20ft Container Carton Calculator
How many of your cartons fit in a 20ft container — best orientation, load rate, total units and goods value.
Booking a 20ft container against a carton count guessed from volume alone is how shipments end up short — or with cartons left on the dock. Volume division ignores the fact that cartons are rigid boxes: what matters is how many whole cartons fit along each internal dimension. This calculator does the honest version of that maths. It tries all six ways of turning your carton (length, width and height each taking a turn along the container’s length, width and height), keeps the orientation that fits the most cartons, and reports the count, the volume load rate and the total weight next to the container’s payload limit.
Enter one packed carton’s outside dimensions. The calculator tries all six orientations inside a standard 20GP (internal 589.8 × 235.2 × 239.3 cm) and keeps the best, then checks the total weight against the 28,180 kg reference payload.
Estimate only — not a loading plan. Your unit cost and the goods value stay in this page’s memory: never sent, stored, or written into the URL. Container basis: Hapag-Lloyd 20GP specification, checked November 2026.
Quick answers
How many cartons fit in a 20ft container?
It depends entirely on the carton. For each of the six orientations of the carton, divide the container’s internal length (5,898 mm), width (2,352 mm) and height (2,393 mm) by the carton side facing that way, round each down to whole cartons, and multiply the three counts. The best orientation wins. A 60 × 40 × 40 cm carton, for example, fits 9 × 5 × 5 = 225 to a 20GP.
That is why a single “cartons per container” number quoted without a carton size means nothing: the same container holds 225 of the cartons above but only 176 of a 50 cm cube, even though the cube load uses slightly more of the volume (66.3% against 65.1%). Shape, not just size, decides the count.
Why is the load rate never close to 100%?
Because cartons are rigid and containers are fixed: unless every carton side divides its container dimension exactly, the leftover strips along the length, width and height are unusable by that carton. Real 20GP loads of a single carton size typically land between about 55% and 85% volume use; mixed carton sizes, packed to fill each other’s gaps, do better.
The load rate on this page is loaded carton volume divided by the container’s 33.2 CBM internal volume. A low rate with a high carton count is not a problem to fix — it is the geometry of your carton. If the rate matters more than the count (you pay for the whole container either way), a small carton redesign that divides 5,898, 2,352 or 2,393 mm more evenly can be worth more than any packing trick.
What limits a 20ft container load first — space or weight?
Whichever runs out first. This page checks both: the carton count by space, and the count the reference maximum payload of 28,180 kg allows at your per-carton weight. Dense cargo (tiles, liquids, metal parts) usually hits the weight limit with most of the space empty; light, bulky cargo fills the space at a fraction of the payload.
The worked example on this page shows the weight limit binding hard: a 50 cm cube at 200 kg per carton fits 176 by space, but only 140 by weight. Road weight limits at the destination can bind earlier still — the container may legally carry more than the truck that collects it — which is one more reason the result here is a planning estimate, not a booking instruction.
How to use
- Measure one packed carton’s outside length, width and height, and enter them in centimetres or inches.
- Add the gross weight per carton if you want the payload check — leave it blank and the page calculates space only, and says so.
- Optionally add units per carton, and your per-unit purchase cost, to get the load’s total units and total goods value.
- Read the loadable count (the lower of the space and weight counts), the winning orientation, the load rate, and the full six-orientation table before you book.
About this tool
The container basis is stated, not hidden: a standard 20GP with internal dimensions of 5,898 × 2,352 × 2,393 mm, about 33.2 CBM, and a reference maximum payload of 28,180 kg from Hapag-Lloyd’s published container specification. Individual boxes differ — some fleets rate the same size of container to a higher payload, older units to less — so treat the payload here as a planning figure and the container’s door plate as the final word. Note too that the door opening, roughly 2,280 mm high, is lower than the 2,393 mm inside: a stack built to the full internal height still has to get through the door.
Two optional fields turn the carton count into shipment numbers. Add the units in each carton and the calculator totals the units in the load; add your per-unit purchase cost as well and it totals the goods value of the load — the figure the Merchandise Processing Fee and landed-cost calculations start from. Those numbers exist only in this page, while it is open: cost and value are business data, so they are never written into the URL, never stored, and never sent anywhere.
Everything runs in your browser. Nothing you type is uploaded, sent to a server or stored.
