UseCalcPro
Home
MathFinanceHealthConstructionAutoPetsGardenCraftsFood & BrewingToolsSportsMarineEducationTravel
Blog
  1. Home
  2. Marine

Boat Fuel Calculator

Calculate fuel burn rate and cruising range

Units

Fuel Consumption

13.32

gallons per hour (GPH)

Liters/Hour

50.41

Cost/Hour

$59.94

Cruising Range

Max Range

281.5 nm

11.3 hours

Safe Range (90%)

253.4 nm

10.1 hours

Cost per Nautical Mile$2.40

GPH by Throttle Setting

Trolling / Idle6.1 GPH
Slow Cruise10.2 GPH
Cruise13.3 GPH
Fast Cruise16.4 GPH
Wide Open Throttle20.5 GPH

Typical Fuel Consumption by Boat Type

Boat TypeHP RangeGPH at CruiseRange (nm)
Bass Boat150-2508-1580-120
Center Console200-40012-25100-200
Cabin Cruiser300-60018-40150-300
Pontoon75-1504-850-100
Sailboat (aux)20-501-3200-500

What You'll Need

Star Brite Ultimate Aluminum Cleaner & Restorer 64oz

$18-$254.5
View on Amazon

3M Marine Adhesive Sealant 5200 Fast Cure White 3oz

$14-$204.5
View on Amazon

Shoreline Marine Bilge Pump 600 GPH 12V

$15-$254.3
View on Amazon

Star Brite Ultimate Aluminum Cleaner & Restorer 64oz

$18-$254.5
View on Amazon

3M Marine Adhesive Sealant 5200 Fast Cure White 3oz

$14-$204.5
View on Amazon

Shoreline Marine Bilge Pump 600 GPH 12V

$15-$254.3
View on Amazon

As an Amazon Associate, we earn from qualifying purchases.

Frequently Asked Questions

Q

How do I calculate fuel consumption for my boat?

Fuel consumption in GPH equals engine horsepower multiplied by the load factor and specific fuel consumption, divided by the fuel weight per gallon. For gasoline, SFC is about 0.50 lb/hp/hr and fuel weighs 6.1 lb/gal.

  • Gasoline SFC: 0.50 lb/hp/hr, diesel SFC: 0.40 lb/hp/hr
  • Gasoline weight: 6.1 lb/gal, diesel weight: 7.1 lb/gal
  • A 250 HP gas engine at 65% load burns about 13.3 GPH
  • Diesel engines are 20–30% more fuel efficient than gasoline
  • Actual consumption varies with hull type, weight, and sea conditions
Engine SizeFuel TypeCruise GPHWOT GPH
150 HPGasoline8.012.3
250 HPGasoline13.320.5
150 HPDiesel4.28.5
300 HPDiesel8.516.9
Q

What is a good fuel consumption rate for a boat?

Fuel efficiency varies widely by boat type. Sailboats with auxiliary engines use 1–3 GPH, pontoons 4–8 GPH, center consoles 12–25 GPH, and large cabin cruisers 18–40 GPH at cruise speed.

  • Sailboat auxiliary: 1–3 GPH at 5–7 knots
  • Pontoon boat: 4–8 GPH at 15–20 knots
  • Bass/fishing boat: 8–15 GPH at 25–30 knots
  • Center console: 12–25 GPH at 20–30 knots
  • Cabin cruiser: 18–40 GPH at 15–25 knots
Q

How do I calculate my boat range from fuel capacity?

Divide your tank capacity by GPH to get hours of runtime. Multiply hours by cruise speed in knots for range in nautical miles. Always keep a 10% fuel reserve for safety.

  • Range (hours) = Tank Capacity / GPH
  • Range (nm) = Range (hours) × Cruise Speed (knots)
  • Always reserve 10% of fuel — the "rule of thirds" is even safer
  • 150-gallon tank at 13.3 GPH = 11.3 hours = 282 nm at 25 knots
  • Wind, current, and sea state can reduce range by 15–30%
Q

What is load factor and how does it affect fuel burn?

Load factor is the percentage of maximum engine power being used. Cruising at 65% load is typical. Reducing from 80% to 65% load can cut fuel consumption by about 20% while only reducing speed slightly.

