CargoSum
Tools / Demurrage Calculator

Demurrage Calculator

Chargeable days and tiered charges for container demurrage or detention — from your own tariff's free time and daily rates.

CONTAINER TIMELINE
TARIFF TIERS (PER CONTAINER, PER DAY)
CHARGEABLE DAYS714 days at port − 7 free
PER CONTAINER$1,350.00
TOTAL$1,350.001 container
TierDaysRate/dayAmount
Tier 15$150.00$750.00
Tier 22$300.00$600.00

Day counting assumes calendar days with discharge day as day 1, pickup day included — some tariffs count working days or exclude the first day, and free time and rates vary by carrier, port and contract. Enter the tiers from your own agreement; this tool does the arithmetic, not the tariff.

The most avoidable charge in container shipping

Demurrage exists to keep terminals fluid: containers that overstay their free time occupy space the port needs, so the daily rate climbs steeply — a third-tier day can cost more than the ocean freight itself on short lanes. The math is simple multiplication, but the stakes come from the tiers: knowing on which calendar day your container crosses into the next rate band tells you exactly what a one-day delay costs, and whether paying for a Saturday pickup beats paying another tier day.

Charge = Σ tier days × tier rate, days = time at port − free time
What is demurrage?

Demurrage is the charge a shipping line bills when an import container stays at the terminal beyond its free time — the allowance of days included in the freight. It accrues per container, per day, usually on an escalating tier scale, until the container is picked up.

What's the difference between demurrage and detention?

Demurrage covers the container sitting inside the terminal; detention covers the container out of the port but not yet returned empty to the carrier. Both use the same free-time-plus-daily-rate mechanics, which is why this calculator works for either — enter the matching tariff.

How are demurrage days counted?

Most tariffs count calendar days with the discharge day as day one and the pickup day included, but conventions differ — some count working days, some exclude the first day, some pause for port closures. This tool uses the common calendar-day convention; check your carrier's tariff wording for the exact rule.

Embed this calculator on your site

Free to embed — paste this snippet into your page. It stays free, has no ads inside, and links back to us.

Add ?theme=light (or ?theme=dark) to the embed URL to lock the color theme regardless of the visitor's system setting.

<iframe id="cargosum-demurrage-calculator" src="https://cargosum.com/embed/demurrage-calculator/" width="100%" height="640"
  style="border:1px solid #ddd;border-radius:4px" title="Demurrage Calculator — CargoSum" loading="lazy"></iframe>
<p>Calculator by <a href="https://cargosum.com/demurrage-calculator/">CargoSum Demurrage Calculator</a></p>
<script>window.addEventListener("message",function(e){if(e.origin==="https://cargosum.com"&&e.data&&e.data.type==="cargosum:embed-height"){var f=document.getElementById("cargosum-demurrage-calculator");if(f&&e.source===f.contentWindow)f.style.height=e.data.height+"px";}});</script>