MojiTrend Tools

Demurrage & Detention Calculator

Estimate container demurrage and detention charges from discharge, pickup, empty return, free days, daily rates, and quantity. This independent calculator uses the values you enter and does not rely on live carrier or port tariffs.

1. Container information

2. Date inputs

Combined mode uses only the discharge / availability date and empty return / gate-in date. Switch to Separate mode if you need pickup / gate-out for detention.

3. Pricing inputs

Optional advanced day counting
Choose specific weekdays to exclude

Default: calendar days, start date not counted, end date counted, weekends included.

Timeline overview

  1. Discharge / availability10 Jun 2026counting starts
  2. Free time ends15 Jun 2026chargeable days begin after this point
  3. Empty return / gate-in23 Jun 2026final date used

Combined Demurrage & Detention

Calculation modeCombined D&D

Movement typeImport

Container type20 ft Dry / Standard (DR20)

Quantity1 container

Period10 Jun 2026 → 23 Jun 2026

Total counted days13

Free days5

Chargeable days8

Rate typeFlat

Flat rate€80 / day

Estimated charge€640

Estimate only. Final charges may differ. Always verify with your carrier, terminal, or freight forwarder.

Privacy-first: this tool runs in your browser. We do not upload, store, or sell the values you enter.

How to calculate demurrage charges

Demurrage usually relates to the time a container stays at the terminal after the allowed free time. In this calculator, demurrage is estimated as:

Chargeable demurrage days = max(0, terminal days - demurrage free days)

Demurrage charge = chargeable demurrage days × demurrage daily rate × quantity

How to calculate detention charges

Detention usually relates to the time a container remains outside the terminal before the empty container is returned. In this calculator, detention is estimated as:

Chargeable detention days = max(0, equipment days - detention free days)

Detention charge = chargeable detention days × detention daily rate × quantity

Combined demurrage and detention

Some tariffs combine demurrage and detention into one free time period. In combined mode, the calculator counts the period from discharge or availability date until the empty return date, subtracts the free days, and applies the entered rate or tiered rates.

Why rates are not prefilled

Demurrage and detention rates vary by carrier, port, terminal, country, equipment type, contract, free time agreement, and date. Mojitrend does not provide official live rates. Enter the rates from your carrier quote, tariff sheet, freight forwarder, or invoice to estimate the charge.

Example calculation

Example: 2 containers have 13 counted combined D&D days. If the free time is 5 days, the chargeable time is 8 days. At €80 per day, the estimated charge is 8 × €80 × 2 = €1,280.

Common mistakes

  • Using pickup / gate-out in combined mode when the tariff counts through empty return.
  • Mixing calendar days and working days without checking the carrier or terminal rule.
  • Forgetting to multiply the result by container quantity.
  • Using a flat rate when the tariff changes after day 5 or day 10.
  • Treating the estimate as an invoice instead of checking the final carrier or terminal charge.

Frequently asked questions

Are demurrage and detention the same?

No. Demurrage usually refers to container time at the terminal after free time expires. Detention usually refers to the time the container is outside the terminal before the empty container is returned. Some carriers also offer combined demurrage and detention free time.

Does this calculator use official carrier rates?

No. This calculator does not use live or official carrier tariffs. It estimates charges from the rates, free days, dates, and quantity entered by the user.

What is free time?

Free time is the number of days allowed before demurrage or detention charges begin. Free time depends on the carrier, terminal, port, equipment type, route, and contract.

Should I use calendar days or working days?

Many tariffs use calendar days, but some agreements may exclude weekends or holidays. Check your carrier or terminal tariff and use the day counting options that match your agreement.

Why can the final invoice differ from this estimate?

The final invoice may include different day counting rules, local holidays, taxes, VAT, storage charges, customs delays, previous payments, special agreements, or carrier-specific tariff rules.

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