Bag Calculator
Calculate bag capacity and determine optimal packing efficiency
Bag Calculator
Table of Contents
How to Calculate Bag Capacity
Bag capacity calculation involves determining total volume and applying packing efficiency:
- Total Volume = Length × Width × Height
- Usable Volume = Total Volume × Packing Efficiency
- Volume conversions: 1 liter = 61.02 cubic inches
- Packing efficiency varies from 50% (loose) to 90% (compression)
The calculator provides results in both liters and cubic inches, along with capacity classification and recommended uses based on the calculated volume.
Understanding Packing Efficiency
Loose Packing (50%)
Casual packing with irregular items, lots of air gaps. Common with bulky items or when packing quickly.
Normal Packing (65%)
Standard packing with some organization. Most people achieve this efficiency with everyday packing habits.
Tight Packing (80%)
Careful organization, efficient use of space, minimal air gaps. Requires planning and proper item selection.
Compression Packing (90%)
Using compression sacks, packing cubes, and strategic arrangement. Maximum efficiency for extended trips.
Bag Capacity Categories
| Category | Volume (Liters) | Typical Use | Duration |
|---|---|---|---|
| Small Day Pack | < 10L | School, gym, short hikes | Few hours |
| Day Pack | 10-20L | Day hikes, commuting | Full day |
| Large Day Pack | 20-35L | Long hikes, carry-on travel | 1 day |
| Weekend Pack | 35-50L | Overnight trips | 1-2 nights |
| Multi-day Pack | 50-70L | Backpacking trips | 3-5 days |
| Expedition Pack | 70L+ | Extended expeditions | 1+ weeks |
Packing Tips and Techniques
- Use Packing Cubes: Organize items in compression cubes to maximize space and maintain organization
- Roll Don't Fold: Rolling clothes saves 20-30% more space than folding and reduces wrinkles
- Fill Dead Spaces: Use socks, underwear, and small items to fill gaps in shoes and corners
- Heavy Items Bottom: Pack heavy items at the bottom and close to your back for better weight distribution
- Compression Straps: Use internal and external compression straps to reduce bag volume and stabilize load
- Multi-purpose Items: Choose items that serve multiple functions to reduce overall weight and volume
Frequently Asked Questions
Why is actual usable volume less than total volume?
Bag shape, compartments, zippers, and packing methods create dead space. Even with efficient packing, you typically can only use 65-80% of the total volume effectively.
How do I measure my bag accurately?
Measure the main compartment's internal dimensions (length, width, height) at the widest points. Don't include external pockets or protruding parts in the main calculation.
What's the difference between advertised and actual capacity?
Manufacturers often measure total volume including all pockets and spaces. Real-world usable capacity is typically 10-20% less than advertised due to bag construction and packing limitations.
How does bag shape affect capacity?
Rectangular bags use space most efficiently. Tapered, curved, or irregularly shaped bags have more dead space and lower packing efficiency despite similar measured dimensions.