Shock Length Calculator
In both cases you are car enthusiast or a mechanic and want to finetune your vehicle’s suspension system, Use this Shock Length Calculator. Just enter Distance between upper and lower shock mount (in), Distance between bump stop and axle (in), in the input fields of the calculator and the calculator will display Collapsed Shock Length (in) and Extended Shock Length (in) of your car.
What Is Shock Length?
Shock length is the distance between the mounting points of the shock absorber. This length plays a vital role in maintaining the suspension performance of the vehicle and enabling the shocks to absorb impact.
User Guide
The Shock Length Calculator comes in two modes: Basic and Advanced, you switch which one is better for your requirements.
1. Basic Mode
In the Basic Calculator, simply input the distance between the upper and lower shock mounts, along with the distance between the bump stop and the axle. The calculator will then determine the collapsed shock length and the extended shock length based on your inputs.
2. Advanced Mode
For more precise adjustments, you can switch to the Advanced Calculator. Here, you can enter the total suspension travel, ride height adjustment, and the minimum shock length. The calculator will compute the adjusted collapsed and extended lengths, taking into account your specific requirements.
Example Input Values:
 Distance between upper and lower shock mounts (D1): 12 inches
 Distance between bump stop and axle (D2): 4 inches
Formula Used
The formula to calculate the shock length is:
$\text{SHOCK} = (D1 – D2) – 1$
Where:
Variable  Description 

SHOCK  Shock Length (inches) 
D1  Distance between upper shock mount and lower shock mount (inches) 
D2  Distance between bump stop and axle (inches) 
How to Calculate Shock Length
1. Measure D1: Distance between the upper shock mount and lower shock mount.
2. Measure D2: Distance between the bump stop and the axle.
3. Apply the Formula:

 Subtract D2 from D1.
 Subtract 1 from the result.
Calculation:
 D1: 12 inches
 D2: 4 inches
$\text{SHOCK} = (12 – 4) – 1 = 7 \text{ inches}$
Calculation Examples
1. Basic
Measurement  Value 

Distance between upper and lower shock mounts (D1)  12 inches 
Distance between bump stop and axle (D2)  4 inches 
Calculated Shock Length (SHOCK)  7 inches 
2. Advanced
Measurement  Value 

Distance between upper and lower shock mounts (D1)  15 inches 
Distance between bump stop and axle (D2)  6 inches 
Calculated Shock Length (SHOCK)  8 inches 
Shock absorber Length Chart
Lift Height (in)  Collapsed Length (in)  Extended Length (in) 

0  12.5  20 
2  14.5  22 
4  16.5  24 
6  18.5  26 
8  20.5  28 
10  22.5  30 
Importance & Benefits
Importance  Benefits 

Ensures proper suspension performance  Improves ride comfort 
Enhances vehicle stability  Reduces wear and tear on tires 
Prevents bottoming out  Increases safety 
Customizes suspension setup  Adapts to different terrains 
Matches shock length to lift height  Optimizes offroad capability 
FAQs
How to Choose the Correct Shock Size
Choosing the right shock size means measuring the frame of the vehicle at the mount locations and considering what the vehicle will be used for. Use the Shock Length Calculator to find the correct size.
What Size Shocks Do I Need for a 6 Inch Lift?
For a 6inch lift, you’ll need longer shocks to match the extra length. Measure the new distance between the shock mounts after your lift, then use the calculator to find the proper shock length.
What Shocks Do I Need for a 3Inch Lift?
For a 3inch lift, measure from shock mount to shock mount after the lift. Plug these numbers into the calculator, and it will give you the proper shock size.
Using shock length calculator you surely adjust car shock length. In case you require any kind of additional information regarding this tool you can ask me in the comment section.