Weight vs Unit vs Total Allowance Systems: Understanding Airline Baggage Rules

Quick Answer

Airlines use three primary baggage systems: piece (unit) system, weight-based system, and total (linear or combined) allowance system. The piece system limits the number of bags (e.g., 1 or 2 bags up to 23 kg / 50 lb each). The weight system sets a total weight across all bags (e.g., 30 kg / 66 lb total). The total allowance system limits overall dimensions (e.g., 158 cm / 62 linear inches).

• Key takeaway: Always confirm which system your airline uses before packing.
• Key takeaway: International routes may use different systems than domestic routes.

Definitions

Decision Framework

If This → Then Do That

• If your ticket states “1PC 23 kg” → You are under the piece system.
• If it states “30 kg total” → You are under the weight system.
• If it mentions “158 cm / 62 in max dimensions” → Linear allowance applies.

• □ Confirm baggage system on your ticket.
• □ Weigh bags using a digital luggage scale.
• □ Measure total external dimensions including wheels and handles.
• □ Convert units (kg ↔ lb, cm ↔ in) if needed.

How To Identify Your Airline’s System

1. Check your booking confirmation for “PC” (piece) or “kg total.”
2. Visit your airline’s baggage policy page.
3. Use the LuggaGenius baggage comparison tool to compare allowances by airline and fare.

Industry Shift: Why Systems Are Changing

Historically, North American airlines favored the piece system, while many European and Asian carriers used weight-based systems. Today, more airlines are adopting hybrid approaches combining:

The shift toward hybrid models allows airlines to:

• Standardize global routes
• Optimize cargo revenue
• Reduce handling inefficiencies
• Introduce dynamic baggage pricing

Always verify exact rules per airline because enforcement varies by aircraft, route, and region.

What Varies by Airline

Policies differ significantly. For example:

• Iberia baggage policy (Compare other airlines)
• Vueling baggage policy (Compare other airlines)
• Singapore Airlines baggage policy (Compare other airlines)

Low-Cost vs Flag Carrier Comparison

Recommended Tools

Digital Luggage Scales

Budget Pick: Etekcity Digital Luggage Scale – Lightweight and simple, ideal for occasional travelers.

Premium Pick: Dr.meter Digital Scale – Higher precision sensor, better grip handle, reliable for frequent flyers.

Common Mistakes

• Assuming “2 bags” means unlimited weight.
• Ignoring total linear size limits (158 cm / 62 in).
• Mixing unit systems across connecting flights.
• Failing to convert kg to lb properly.
• Not accounting for wheel and handle dimensions.

FAQ

What does 1PC mean on my ticket?

It means one checked bag under the piece system, usually capped at 23 kg (50 lb) in economy.

Is 158 cm the same as 62 inches?

Yes. 158 cm equals approximately 62 linear inches.

Can airlines combine weight across bags?

Only under weight-based systems. Under the piece system, each bag must meet individual limits.

Are international flights more generous?

Often yes, especially in premium cabins, but this varies by airline and route.

Do business class passengers get higher limits?

Typically yes — often 2 x 32 kg (70 lb each), depending on airline.

Update Note

Last reviewed and updated: 2026-02-13