Free Demurrage Calculator
A container sitting at Felixstowe for 10 days past free time costs you £1,000–£3,000. How many containers do you move a month?
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Why Payment Speed Determines Your Demurrage Costs
Most importers treat demurrage as a shipping problem. It's not. It's a payment speed problem. Here's the chain: slow payment → delayed document release → container sitting at port → £150/day penalty.
Understanding Demurrage and Detention Charges
Demurrage is the charge applied when a shipping container remains at the port terminal beyond its allotted free time. Detention is the charge applied when a container remains in your possession — at your warehouse, depot, or freight forwarder's facility — beyond its allotted free time. Both are daily charges that accumulate rapidly and can transform a profitable shipment into a loss-making one.
The standard free time allowance at most ports is 5-7 days for demurrage and 4-7 days for detention, though this varies by shipping line, port, and trade lane. After free time expires, charges typically start at $75-$150 per container per day and escalate on a tiered basis — often doubling after the first week and tripling after the second.
A single 40-foot container held for 10 days beyond free time can accumulate $1,500-$3,000 in combined demurrage and detention charges. For importers managing multiple containers per month, these costs can reach five or six figures annually. For a comprehensive breakdown of how these charges work, see our complete demurrage guide. For the link between demurrage and working capital, see our Week 4 article.
The connection between payment speed and container costs
What most importers don't connect is the direct relationship between international payment speed and demurrage exposure. Here's the chain:
Your supplier ships goods and sends you an invoice requiring payment before releasing shipping documents. Your bank processes the international payment, which takes 3-5 business days through standard SWIFT channels. The payment clears. Your supplier releases the bill of lading and commercial documents. You present documents to customs and arrange container collection. Every day between the container arriving at port and you collecting it accumulates demurrage charges.
If your payment takes 5 days instead of 1, and document release takes another 2 days as a result, you've burned through your entire free time allowance before you could physically collect the container. The demurrage charges that follow are a direct cost of slow payment settlement.
Faster FX settlement — same-day or next-day rather than T+3 to T+5 — can eliminate 2-4 days from this chain, keeping your container within free time and avoiding demurrage entirely. On a single container, that's $150-$600 saved. Across 50 containers per year, it's $7,500-$30,000.
Frequently asked questions
How is demurrage calculated?
Demurrage = (Number of days beyond free time) × (Daily demurrage rate). Rates vary by shipping line and port but typically range from $75-$300 per container per day, with escalating tiers.
What is the difference between demurrage and detention?
Demurrage applies while the container is at the port terminal. Detention applies while the container is in your possession away from the port. Both are time-based charges for exceeding free time allowances.
Can demurrage be avoided?
Yes. Pre-clearing customs documentation, ensuring payment documents are released before vessel arrival, and using faster payment speed settlement all reduce the time between container arrival and collection.
How do payment delays cause demurrage?
Many suppliers withhold shipping documents until payment clears. If your international payment takes 3-5 days via bank SWIFT transfer, those days directly extend the time before you can collect your container from port. Faster settlement through specialist FX providers can eliminate this delay.
Unicorn Currencies Limited is a FINTRAC registered Money Services Business (MSB C100000159) and Bank of Canada RPAA registered payment service provider.
How to Avoid Demurrage Charges
The Problem
- Free time expires fast: Typically 3-5 days at UK ports
- Costs add up quickly: £150/day for 40ft container
- No automatic alerts: You manually check container status
- Customs delays: Unexpected hold-ups cause penalties
- Weekend blindspot: Free time keeps counting
Annual impact: £1,000-£2,000 per container. 10 containers = £10k-£20k wasted annually.
The Solution: Automated Alerts
- 48-72h advance alerts: Know before free time expires
- Real-time tracking: Monitor all containers in one dashboard
- SMS + Email: Never miss a deadline
- Port-specific timings: Accurate free time calculations
- Weekend coverage: Alerts 24/7
Unicorn Currencies customers save £5k-10k annually by avoiding demurrage with FREE container tracking.
Real Customer Example
"We import textiles from India. Before Unicorn Currencies, we paid £1,200 in demurrage on ONE shipment because customs clearance took 8 days and we didn't notice. Now we get alerts 72 hours before free time expires. We haven't paid demurrage in 14 months. Saved us £8,400 last year."
Frequently Asked Questions
What is demurrage?
Demurrage is a fee charged by shipping lines when containers are not collected from the port within the allocated free time period. At UK ports, demurrage charges typically range from £100 to £200 per day per container. The free time period is usually 3-7 days, after which daily charges begin accumulating. These fees compensate the shipping line for the use of their container and port storage space beyond the agreed timeframe.
How does this demurrage calculator work?
Our free demurrage calculator estimates your potential container charges based on three inputs: your UK port (Felixstowe, Southampton, London Gateway, or Liverpool), container type (20ft, 40ft, or 40ft high cube), and the number of days past the free time period. The calculator uses current average demurrage rates for each port and container size to provide an accurate cost estimate, helping you understand the financial impact of delays.
How can I avoid demurrage fees?
The most effective way to avoid demurrage fees is to use automated container tracking with advance alerts. Unicorn Currencies offers FREE container tracking for import/export businesses with $1M+ annual FX volume. Our system sends SMS and email alerts 48-72 hours before your free time expires, giving you time to arrange collection, resolve customs issues, or coordinate with your freight forwarder. Customers using our tracking save £5,000-£10,000 annually on average.
What is the average demurrage cost in the UK?
UK ports typically charge between £100 and £200 per day per container for demurrage, with rates varying by port and container size. 40ft containers cost more than 20ft containers, and high cube containers attract premium rates. On average, UK businesses lose £5,000 to £10,000 annually due to demurrage charges. A single delayed shipment can cost £1,000-£2,000 in unexpected fees, making proactive container tracking essential for importers.
Does Unicorn Currencies help with demurrage?
Yes, Unicorn Currencies offers FREE container tracking for enterprise customers with $1M+ annual FX volume. Our tracking system is linked directly to your international payments, automatically monitoring shipments and sending 48-72 hour advance alerts before demurrage charges begin. This integrated approach helps businesses avoid unnecessary fees while managing their international trade payments. Customers using our tracking system save an average of £5,000-£10,000 per year in avoided demurrage charges.
$1M+ in Imports? Get FREE Container Tracking
48-72h demurrage alerts. Real-time shipment monitoring. Save £5k-10k annually. For import/export businesses with $1M+ annual FX volume.
FREE container tracking for businesses with $1M+ annual FX volume. Not available for consumer accounts.