Your supplier sends carton sizes in centimeters. Your US warehouse bills storage in cubic feet. Somewhere in between, the numbers need to match.
When they don’t, you find out on your first invoice: the warehouse measured more volume than you planned for, and the storage bill is higher than the quote you budgeted.
This guide shows you how to calculate cubic feet for storage from centimeters, inches and cubic meters, with worked examples you can copy. You’ll also see how carton size changes your monthly storage bill, and how 3PLs calculate storage by the actual volume your inventory takes up.
Key Takeaways
- Cubic feet = length × width × height in inches ÷ 1,728.
- From centimeters, divide by 28,317.
- From cubic meters, multiply by 35.315.
- Then multiply by the number of cartons to get your total storage volume.
Table of contents
- What is a cubic foot in warehouse storage?
- How to calculate cubic feet step by step
- How to convert metric dimensions to cubic feet
- Cubic feet calculation examples
- How carton dimensions affect storage cost
- How 3PL storage is calculated by actual volume
- Common cubic feet calculation mistakes
- How to lower your storage volume and cost
- FAQ – Calculating cubic feet for storage
- Conclusion
What is a cubic foot in warehouse storage?
A cubic foot is the space inside a cube that measures 12 inches (about 30.5 cm) on each side. It’s the standard unit US warehouses use to measure how much space your stored goods take up.
If you’ve rented self-storage before, those units are a handy reference point, since most have 8 ft ceilings:
- 10×10 storage unit cubic feet: about 800
- 10×15 storage unit cubic feet: about 1,200
- 10×20 storage unit cubic feet: about 1,600
Why 3PLs bill by volume. With cubic storage, you pay for the space your cartons actually take up, instead of a whole pallet position. That suits small and mixed inventory, which rarely fills a full pallet.
Cubic feet vs CBM. CBM (cubic meter) is the metric unit used in international trade and on most freight documents. One CBM equals 35.315 cubic feet. It’s the same space, measured in different units.
How to calculate cubic feet step by step
Calculating cubic feet takes four steps, whether you’re storing one carton or a full container:
- Measure the outside of each carton.
- Multiply length × width × height.
- Convert the result to cubic feet.
- Multiply by the number of cartons and add up each SKU.
Here’s each step in detail.
Step 1: Measure the cartons
Measure the outer dimensions of each carton as it will sit on the shelf, packaging included. Don’t measure the product inside: warehouses measure the outside of the box, so that’s the number your bill is based on.
If a carton is irregular or bulging, measure each side at its widest point and round up.
Step 2: Multiply length × width × height
Multiply the three measurements together, keeping all three in the same unit. If you measured in inches, the result is in cubic inches. If you measured in centimeters, the result is in cubic centimeters.
Step 3: Convert to cubic feet
From cubic inches, divide by 1,728, the number of cubic inches in a cubic foot (12 × 12 × 12):
Cubic feet = (L × W × H in inches) ÷ 1,728
From cubic centimeters, divide by 28,317, the number of cubic centimeters in a cubic foot:
Cubic feet = (L × W × H in cm) ÷ 28,317
Step 4: Multiply by the number of cartons and add up each SKU
If all your cartons are the same size, multiply the cubic feet per carton by the number of cartons. If you store several carton sizes or SKUs, calculate each one separately, then add the totals together. That sum is the storage volume a warehouse will bill you for.
Want a shortcut? Our storage calculators do the math for you.
How to convert metric dimensions to cubic feet
International suppliers usually send carton sizes in centimeters and shipment totals in cubic meters, while US warehouses bill storage in cubic feet. Here’s how to convert both.
Centimeters to cubic feet
Cubic feet = (L × W × H in cm) ÷ 28,317
You can also convert each side to inches first (cm ÷ 2.54), multiply them, and divide by 1,728. You’ll get the same result, with more steps and more chances to slip.
Cubic meters (CBM) to cubic feet
Cubic feet = CBM × 35.315
Packing lists and freight documents often show the total CBM for a shipment. Multiply it by 35.315 and you have your storage volume straight away, before a single carton is measured. It’s the fastest way to estimate the space a full container will need.
Quick conversion reference
Bookmark these four values. They cover almost every conversion you’ll need for storage.
| Unit | Equals |
|---|---|
| 1 CBM | 35.315 cu ft |
| 1 cu ft | 0.0283 CBM |
| 1 cu ft | 28,317 cm³ |
| 1 cu ft | 1,728 in³ |
The table below puts all five starting points side by side, including a standard US pallet, so you can find your unit and go straight to the answer.
