Helmwright Nautical Calculator

Helmwright is a navigation calculator for sailors, skippers, delivery crews and navigation students. It works like a hardware calculator: a sea-green chassis, real keys and a clear LCD, with each answer labelled so you know what you are reading.

SPEED, TIME AND DISTANCE
• Any two of speed, time and distance give the third, in knots and nautical miles
• ETA from a departure time
• Hull speed and speed-length ratio from waterline length

CURRENT
• Course to steer and speed made good against a known set and drift
• Course and speed made good from course, speed and current
• Set and drift from your dead-reckoning position and a fix

COMPASS
• True to compass and back: variation and deviation, east or west

HORIZON AND LIGHTS
• Distance to the horizon from height of eye
• Geographic range of a light
• Distance off by vertical sextant angle

TIDES AND FUEL
• Height of tide by the rule of twelfths, for any range and duration
• Endurance, range and fuel for a trip from burn rate

WORKS THE WAY YOU DO
• Feet or metres for heights, gallons or litres for fuel
• A results strip shows every solved value at once
• 10 memories, a tape of your calculations, reference tables and a key guide
• Export a job strip: the tape with inputs, stamped and ready to attach to a passage plan or logbook, as text or PDF

TRY PRO FREE FOR 7 DAYS
Try every feature free for 7 days, then keep Pro with a yearly subscription. Cancel anytime in Google Play. No ads, works offline.

PRIVATE BY DESIGN
Works offline, no account, no data collected.

How it's calculated: the formulas and tables behind every result, at https://wrightcalc.app/helmwright/

Questions or feedback: [email protected]

For passage planning and training. Not a substitute for official charts, tide tables, notices to mariners or proper watchkeeping. Verify every result. The developer accepts no liability for loss or damage arising from use.