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Bag Capacity and Liter Converter

Bag Volume Calculator

Calculate bag volume from length, width, and depth. Use it for backpacks, luggage, duffels, flat bags, gusseted bags, and pouches, then convert the estimate to liters, cubic inches, and cubic feet.

Backpacks, Luggage, Pouches, and Bags

Calculate Bag Capacity From Measurements

Enter length, width, and depth to estimate usable bag volume in liters, cubic inches, cubic feet, and cubic centimeters.

Common Starting Points
%
Usable Fill slider
10100%
in
Bag Height slider
180 in
in
Bag Width slider
160 in
in
Bag Depth slider
0.540 in
Measurement tip: use outside dimensions for a quick estimate. If the bag is tapered, padded, or rounded, lower the usable fill to avoid overstating real capacity.

How to Calculate Bag Volume

The basic bag volume formula is length x width x depth. For a rigid box or suitcase, that gives a close outside-volume estimate. For backpacks, duffels, and soft bags, reduce the result with a shape factor because curves, padding, pockets, and seams reduce usable capacity.

Bag Volume Formula by Bag Type

Box Shape or Luggage

Length x width x depth. Best for structured bags and suitcases.

Backpack or Duffel

Length x width x depth x soft-bag factor. Better for rounded and padded bags.

Flat Bag

Length x width x depth x reduced fill factor. Useful for mailers, totes, and flexible bags.

Gusseted Bag or Pouch

Length x width x gusset/depth x fill factor. Useful for pouches and expandable bags.

Bag Volume Size Guide

Volume
Common Bag Type
Typical Use
Under 10 L
Small pouch, sling, or crossbody
Keys, wallet, compact daily carry
10-20 L
Small day bag
School, commuting, light day trips
20-30 L
Everyday backpack
Laptop, gym items, one-day travel
35-45 L
Travel backpack or carry-on range
Weekend travel and carry-on packing
50-70 L
Large duffel or travel bag
Longer trips or bulky gear
75 L+
Expedition or bulk bag
Outdoor gear, storage, oversized loads

Backpack Volume Calculator

Backpack capacity is usually advertised in liters, but outside dimensions can overstate the true packed space. Laptop sleeves, back padding, frames, curved panels, and separate pockets all reduce the main usable volume.

Luggage and Duffel Bag Volume

Structured luggage is closer to a rectangular box, so length x width x depth is usually a better estimate. Duffel bags are rounded and flexible, so a reduced soft-bag factor is more realistic than using the full box volume.

Liters, Cubic Inches, and Cubic Feet Conversion

One cubic inch equals 0.0163871 liters. One cubic foot equals 1,728 cubic inches. These conversions help compare backpack liters, luggage dimensions, storage bag volume, and bulk bag capacity in the same units.

Frequently Asked Questions

How Do I Calculate the Volume of a Bag?+

Measure length, width, and depth, then multiply them together. Convert cubic inches to liters by multiplying by 0.0163871. Soft bags need a shape factor.

How Do You Calculate the Volume of a Backpack?+

Use outside height, width, and depth, then multiply by a soft-bag factor because padding, curves, pockets, and seams reduce usable internal space.

How to Calculate Volume of Luggage Bag?+

For structured luggage, multiply length x width x depth. Convert cubic inches to liters. Reduce the result slightly if wheels, handles, or dividers take space.

Why Is Real Bag Capacity Different From Length x Width x Height?+

Real capacity changes because bags are rounded, tapered, padded, divided, or measured by different brand methods. Treat calculated liters as a practical estimate.