Calculate thrust-to-weight ratio from total thrust and mass, or find the missing value and plan single-engine thrust and engine count.

Thrust to Weight Ratio Calculator

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Thrust to Weight Ratio Formula

The following formula is used to calculate the thrust-to-weight ratio. (Weight is a force; if you are given mass, convert it to weight using W = m·g.) 

TWR = T / (m g)
  • Where TWR is the thrust-to-weight ratio (dimensionless)
  • T is the total thrust (N)
  • m is the total mass (kg)
  • g is gravitational acceleration (use standard Earth gravity g ≈ 9.80665 m/s² unless otherwise specified)

To calculate the thrust-to-weight ratio, divide the total thrust by the vehicle’s weight (where weight = mass × g).

How to Calculate Thrust to Weight Ratio?

The following example problems outline how to calculate thrust-to-weight ratio.

Example Problem #1:

  1. First, determine the total thrust (N).
    • The total thrust is given as: 10,000 N.
  2. Next, determine the total mass (kg).
    • The total mass is provided as: 500 kg.
  3. Finally, calculate the thrust-to-weight ratio using the equation above (with g ≈ 9.80665 m/s²). 

TWR = T / (m·g)

The values given above are inserted into the equation below and the solution is calculated:

TWR = 10,000 / (500 × 9.80665) ≈ 2.0394 (dimensionless)

Example Problem #2: 

For this problem, the variables required are provided below:

total thrust (N) = 50,000

total mass (kg) = 2,000

Test your knowledge using the equation and check your answer with the calculator above.

TWR = T / (m·g) = ?