Converting carton dimensions to cubic feet
| Your dimensions are in | Formula | Example | Result |
|---|---|---|---|
| Centimeters | (L × W × H) ÷ 28,317 | 60 × 40 × 50 cm | 4.24 cu ft |
| Inches | (L × W × H) ÷ 1,728 | 24 × 16 × 20 in | 4.44 cu ft |
| Meters | L × W × H × 35.315 | 1.2 × 1.0 × 0.8 m | 33.9 cu ft |
| Cubic meters (CBM) | CBM × 35.315 | 2 CBM | 70.6 cu ft |
| Standard US pallet | (48 × 40 × H in) ÷ 1,728 | 48 × 40 × 60 in | 66.7 cu ft |
Cubic feet calculation examples
These five examples cover the situations international brands run into most, from a single carton to a mixed inbound shipment. Each one keeps the full numbers until the end and rounds only the final result. Copy the steps and swap in your own carton sizes.
Example 1: one carton in centimeters
Setup: a carton of 60 × 40 × 50 cm.
- 60 × 40 × 50 = 120,000 cm³
- 120,000 ÷ 28,317 = 4.24
Result: 4.24 cu ft per carton. This is the per-carton figure a warehouse records when your stock arrives. Multiply it by your carton count for the total.
Example 2: an inbound shipment from an overseas supplier
Setup: 200 cartons of 50 × 40 × 30 cm.
- 50 × 40 × 30 = 60,000 cm³ per carton
- 60,000 ÷ 28,317 = 2.119 cu ft per carton
- 2.119 × 200 = 423.8
Result: about 424 cu ft of storage. Send this figure to your warehouse before the stock ships, so it can plan the space and quote your storage cost from day one.
Example 3: a carton in inches
Setup: a carton of 24 × 16 × 20 in.
- 24 × 16 × 20 = 7,680 in³
- 7,680 ÷ 1,728 = 4.44
Result: 4.44 cu ft per carton. If your supplier already works in inches, this is the quickest route, with no metric conversion needed.
Example 4: a packing list in CBM
Setup: the supplier’s packing list shows 6.29 CBM in total.
- 6.29 × 35.315 = 222.1
Result: about 222 cu ft of storage. Use this as an estimate before the stock arrives. The warehouse will confirm the real volume when it measures your cartons on receiving.
Example 5: mixed SKUs
Setup: SKU A is 100 cartons of 40 × 30 × 30 cm. SKU B is 50 cartons of 60 × 40 × 40 cm.
- SKU A: 40 × 30 × 30 = 36,000 cm³ ÷ 28,317 = 1.271 cu ft per carton
- 1.271 × 100 = 127.1 cu ft
- SKU B: 60 × 40 × 40 = 96,000 cm³ ÷ 28,317 = 3.390 cu ft per carton
- 3.390 × 50 = 169.5 cu ft
- 127.1 + 169.5 = 296.6
Result: about 297 cu ft of storage. Working out each SKU separately also shows you which products take up the most space, and cost the most to store.
How carton dimensions affect storage cost
With cubic pricing, every centimeter of empty space in a carton is paid for, every month the carton sits on the shelf.
Why carton size matters
Warehouses measure the outside of the carton. Empty space, extra padding and oversized boxes all count as stored volume, even though they hold nothing you can sell.
The cost repeats. A shipping charge is paid once. Storage is billed every month, so an oversized carton costs you again and again for as long as the stock sits in the warehouse.
Worked example: right-sized vs oversized cartons
Take 1,000 cartons holding the same products, stored at $0.46 per cubic foot per month, the typical US market average reported by Olimp Warehousing. Your own rate will depend on the warehouse and region, so swap in the figure from your quote.
| Oversized carton | Right-sized carton | |
|---|---|---|
| Carton size | 50 × 40 × 30 cm | 45 × 35 × 25 cm |
| Volume per carton | 2.12 cu ft | 1.39 cu ft |
| Volume for 1,000 cartons | 2,119 cu ft | 1,390 cu ft |
| Monthly storage cost | about $975 | about $640 |
- Oversized: 60,000 cm³ ÷ 28,317 × 1,000 = 2,119 cu ft × $0.46 = about $975 a month
- Right-sized: 39,375 cm³ ÷ 28,317 × 1,000 = 1,390 cu ft × $0.46 = about $640 a month
- Difference: about 34% less space and roughly $335 saved every month, or about $4,000 a year
The products are the same. Only the boxes changed. Working with your supplier on right-sized cartons, or switching to branded packaging made to fit your products, is one of the simplest ways to cut storage costs.
How 3PL storage is calculated by actual volume
Many 3PLs that bill by the cubic foot turn the cartons on their shelves into a monthly bill in four steps:
- Measure each SKU’s carton when the stock arrives.
- Add up the cubic feet of everything in stock, every day.
- Average those daily totals over the month.
- Multiply the average by the rate per cubic foot.
How the volume is measured
Carton dimensions on receiving. The warehouse records each SKU’s carton size when your stock arrives. That’s why sending accurate dimensions in advance matters.
