Bulk Cargo
Draft Survey Calculator: Bulk Cargo Weight for Settlement
Calculate bulk cargo weight for invoice settlement using draft survey methodology. Model vessel displacement, ballast, and constant adjustments.
Draft SurveyBulk CarrierUN ECE / ISO 22337
Initial Survey (arrival, before loading/discharge)
Initial Drafts (m)
Initial Hydrostatics
Initial Deductibles (MT)
Final Survey (completion)
Final Drafts (m)
Final Hydrostatics
Final Deductibles (MT)
Cargo Quantity
26988.9MT
B/L Difference
+3488.9MT
14.85% - outside 0.5% tolerance
Initial Net Displacement
17342.7MT
Mean of means 8.610 m
Final Net Displacement
44331.6MT
Mean of means 12.310 m
Initial Corrections
10.1MT trim
Density corr. -107.4 MT
Final Corrections
20.9MT trim
Density corr. -314.3 MT
Overview & methodology
What is a draft survey?
A draft survey is a method of determining the weight of cargo loaded or discharged from a vessel by measuring the displacement change. In 2026, it remains the primary method for bulk commodities (coal, ore, grain) where weighbridge data is unavailable or inconsistent.
Numerical Example: Cargo Quantity Determination
The survey shows a 2.13% difference from the Bill of Lading, exceeding the 0.5% tolerance.
Initial Net Displacement22,000 MT
Final Net Displacement46,000 MT
B/L Quantity23,500 MT
Survey Quantity24,000 MT
B/L Difference+500 MT (2.13%)
Source: UN ECE - UN ECE Code of Practice for Draft SurveysOfficial Resource
Last reviewed: August 2026
Frequently asked questions
How is cargo quantity calculated from a draft survey?
Take the six drafts, compute the mean of means, apply trim (first and second) and density corrections to displacement, then subtract deductibles (ballast, fresh water, fuel, stores, constants). Cargo = final displacement on completion − final displacement on arrival.
What tolerance applies between the draft survey and the B/L figure?
Commercially, a draft survey is accepted to about ±0.5% against the bill of lading quantity. Larger differences normally trigger a re-survey, a letter of protest, or a shore-scale reconciliation before the master signs.
Advertisement728 × 90
Related calculators
All Bulk Cargo tools →Coal & Petcoke Quality Calculator
GAR/NAR/ADB/DB/DAF basis conversion, gross-to-net calorific value and CV price adjustment with penalties.
Stowage Factor & SF Converter
Convert between FT/MT and M3/MT, calculate volume requirement and cargo mix.
Bulk Shipment Profitability Calculator
FOB-to-CIF margin, freight exposure, demurrage-adjusted profit and break-even MT.
Advertisement728 × 90