Maritime & Shipping Calculators

A growing library of free, browser-based calculators for shipbrokers, freight forwarders and vessel operators — covering voyage planning, laytime, freight, stowage, bunker consumption and more. No sign-up, no data logging.

Port-to-Port Sea Distance Calculator

Estimate nautical miles, kilometres and steaming time between major world ports with an adjustable routing margin.

Maritime ETA & Required Speed Calculator

Estimate vessel ETA from distance and speed, or compute the speed needed to meet a target arrival.

Freight CBM & Chargeable Weight Calculator

Calculate CBM, gross weight, and sea/air freight chargeable weight across multiple package types with cm/inch and kg/lb toggles.

Marine Fuel (Bunker) Consumption & CO2 Estimator

Estimate total voyage bunker consumption and CO₂ emissions using official IMO carbon factors for HFO, LFO, MGO and LNG.

Shipping Container TEU to FEU Converter

Convert between 20ft (TEU) and 40ft (FEU) containers and estimate total CBM and max payload for mixed fleets.

Vessel Laytime & Demurrage Calculator

Preview laytime, demurrage and despatch amounts from allowed vs actual time used and agreed daily rates.

Shipping Container Door Clearance Checker

Check whether cargo will pass through a 20ft, 40ft or High Cube container door using standard ISO door dimensions.

Marine Stowage Factor & Cargo Volume Fit Calculator

Check whether dry bulk or breakbulk cargo will fit in a vessel hold using stowage factor, hold volume and broken stowage allowance.

Maritime Distance-Speed-Time (DST) Matrix Calculator

Compare 3 vessel speed scenarios side-by-side — steaming time, ETA, and hours saved or lost vs standard speed — from a single voyage distance and departure time.

Freight Conversion Multi-Tool (All-in-One Shipping Converter)

Convert cargo weights (MT/LT/ST), marine bunker volumes (MT/Liters/US Gallons/Barrels), and nautical depth units (meters/feet/fathoms) in one tool.

Vessel IMO Number Check Digit Validator

Instantly validate a 7-digit vessel IMO number using the standard SOLAS check-digit formula, with a full mathematical breakdown.