Port Disbursement Account (PDA) Estimator: Call Costs

Formula, assumptions, and limits

To estimate a disbursement account, add the line items the call will incur and normalize by the ship’s size:

$$DA = \sum_i L_i \qquad \text{USD/GT} = \frac{DA}{GT}$$

L_i - one line of the proforma: port dues, pilotage, towage, mooring, agency fee, and the call-specific extras. GT - gross tonnage per the ship’s ITC 1969 tonnage certificate, the figure most port tariffs reference.

The tool is an adding machine with the right categories, deliberately: every port prices differently, so the honest inputs are the lines from the agent’s proforma disbursement account (PDA) or the port authority’s published tariff, not built-in rates that would be wrong everywhere except one port in one tariff year. What the calculator adds is structure: the standard line set, the USD/GT normalization that makes calls comparable, the largest line and its share, and a breakdown chart to set against the final DA.

Assumptions and limits: cargo-related dues (wharfage on cargo, stevedoring) belong to the cargo interests under most charter terms and are excluded from the default rows; add them where your terms put them on the ship. Canal transits, bunkering calls, and husbandry-only calls have their own line structures. Exchange-rate movement between proforma and final DA sits outside the tool: enter everything in one currency.

How to use this calculator

1. Enter the vessel’s gross tonnage from the ship’s particulars.
2. Enter the line items from the agent’s PDA or the port’s published tariff: port dues, pilotage, towage, mooring and unmooring, and the agency fee.
3. Add rows for the call-specific lines: garbage, launch hire, immigration, certificates, cargo dues where your terms carry them.
4. Read the DA total, the USD per gross ton, and the largest line’s share.
5. Keep the breakdown; when the final disbursement account (FDA) arrives, set it against this estimate line by line.

Where each input comes from

• Gross tonnage: the ship’s particulars; tariffs reference the ITC 1969 figure, not deadweight.
• Port dues: the port authority’s published tariff, usually per GT or per 100 GT; the port dues calculator turns the tariff rate into the line figure.
• Pilotage and towage: the pilotage district and tug operator tariffs, banded by size and per movement; two movements (in and out) unless the call shifts berth.
• Mooring, agency fee, extras: the agent’s proforma DA. The agency fee is the one line the agent sets itself; the rest the agent passes through at cost, which is why the proforma-versus-final comparison is the owner’s control.

Worked example

A 40,000 GT bulk carrier, one cargo call. Port dues USD 18,000, pilotage USD 6,500 for the two movements, towage USD 14,000 (two tugs, in and out), mooring and unmooring USD 2,200, agency fee USD 3,500, garbage and launch extras USD 1,800. DA total: USD 46,000, or USD 1.15 per GT. Port dues lead the DA at 39%, with towage second at 30%; towage is nonetheless the line where the final DA most often diverges from the proforma, because tug count is the pilot’s call: an extra tug ordered on the day, or a shifted berth, lands there. All figures are illustrative inputs in the shape real proformas take, not any port’s tariff.

Reading the final DA against this estimate

The proforma-to-final comparison works line by line, and the lines behave differently. Port dues and pilotage are tariff arithmetic: a variance there means a wrong GT, a wrong band, or a tariff change, all checkable. Towage varies with operations: tug count and weather are real, but “additional services” without a pilot’s or master’s note are queryable. The extras block is where unrequested launches, gratuities recast as fees, and double-charged certificates surface; an itemized final DA, vouchers attached, is the standard demand when the block grows between proforma and final. The statement of facts is the cross-check for the operational lines: tug counts, movement times, and launch runs on the final DA should reconcile against what the SOF records, and a line the SOF cannot support is the first one to query. Owners that benchmark calls in USD/GT across their fleet catch systematic leakage that single-call review misses.

The estimating mistakes feeding bad proformas are stable too. Deadweight in the GT field is the classic: tariffs reference GT per the ITC 1969 certificate, and a 40,000 dwt ship is not a 40,000 GT ship. A single pilotage movement where in and out are separately charged understates that line by half. Currencies get mixed when tariffs publish local and agents quote USD. And the ship’s own small services, garbage (mandatory in many ports under MARPOL reception arrangements), fresh water, launch hire, are real money across a fleet’s year even when each line looks trivial on one call.

About This Port Disbursement Account Estimator

A disbursement account (DA) is the itemized statement of every cost a vessel’s port call incurs: port dues, pilotage, towage, mooring, agency fee, and incidentals. The proforma is the document a master, an operator, and an owner all read before the ship arrives. This estimator is for voyage estimators, operations desks, and agents who need a structured proforma quickly: it takes the standard line items plus any number of extras, and returns the call total, the USD per gross ton, and the share of each line.

The line set mirrors the proforma convention: port dues, pilotage, towage, mooring and unmooring, agency fee, then the call-specific extras. The USD/GT normalization is the fleet benchmark figure, and the largest-line readout points at where the money sits, while the variance discipline points at towage and the extras regardless of which line leads. Nothing is pre-priced, because port tariffs differ by port, ship size, and tariff year; the structure, the normalization, and the comparison discipline are what transfer between calls.

The chart draws each line as a bar with hover and keyboard tooltips and a table fallback, the same anatomy view an owner uses to read a final DA against its proforma. For the tonnage-driven line, the port dues calculator computes the tariff arithmetic; for the cargo side of a call’s costs, the THC calculator covers the container handling lines.

Further reading

• Disbursement account
• Port dues
• Port dues calculator
• THC calculator

Frequently asked questions

What is a disbursement account in shipping?

The disbursement account (DA) is the itemized statement of everything a vessel's port call costs: port dues, pilotage, towage, mooring, agency fee, and incidentals. The appointed agent issues a proforma DA before the call for funding, then a final DA after sailing with the actual figures.

What does a port call cost?

It depends on the ship's size, the port's tariff, and the services taken: the same vessel can see totals differ severalfold between ports. The structure is stable though: port dues scale with gross tonnage, pilotage and towage with size and movement count, and the agency fee is a flat or banded figure.

What is the difference between a PDA and an FDA in shipping?

The PDA (proforma disbursement account) is the agent's pre-call estimate, used to call funds in advance. The FDA (final disbursement account) replaces estimates with actual invoices after the call. Comparing the two, line by line, is the standard owner's control on port-cost leakage.

Why divide the DA by gross tonnage?

USD per GT puts calls by different ships at different ports on one scale. Port dues themselves are tariffed per GT in most ports, so the normalization also separates the tonnage-driven lines from the service-driven ones like towage.