles per hour but US ballistics, HVAC, or piping schedules expect feet per second.

Invert ft/s-to-knots by multiplying knots by 1.6878083990 (catalog ratio 0.514444 ÷ 0.3048):

ft/s = knots × 1.6878083990  ·  equivalently   ft/s = knots ÷ 0.5924843132

Step-by-step conversion (worked example — 30 knots)

Convert 30 knots, a common small-craft wind band:

1. Multiply: 30 × 1.6878083989501311 = 50.63 ft/s
2. Context: about 34.5 mph equivalent—typical small-craft advisory wind band

Second worked example (15 knots)

Convert 15 knots for a coastal engineering check:

1. 15 × 1.6878083989501311 = 25.32 ft/s

Quick reference (knots → ft/s)

See the dedicated knots to ft/s page for extended marine and aviation context.

Ft/s vs knots, common mistakes, and related tools

Feet per second and knots are not numerically equal. Use catalog m/s anchors and verify with round-trip pairs.

Feet per second vs knots at a glance

Common mistakes to avoid

• Assuming 1 ft/s = 1 knot—one knot is about 1.69 ft/s, not 1 ft/s.
• Confusing knots with mph—statute mph and knots use different mile definitions; use dedicated converters for mph comparisons.
• Mixing ft/min with ft/s—divide ft/min by 60 before converting to knots.
• Rounding catalog ratios too early—use full 0.3048 and 0.514444 precision in spreadsheets; round only the final displayed value.

Exactness and round-trip verification

Both catalog factors derive from defined length units converted to m/s. Converting 10 ft/s → 5.9248 kn → 10 ft/s should recover the original within floating-point limits.

Related speed converters

See knots to ft/s, ft/s to m/s, knots to m/s, mph to knots, and ft/s to mph.