Marine Calculators
Boating, sailing, fishing and marine systems
25 calculators in this category
Boat Fuel Calculator
Calculate your boat's fuel consumption in gallons per hour from engine horsepower and load. Estimate cruising range from tank capacity and fuel burn rate.
Hull Speed Calculator
Calculate your boat's theoretical hull speed from waterline length. Find the speed-to-length ratio and understand wave resistance limits for displacement hulls.
Anchor Chain Calculator
Calculate the required anchor rode length from water depth, tide range, and weather conditions. Get scope ratios and chain-to-rope mix for safe anchoring.
Sail Area Calculator
Calculate your sailboat's total sail area from mainsail and jib dimensions. Find the SA/displacement ratio to classify performance from cruiser to racer.
Nautical Distance Calculator
Calculate the great-circle distance in nautical miles between two coordinates using the Haversine formula. Plan ocean passages with accurate route distances.
Tidal Current Calculator
Estimate tidal current speed and direction using the rule of twelfths from high and low tide data. Plan safe harbor entries and optimal passage timing.
Boat Displacement Calculator
Calculate boat displacement from hull dimensions using Simpson's rule. Find the displacement-to-length ratio to classify your vessel from ultralight to heavy.
Compass Deviation Calculator
Convert between true, magnetic, and compass headings with variation and deviation corrections. Use the TVMDC formula for accurate marine navigation bearings.
Boat Speed Calculator
Calculate boat speed over ground, speed through water, and velocity made good to windward. Determine current set and drift from GPS and log speed differences.
Propeller Sizing Calculator
Size your boat propeller by calculating optimal diameter and pitch from engine horsepower, RPM, and gear ratio. Analyze slip percentage for peak efficiency.
Ballast Ratio Calculator
Calculate your sailboat's ballast-to-displacement ratio and capsize screening value. Assess stability with righting moments at different heel angles for safety.
Navigation ETA Calculator
Calculate your estimated time of arrival from distance, boat speed, and current conditions. Plan multi-waypoint passages with fuel stops and tidal gate windows.
Water Depth Sonar Calculator
Calculate water depth from sonar ping time using speed of sound in water. Adjust for temperature and salinity effects on acoustic velocity for accurate depths.
Fishing Hook Size Calculator
Find the right fishing hook size for your target species and bait type. Convert between aught and numeric sizing systems with our hook gap ratio calculator.
Fishing Weight Calculator
Calculate the right sinker weight for your fishing conditions. Factor in current speed, water depth, and line diameter to keep your bait in the strike zone.
Trolling Speed Calculator
Calculate optimal trolling speed and lure running depth from line length and lure weight. Use catenary curve physics to dial in your presentation perfectly.
Fish Pond Stocking Calculator
Calculate how many fish to stock in your pond based on surface area and carrying capacity. Get species mix ratios for bass, bluegill, catfish, and trout ponds.
Boat Paint Calculator
Calculate how much bottom paint you need from hull dimensions. Estimate wetted surface area, gallons per coat, and total cost for antifouling your boat hull.
Boat Winterization Calculator
Calculate antifreeze volumes for engine, water systems, and tanks for boat winterization. Estimate shrink wrap material and total winter storage costs.
Marine Battery Calculator
Size your marine battery bank from electrical loads and daily usage. Calculate amp-hours needed, number of batteries, and charging time for reliable boat power.
Bilge Pump Calculator
Size your bilge pump from boat length and worst-case breach scenarios. Calculate required GPH flow rate with head loss for discharge height above the waterline.
Dock Line Calculator
Calculate the right dock line diameter and length for your boat's displacement. Size bow, stern, breast, and spring lines with working load safety margins.
Marine Engine Hours Calculator
Estimate your marine engine's remaining life from current hours and usage patterns. Calculate true cost per hour including fuel, maintenance, and depreciation.
Boat Trailer Weight Calculator
Calculate your total boat trailer towing weight including boat, motor, fuel, and gear. Check tongue weight percentage and match against your tow vehicle rating.
Marine Holding Tank Calculator
Calculate your boat's holding tank capacity needs from crew size and trip duration. Plan pump-out schedules and estimate days of use before reaching capacity.