How many desiccant units does a 40ft container need?

As a guide, a 40ft container with standard cargo needs about 6 to 8 one-kilogram calcium chloride units, and 10 to 12 for hygroscopic or timber-packed cargo, fewer with higher-capacity BE DRY ULTRA. The exact figure follows the DIN 55473 method from container volume, packing-material weight, barrier films and voyage duration; use the calculator above for an estimate and contact BENZ for a verified figure.

How is the desiccant quantity calculated?

The DIN 55473 / 55474 method sums the moisture held by the enclosed air and released by hygroscopic packing materials, then divides by the working capacity of one desiccant unit. This calculator applies that model to your container volume, cargo type and voyage length to estimate the number of BE DRY or BE DRY ULTRA units.

Is the desiccant calculator accurate?

It gives a reliable indicative estimate based on the DIN 55473 model and typical moisture loads. A binding specification also accounts for the absolute humidity at sealing, the exact weight of hygroscopic packing and barrier-film transmission, which the BENZ technical team calculates free of charge for your shipment.

Desiccant Calculator | How Many Container Desiccant Units (DIN 55473)

Container Desiccant Calculator

How many desiccant units does your container need? Enter the container, cargo and voyage below for an instant estimate based on the DIN 55473 method, in BE DRY and BE DRY ULTRA units. For a binding figure, our engineers run the full calculation free of charge.

Indicative estimate · DIN 55473 / 55474 method · BENZ Packaging

Estimate Your Desiccant

1. Container or sealed enclosure

2. Cargo & packing (moisture load)

3. Voyage / storage duration: 30 days

Estimated water vapour your desiccant must capture over the voyage.

RECOMMENDED0× 1kg BE DRY™ ULTRA units

0× 1kg BE DRY™ units

How this is calculated ↓

Indicative estimate using the DIN 55473 / 55474 model. The binding figure also depends on the absolute humidity at sealing, the exact weight of hygroscopic packing and any barrier films — our engineers calculate it free of charge. Get a verified figure →

The DIN 55474 Method, in Plain Text

DIN 55474 sizes desiccant by Desiccant Units (DU) — standardised absorption capacity, not raw weight. The number of units required is:

n = (1 / a) × ( V·b + m·c + A·e·D·t )

n total desiccant units (DU / TME) required
a water one unit binds at the target humidity — about 3 g at 20% RH, 6 g at 40% RH
V·b internal volume (m³) × moisture in the sealed air (b ≈ 15 g/m³ at 20°C, 85% RH)
m·c weight of hygroscopic packing (kg) × its moisture-content factor
A·e·D·t barrier-foil area × factor × water-vapour transmission (g/m²/day) × days in transit

The estimator above applies this method with typical values for each cargo class. Send your exact dimensions, packing weight and barrier foil for a binding figure.

Hang units high at the door end, midpoint and rear, and install just before sealing. How container desiccants work →

Typical Quantities (BE DRY, 1kg units)

Container & cargo	~25-day route	~45-day route
20ft · standard cargo	3–4	5–6
20ft · hygroscopic cargo	5–6	7–8
40ft · standard cargo	6–8	9–11
40ft · hygroscopic cargo	10–12	13–16

BE DRY ULTRA carries more water per unit, so it needs roughly a fifth fewer units than the figures above.

What Changes the Number

Packing material. Timber pallets, cartons and kraft paper hold litres of bound water — the single biggest driver after volume.
Humidity at sealing. A box closed in damp or tropical air starts loaded with moisture before it sails.
Voyage length. More days at sea means more day-night cycles releasing water onto the cargo.
Barrier films & liners. A sealed liner cuts the air exchange and changes the calculation.

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Container Desiccant Calculator

Estimate Your Desiccant

The DIN 55474 Method, in Plain Text

Typical Quantities (BE DRY, 1kg units)

What Changes the Number

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