ISO 6346 check digit calculator.
Paste an 11-character container number and get an instant valid or invalid verdict, plus the owner code, category, serial, and check digit broken out. Runs entirely in your browser. No signup, no upload, no logs.
How is the ISO 6346 check digit calculated?
Each of the first 10 characters gets a value (letters map A=10 through Z=38, skipping multiples of 11), each value is multiplied by a power of 2 by position, the products are summed, and the sum modulo 11 gives the check digit, with a result of 10 written as 0. A container number that fails this test is not a valid ISO 6346 number, no matter how clean the scan looked.
What Vantage YMS does, from a phone.
Gate operations, C-TPAT inspection, live yard map, carrier appointments, driver-license capture, task dispatch, analytics — and a 5-stage AI OCR pipeline that reads container numbers in rust, fog, and faded paint.
5-stage AI validation
Photo, not typing.
A clerk photographs the number from a phone. Works offline, no kiosks, no fixed cameras at the gate.
Checked before it lands.
Every read is verified through a 5-stage AI validation pipeline, so an inconsistent number is flagged instead of written to the gate log.
The right number, first time.
Reads container numbers in rust, fog, and faded paint, so bad reads get caught at the gate, not three hours later in the yard.
…and a full yard management system
Gate IN / OUT.
End-to-end gate transactions — container, trailer, driver, seal, and appointment all linked at the moment of scan.
C-TPAT 7-point inspection.
Digital 7-point checklist with photo audit pack, GPS, timestamp, driver signature, and SHA-256 content hash for audit support. Included on Pro and above.
Live yard map.
Real-time slot view. Manager sees every door, every move from any browser. Drivers and forklift operators get tasks instantly.
Self-serve appointments.
Carriers book, edit, and track without a phone call. Public tracking link for shippers — no login required.
Driver license scan.
PDF417 + AAMVA parser auto-fills name, DOB, expiration, class for US / CA licenses. No re-keying. Photo retained for incident review.
Task assignment.
Yard drivers and forklift operators get prioritized task queues by site, shift, and skill — every move logged to the audit trail.
Analytics & KPIs.
Throughput, detention exposure, gate dwell, inspection pass-rate, OCR accuracy — every dashboard you'd expect from a $50K YMS.
14-day offline queue.
Walk into a dead zone, finish the cycle, sync on reconnect. The gate never stops because the network did.
No fixed gate hardware.
The phone replaces kiosks, RFID, scanner guns, and camera towers. Spin up a new yard before lunch.
Bilingual ready.
EN · ES · KO · ZH at login. US 3PLs with Spanish-speaking gate staff get an immediate first-day fit.
Published, $149+/mo.
No sales call required — but we're happy to hop on one. No five-figure annual contract. Lite $149, Pro $349 with C-TPAT inspection, Scale $649. 14-day free trial with no setup fee — payment method required at sign-up, no charge until day 15. Cancel anytime.
Multi-site, multi-tenant.
One organization, multiple yards. Site-scoped permissions, per-site KPIs, and Row Level Security on every query.
Frequently asked
Does this tool send my container number anywhere?
No. The calculator runs entirely in your browser. Nothing is uploaded, logged, or stored — you can disconnect your network and it will still work.
A valid check digit means the container is real, right?
Not necessarily. A valid check digit confirms the number is internally consistent, not that it belongs to a real, registered container. Vantage YMS pairs this with your appointment data so a valid-but-unexpected container gets flagged at the gate, not after the fact.
Does this work for trailer numbers and US domestic intermodal?
This calculator covers ISO 6346 sea/ocean containers only. Vantage YMS itself reads container numbers, trailer numbers, license plates, and chassis numbers — but that's a job for the app, not this tool.
The other free tools
Put this calculator on your own site
Free to embed on any site, no permission or attribution needed beyond the small credit line inside the widget. It loads a stripped-down view with no header, no footer, and no marketing.
Skip the math. Let the phone do it.
Vantage YMS — 14-day free trial. Cancel anytime. First scan typically under 10 minutes after sign-up.