Freight reference
How to Calculate Worldscale Tanker Rates
Worldscale freight starts with the applicable WS100 flat rate in US dollars per metric tonne. Multiply that rate by the negotiated Worldscale points divided by 100 and by cargo quantity, then apply additions, variable or fixed differentials, and supplementary items according to their official wording.
Worldscale is a nominal tanker freight scale for oil and oil products carried in bulk by sea. It makes route-specific freight levels comparable by expressing a negotiated market level as a percentage of the applicable WS100 flat rate. This guide explains the arithmetic but does not reproduce the licensed Worldscale Schedule or supply a current route rate.
Worldscale freight formula
For a simple voyage with no separate differential, the basic relationship is:
Basic freight = WS100 flat rate × (Worldscale points ÷ 100) × cargo quantity
The official Worldscale guidance gives the fuller sequence as the flat rate, including applicable additions, multiplied by the Worldscale equivalent and cargo quantity; variable differentials are then treated with the Worldscale equivalent, fixed differentials follow their own wording, and relevant supplementary-message items are added.
Worked Worldscale calculation
Assume an illustrative WS100 flat rate of $20.00 per metric tonne, a cargo quantity of 50,000 metric tonnes, and a negotiated market level of WS125. These numbers demonstrate the formula only; they are not a current rate for any route.
| Step | Calculation | Result |
|---|---|---|
| Convert WS125 to a multiplier | 125 ÷ 100 | 1.25 |
| Negotiated rate per metric tonne | $20.00 × 1.25 | $25.00/MT |
| Basic freight payment | $25.00 × 50,000 MT | $1,250,000 |
How to calculate the rate step by step
- Identify the exact load port, discharge port, routing, edition, and voyage assumptions.
- Obtain the authorized WS100 flat rate and all notes, additions, differentials, charterers' account items, and supplementary messages for that voyage.
- Convert the negotiated market level to a multiplier: WS75 is 0.75, WS100 is 1.00, and WS175 is 1.75.
- Multiply the percentage-bearing flat rate by that multiplier and the billable cargo quantity.
- Apply variable differentials with the Worldscale equivalent where instructed.
- Apply fixed differentials exactly as worded; do not automatically multiply them by the Worldscale points.
- Add or deduct any separately agreed charter-party items and reconcile the result with the fixture recap and final cargo quantity.
What WS100, WS75, and WS175 mean
| Quoted level | Flat-rate percentage | Multiplier | Example at a $20/MT flat rate |
|---|---|---|---|
| WS75 | 75% | 0.75 | $15/MT before other items |
| WS100 | 100% | 1.00 | $20/MT before other items |
| WS125 | 125% | 1.25 | $25/MT before other items |
| WS175 | 175% | 1.75 | $35/MT before other items |
Additions and differentials
Additions can form part of the percentage-bearing voyage rate for specified loading areas. Variable differentials address costs that depend on factors such as cargo type or loading and discharging amounts and generally take the negotiated Worldscale equivalent. Fixed differentials can be payable separately or included in freight, and the Worldscale percentage does not automatically apply to them.
These distinctions can materially change a payment. Use the exact current Worldscale voyage output and read its notes rather than copying an undated flat rate or treating every extra charge the same way.
Use and limitations
This page is an independent educational calculation guide, not a live tanker-rate service, fixture confirmation, freight invoice, chartering recommendation, or substitute for the current licensed Worldscale Schedule. It does not account for every addition, differential, supplementary message, charterers' account item, cargo tolerance, deadfreight, demurrage, despatch, brokerage, commission, tax, currency, or charter-party term. Confirm the authorized voyage record and signed contract with qualified chartering and accounting professionals.
Frequently asked questions
How do you calculate a Worldscale tanker freight payment?
Multiply the applicable WS100 flat rate, including percentage-bearing additions, by the negotiated Worldscale points divided by 100 and by cargo quantity. Then apply variable and fixed differentials and supplementary items exactly as the official voyage record and charter party require.
What does WS100 mean?
WS100 means 100% of the applicable Worldscale flat rate for the voyage. The official Worldscale explanation describes it as the nominal rate for the Standard Vessel under that edition's basis of calculation; it is not a break-even statement for every actual ship.
What do WS75 and WS175 mean?
WS75 means 75% of the applicable flat rate, while WS175 means 175% of it. Divide the quoted Worldscale number by 100 to obtain the multiplier used in the basic freight calculation.
Where do I get the current WS100 flat rate?
Use an authorized Worldscale subscription or request the applicable rate from the Worldscale Associations. Freight Totals does not reproduce licensed route-rate tables.
Do all differentials get multiplied by the Worldscale percentage?
No. Worldscale distinguishes variable differentials, which generally take the Worldscale equivalent, from fixed differentials whose treatment depends on their wording. Follow the current voyage record, supplementary messages, and charter party.
Sources
The newest source record below was captured 2026-08-25. This date identifies the stored record, not currentness; follow the link before purchasing, rating, or loading.