Daily stored volume. Each day, the system adds up the cubic feet of everything you have in stock. A good ASTORAGEHUB Platform gives you real-time inventory visibility, so you can watch that number fall as orders ship.
How the monthly bill is worked out
Average volume. The daily totals are added up and divided by the number of days in the month. This is how cubic storage keeps the bill in step with your stock: as products sell, the daily volume drops, and so does what you pay. Some 3PLs skip the daily average and bill on a single count each month, so ask which method a warehouse uses before you sign.
Example. If your stored volume averages 1,200 cu ft over a month, at the $0.46 market average that’s 1,200 × $0.46 = $552 for the month.
What’s billed separately. Receiving, pick and pack, and any minimum monthly fee are usually charged on top, so ask for all of them when you compare quotes. Our pricing page shows how these fees are laid out.
If your stock sits on full pallets for months, pallet pricing may cost less, as our guide Cubic Feet vs Pallet Pricing explains.
Common cubic feet calculation mistakes
Most storage estimates go wrong in one of four ways. Each one is easy to avoid once you know it.
Measuring the product instead of the carton. Your estimate comes out too low, and the warehouse bill is higher than you expected. Always measure the outside of the carton, packaging included, at its widest point.
Mixing centimeters and inches. A carton noted as 60 cm × 40 cm × 16 in gives a meaningless result. Convert all three sides to the same unit before you multiply, and write the unit next to each number.
Using the wrong divisor. Centimeters divide by 28,317 and inches by 1,728. If you divide cubic centimeters by 1,728 by mistake, your result comes out about 16 times too high.
Rounding too early. Rounding each carton’s volume, then multiplying by hundreds of cartons, turns a small error into a big one. Keep the full numbers and round only the final total.
How to lower your storage volume and cost
Your storage bill comes down to two things: how much space your stock takes up, and how long it stays. These four habits shrink both, and you can start on all of them before your next shipment.
Right-size cartons with your supplier. Agree carton sizes before production, not after the stock lands. A carton that fits the product closely sends less empty space to the warehouse, so you stop paying rent on air every month.
Consolidate partial cartons. Half-empty cartons of the same SKU take up as much space as full ones. Combining them reduces your stored volume straight away, and it speeds up picking too, because staff open fewer boxes.
Send accurate carton dimensions before stock arrives. Share each SKU’s carton size and count with your warehouse before the shipment lands. It lets the warehouse plan space and quote correctly from day one. If you ship full containers, ask how container unloading and measuring are handled on arrival.
Clear slow-moving stock. Every month a slow seller sits on the shelf, it adds to your bill, even if it never sells. Use reports from warehouse management systems to spot slow SKUs early, then discount, bundle or remove them.
Need Help With Inventory Storage?
ASTORAGEHUB provides cubic storage, warehousing and fulfillment services for ecommerce and B2B businesses, including international brands.
FAQ – Calculating cubic feet for storage
There are 35.315 cubic feet in one cubic meter (CBM). To convert, multiply your CBM figure by 35.315. For example, a shipment listed as 2 CBM on a packing list takes up about 70.6 cubic feet of storage space in a US warehouse.
Multiply the length, width and height in centimeters, then divide the result by 28,317, the number of cubic centimeters in a cubic foot. A 60 × 40 × 50 cm carton, for example, is 120,000 cubic centimeters, which works out to 4.24 cubic feet.
Multiply the length, width and height in inches, then divide by 1,728, the number of cubic inches in a cubic foot. A 24 × 16 × 20 in carton is 7,680 cubic inches, or 4.44 cubic feet. Multiply by your carton count for the total.
A standard 48 × 40 in pallet loaded 60 in high holds about 66.7 cubic feet. Every foot of height on that footprint adds about 13.33 cubic feet, so the same pallet loaded to 72 in holds about 80 cubic feet.
Most measure the cubic feet you have in stock, either every day or once a month, and multiply by a rate per cubic foot. With daily measuring, the month is averaged, so the bill falls as stock sells. At the US market average of about $0.46, an average of 1,200 cubic feet costs about $552 a month.
Yes. Warehouses measure the outside of each carton, so any empty space or padding inside counts as stored volume. In our worked example, switching 1,000 cartons to a right-sized box cut stored volume by about 34% and saved roughly $335 a month.
Conclusion
Working out cubic feet takes one formula and the right divisor: 28,317 for centimeters, 1,728 for inches, or multiply cubic meters by 35.315. Once you know your total volume, you know what your inventory will cost to store each month, and where you can save. Smaller, well-packed cartons and accurate dimensions sent before stock arrives keep that number low, month after month.
Need Help With Inventory Storage?
ASTORAGEHUB provides cubic storage, warehousing and fulfillment services for ecommerce and B2B businesses, including international brands.
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