Devon Gamba
Founder
05 · Shipping calculators
DockMath
Know what fits, and what it costs.
DockMath is a set of free calculators for US importers and exporters, in English and Spanish: what fits in a container, what the shipment costs, and what the carrier charges if a container sits at the port too long.
A shipping container you can turn, packed with cartons the way DockMath plans a load. Pick a container and a carton size to see how many fit.
The story
The story
Shipping math is spread all over the place. Carriers publish their free time and charges in their own PDFs and price lists, port by port, and each one counts the days a little differently.
DockMath puts it in one place. It does the math the way carriers, forwarders and customs actually bill, and every figure from an outside source links to that source and shows when it was last checked.
How it works
How it works
Plan the load
See how many cartons or pallets fit in each container size, with a 3D picture of the load, plus CBM and TEU.
Price the shipment
Check ocean freight rates, chargeable weight and freight class, and add up the landed cost with duties and fees.
Check the port terms
Pick a carrier and a port to load its free time and daily charges straight into the demurrage and detention calculator.
Check the container
Before buying a used container, check the seller for warning signs and the container number for typos.
Who it’s for
Who it’s for
Importers and online sellers
Plan a first container, price it, and avoid surprise charges at the port.
Forwarders and customs brokers
Quick answers for customers, and calculators they can add to their own websites.
Logistics teams
Carrier free time and charges by port, with the source behind every figure.
What’s inside
What’s inside
12Free tools
11Ocean carriers’ demurrage and detention terms
23Shipping lines and lessors in the container lookup
51US port guides
8LTL carriers’ freight class rules
EN · ESEnglish and Spanish
As listed on dockmath.com, October 2026.
Where it stands
Where it stands
Now
Coming soon to dockmath.com, in English and Spanish.
First to open
Calculators for demurrage and detention, container loading, landed cost and freight class, a container tracking lookup, and a monthly free-time benchmark.