  • Idle/trolling: 30% load — minimum fuel burn, ~2–4 knots
  • Slow cruise: 50% load — best fuel economy for distance
  • Cruise: 65% load — typical comfortable cruising speed
  • Fast cruise: 80% load — near-max speed, significantly higher burn
  • WOT: 100% load — max speed, highest fuel consumption
Q

Is diesel or gasoline more efficient for boats?

Diesel engines are 20–30% more fuel efficient than gasoline engines of similar horsepower. Diesel fuel also contains about 11% more energy per gallon. However, diesel engines cost more upfront and weigh more.

  • Diesel SFC: 0.40 lb/hp/hr vs gasoline SFC: 0.50 lb/hp/hr
  • Diesel fuel: 7.1 lb/gal and 139,000 BTU/gal vs gasoline: 6.1 lb/gal and 125,000 BTU/gal
  • A 250 HP diesel at cruise burns ~9.2 GPH vs ~13.3 GPH for gasoline
  • Diesel engines typically last 5,000–8,000 hours vs 1,500 for gasoline
  • Marine diesel costs $0.50–$1.00 more per gallon than gasoline at marinas

Example Calculations

1250 HP Gasoline Center Console at Cruise

Inputs

Engine HP250
Fuel TypeGasoline
Load Factor65% (Cruise)
Tank Size150 gallons
Cruise Speed25 knots

Result

Fuel Consumption13.32 GPH
Max Range281.5 nm
Range Hours11.3 hours
Safe Range (90%)253.4 nm

GPH = 250 × 0.65 × 0.50 / 6.1 = 13.32. Range = 150 / 13.32 = 11.3 hours. Distance = 11.3 × 25 = 281.5 nm.

2150 HP Diesel Trawler at Slow Cruise

Inputs

Engine HP150
Fuel TypeDiesel
Load Factor50% (Slow Cruise)
Tank Size80 gallons
Cruise Speed8 knots

Result

Fuel Consumption4.23 GPH
Max Range151.3 nm
Range Hours18.9 hours
Safe Range (90%)136.2 nm

GPH = 150 × 0.50 × 0.40 / 7.1 = 4.23. Range = 80 / 4.23 = 18.9 hours. Distance = 18.9 × 8 = 151.3 nm.

Formulas Used

Fuel Consumption (GPH)

GPH = HP × Load Factor × SFC / Fuel Weight

Calculates gallons per hour burned by the engine at a given throttle setting.

Where:

HP= Engine horsepower rating
Load Factor= Throttle percentage (0.30 to 1.00)
SFC= Specific fuel consumption (0.50 for gas, 0.40 for diesel) in lb/hp/hr
Fuel Weight= Weight per gallon (6.1 lb for gas, 7.1 lb for diesel)

Cruising Range

Range (nm) = (Tank Size / GPH) × Speed

Calculates maximum distance in nautical miles before refueling.

Where:

Tank Size= Fuel tank capacity in gallons
GPH= Fuel consumption in gallons per hour
Speed= Cruising speed in knots

Understanding Boat Fuel Consumption

Fuel is the largest recurring cost for powerboat owners. Understanding your engine’s fuel burn rate helps plan trips, budget for fuel stops, and avoid running out of gas offshore. The GPH formula uses engine horsepower, load factor, and fuel-specific constants to estimate real-world consumption.

The load factor represents how hard you’re pushing the engine relative to its maximum output. Most boaters cruise at 60–70% throttle, which balances speed against fuel economy. Small reductions in throttle often yield large fuel savings because drag increases with the cube of speed.

Always plan trips using the "rule of thirds": one-third of fuel to get there, one-third to get back, and one-third in reserve. Marine conditions like headwinds, currents, and rough seas can increase fuel consumption by 15–30% over calm-water estimates.

Related Calculators

Hull Speed Calculator

Theoretical max speed

Nautical Distance Calculator

Great-circle distances

Anchor Chain Calculator

Rode length for anchoring

Gas Mileage Calculator

Vehicle fuel economy

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.

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.

Related Resources

Hull Speed Calculator

Find your hull speed from waterline length

Nautical Distance Calculator

Calculate distance between coordinates

Gas Mileage Calculator

Calculate vehicle fuel efficiency

More Marine Calculators

Explore all marine and boating tools

View All

Last Updated: Mar 25, 2026

This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.

UseCalcPro
FinanceHealthMath

© 2026 UseCalcPro