How it works
Space count: for each of the six orientations of the carton, cartons along each axis = floor(container internal dimension ÷ carton side on that axis), using internal dimensions 5,898 × 2,352 × 2,393 mm. Orientation count = the three axis counts multiplied. The reported space count is the largest of the six. Load rate = (space count × carton volume) ÷ 33.196 CBM internal volume.
Weight count and totals: weight count = floor(28,180 kg ÷ gross weight per carton in kg). Loadable cartons = the smaller of the space and weight counts. Total gross weight = loadable cartons × weight per carton. Total units = loadable cartons × units per carton. Total goods value = total units × unit cost. Unit cost and goods value are calculated in page memory only and are never placed in the URL or stored.
Worked examples
A 60 × 40 × 40 cm carton, 12 kg, 24 units at $2.50: Best orientation keeps the 60 cm side along the container’s length: 9 along the length × 5 across × 5 high = 225 cartons. Loaded volume 21.6 CBM, a 65.1% load rate. Total weight 2,700 kg, well under the payload, so all 225 are loadable — 5,400 units, $13,500.00 of goods.
A 50 cm cube, 20 kg per carton: 11 × 4 × 4 = 176 cartons in any orientation, 22.0 CBM, a 66.3% load rate, 3,520 kg total. Space binds long before weight does.
The same 50 cm cube at 200 kg per carton: Space still allows 176, but the payload allows only floor(28,180 ÷ 200) = 140 cartons (28,000 kg). The page reports 140 as loadable and flags weight as the binding limit — the other 36 cartons need a second container or a different plan.
The 20GP basis used on this page
| Item | Value used | Note |
|---|---|---|
| Internal length | 5,898 mm | Standard 20GP, per Hapag-Lloyd container specification |
| Internal width | 2,352 mm | Corrugated walls make some series a few mm narrower |
| Internal height | 2,393 mm | Door opening height is lower: about 2,280 mm |
| Internal volume | 33.196 CBM (shown as 33.2) | Product of the three internal dimensions above |
| Reference maximum payload | 28,180 kg | Max gross 30,480 kg minus tare 2,300 kg in the same specification; your unit’s door plate governs |
Specification source: Hapag-Lloyd Container Specification, 20 ft general-purpose containers; dimensions checked November 2026. Payloads vary by build series — some fleets rate 20GP units higher.
Frequently asked questions
Is this a 3D container loading optimiser?
No. This calculator packs one carton size in one repeating grid orientation — the right model for the common case of a container filled with a single product’s cartons, and a deliberately simple one. Mixed-SKU 3D load planning, with cartons of different sizes filling each other’s gaps, is a different problem and is out of scope for this page; a freight forwarder’s loading software is the right tool for it.
Which 20ft container do the dimensions describe?
A standard-height 20ft general-purpose container (20GP): internal 5,898 × 2,352 × 2,393 mm, about 33.2 CBM, per Hapag-Lloyd’s published container specification. A 20ft high-cube is about 30 cm taller inside and holds more; a 20ft reefer is smaller inside because of its insulation and machinery. If you are quoted one of those, this page’s count will be off in the direction you would expect.
Why does the page say my load is overweight when the cartons fit?
Because fitting and being allowed are different checks. The count by space says the boxes physically fit; the payload check says what the container may carry. When weight binds, the page lowers the loadable count to the weight-based count and tells you which limit decided — shipping the space count anyway risks the carrier refusing the load or demanding a second container at the dock.
Should I enter the carton’s inside or outside dimensions?
Outside, as packed and sealed — that is the box the container has to hold, tape bulge and all. If your supplier quotes inner dimensions or the flat carton size, add the material thickness and a small allowance, or measure a finished carton yourself before relying on the count.
What happens to the unit cost and goods value I type?
They are used for the arithmetic on this page and nothing else: not sent to any server, not stored in your browser, and never written into the page’s URL (in the query string or after the #), so a copied link or a server log can never carry them. Close or refresh the page and they are gone. The total goods value is the starting figure for the Merchandise Processing Fee calculator linked below — you retype it there yourself, deliberately.
The count looks low next to my forwarder’s quote. Why?
Three usual reasons: the forwarder may be quoting a different container (high-cube or a 40ft), may be planning a mixed load that fills the leftover strips this single-size grid cannot use, or may be dividing volumes — 33.2 CBM ÷ your carton’s volume — which always overstates the count of rigid boxes. Ask which basis the quote uses; if it is volume division, this page’s count is the safer planning number.
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