Ensure flight safety and legality with our precise C172 loading tool.
1. Aircraft Basic Empty Weight
Enter the weight from current weight and balance record.
Please enter a valid weight.
Total moment from records (Weight × Arm).
Please enter a valid moment.
2. Load the Aircraft
Arm: 37 inches
Arm: 73 inches
Standard: 53 gal max. Arm: 48 inches. (6 lbs/gal)
Arm: 95 inches (Max 120 lbs)
Arm: 123 inches (Max 50 lbs)
Center of Gravity (CG)
39.5″
Within Limits
Total Gross Weight:1800 lbs
Max Gross Weight:2550 lbs
Total Moment:71000 lb-in
Category:Normal
Formula Used: CG = Total Moment ÷ Total Weight.
Moments are calculated by multiplying the weight of each station by its arm (distance from datum).
Station
Weight (lbs)
Arm (in)
Moment (lb-in)
TOTALS
0
–
0
Figure 1: Center of Gravity Envelope. The blue dot represents your current loading configuration.
What is a Cessna 172 Weight and Balance Calculator?
A cessna 172 weight and balance calculator is a critical pre-flight planning tool used by pilots to ensure their aircraft is loaded within the safety limits specified by the manufacturer. Unlike a car, an aircraft's handling characteristics change drastically depending on how much weight it carries and, more importantly, where that weight is placed.
Every Cessna 172 has a specific Maximum Gross Weight and a permissible Center of Gravity (CG) range. If the plane is too heavy, it may not climb over obstacles. If the CG is too far forward or aft, the pilot may lose control effectiveness, potentially leading to a stall or inability to recover from a spin. This calculator helps pilots quickly input passenger, fuel, and baggage weights to verify the aircraft is safe to fly.
Who should use it? Student pilots, flight instructors, and private pilots operating C172 models (such as the 172N, 172P, 172R, or 172S) should use a weight and balance calculator before every flight.
Cessna 172 Weight and Balance Formula
The mathematical principle behind the cessna 172 weight and balance calculator is the law of the lever. The aircraft balances around its Center of Gravity (CG). To find this point, we calculate the "Moment" for every item loaded.
The Core Formulas:
Moment = Weight × Arm
Total Weight = Sum of all individual weights
Total Moment = Sum of all individual moments
Center of Gravity (CG) = Total Moment ÷ Total Weight
Variable
Meaning
Unit
Typical C172 Range
Weight
Force exerted by gravity on an object
Lbs
0 – 2550 lbs (Total)
Arm
Horizontal distance from the reference datum
Inches
30″ – 130″
Moment
Rotational force (Weight × Arm)
lb-in
50,000 – 120,000
Datum
Imaginary vertical plane (Reference zero)
–
Firewall (usually)
Practical Examples: Real-World Loading Scenarios
Example 1: The "Date Night" (Light Load)
A pilot is taking a friend for a local scenic flight in a Cessna 172S.
Basic Empty Weight: 1650 lbs (Moment: 64,350)
Pilot & Passenger: 340 lbs (Arm: 37″)
Rear Seats: 0 lbs
Fuel: 30 Gallons (180 lbs @ Arm 48″)
Baggage: 10 lbs (Arm: 95″)
Result: The Total Weight is 2180 lbs. The calculated CG is roughly 38.9 inches. This falls well within the "Utility Category" envelope, allowing for limited acrobatic maneuvers like spins (if approved).
Example 2: The "Cross-Country" (Heavy Load)
Four adults are flying to a weekend getaway with luggage.
Basic Empty Weight: 1650 lbs
Front Seats: 380 lbs
Rear Seats: 350 lbs (Arm: 73″)
Fuel: 40 Gallons (240 lbs)
Baggage: 50 lbs
Result: Total Weight approaches 2670 lbs, which exceeds the max gross weight of 2550 lbs for a C172S. The cessna 172 weight and balance calculator would flag this as unsafe. To fly legally, the pilot must reduce fuel or leave baggage behind.
How to Use This Cessna 172 Weight and Balance Calculator
Follow these steps to ensure accurate results:
Get your numbers: Consult the specific Weight and Balance sheet found in Section 6 of your aircraft's POH (Pilot's Operating Handbook). Every plane is unique.
Input Empty Weight: Enter the Basic Empty Weight and Moment from the aircraft documents.
Add Passengers: Enter weights for the front and rear seats. Include clothes and headsets in these weights.
Enter Fuel: Input the gallons of usable fuel. The calculator automatically converts this to pounds (6 lbs/gal).
Add Baggage: Measure baggage weight accurately. Note that Baggage Area 1 and 2 have different arms.
Check the Graph: Look at the blue dot on the chart. If it is inside the polygon, you are within the envelope. If it is outside, the flight is prohibited.
Key Factors That Affect Cessna 172 Loading Results
Understanding what influences your cessna 172 weight and balance calculator results is vital for safety:
Fuel Burn: As you fly, you burn fuel. Since fuel is located at station 48″ (relatively forward compared to baggage), burning fuel usually shifts the CG backward. Always calculate your landing weight and CG as well.
Temperature and Density Altitude: While not part of the W&B calc directly, a heavy plane on a hot day performs significantly worse. A legal weight at sea level might be unsafe at high-altitude airports.
Baggage Placement: Moving 50 lbs from Baggage Area 1 to Area 2 (further aft) increases the moment significantly, moving the CG aft. This destabilizes the aircraft (pitch sensitivity increases).
Installed Equipment: If your C172 has new avionics or wheel fairings installed, the Basic Empty Weight changes. Always use the latest records.
Category Changes: The C172 often has "Normal" and "Utility" categories. Utility category (required for spins) has a much lower max gross weight and a stricter forward CG limit.
Standard Weights vs. Actual Weights: Never assume a passenger weighs 170 lbs. Ask for actual weights or use a scale. Small errors accumulate.
Frequently Asked Questions (FAQ)
What is the datum line in a Cessna 172?
The datum is the imaginary reference line from which all arm measurements are taken. In most Cessna 172 models, the datum is the front face of the firewall.
Why is an aft CG dangerous?
An aft CG (Center of Gravity too far back) makes the aircraft unstable in pitch and difficult to recover from a stall or spin. It also reduces elevator effectiveness.
How much does Avgas weigh?
Standard Aviation Gasoline (100LL) weighs approximately 6 pounds per gallon at standard temperatures. This cessna 172 weight and balance calculator uses this standard conversion.
Can I fly if I am 1 lb over Max Gross Weight?
Legally, no. The Maximum Gross Weight is a limitation set by the FAA and the manufacturer. Flying overweight invalidates your airworthiness certificate.
What is the difference between Normal and Utility category?
Normal category allows for higher gross weights but prohibits certain maneuvers (like spins). Utility category allows for limited acrobatics but restricts weight and CG range to ensure structural integrity.
Does oil count in the empty weight?
Yes, "Basic Empty Weight" typically includes full oil and unusable fuel. However, always check your specific aircraft's equipment list definition.
What happens if I enter the wrong arm?
Entering the wrong arm will result in an incorrect Moment and CG calculation. Always verify the arm stations (e.g., Front Seats = 37″) in your POH.
Does this calculator work for a Cessna 182?
No. While the math is the same, the arms, weights, and CG limits are completely different. You must use a calculator specific to the airframe you are flying.