Weldon MarineBoating calculators
Notice to marinersPreview: the Helm Pass is $1.95 a month or $19.50 a year and is free during preview. Nothing is charged. Pricing

Calculator 1 of 4 · free

Fuel and range

How far the tank takes you, and how far out you can go under the one-third rule: one third of the fuel to go out, one third to get back, one third held in reserve.

Tip: a free Boat Card remembers your boat's numbers and fills these in.

What you can actually burn, not the tank's nameplate size.
Your engine maker's figure, or measure it on the Boat Card.
Clear

Fill in usable fuel, burn and speed. Example: 60 gallons, 6 gal/h, 24 knots, 70 nautical miles out.

Source for the rule: U.S. Coast Guard, A Boater's Guide to the Federal Requirements for Recreational Boats, "Fuel Management" (PDF page 43): one-third of the fuel to go out, one-third to get back, one-third held in reserve.

Get help when the numbers surprise you: if your measured burn jumps or the boat will not reach its usual speed, have a marine mechanic look before a long run. New to planning trips? A boating safety course covers fuel planning in full.

Helm Pass $1.95 a month or $19.50 a year · Free during preview · what it buys

With the Helm Pass, the Boat Card keeps up to 1,000 fill-ups per boat, works out the burn from all of them, and prints a Helm Card for your boat with its one-third rule figures, a "turn back by" table and an anchor line table.