Select total dB change, dB per length or total length, then enter the displayed values. Inches, feet, meters, dB/in, dB/ft and dB/m are supported.

Multiply a constant rate by the length.

Constant signed level change per length. Positive means gain; negative means loss. A positive attenuation magnitude uses the opposite sign.

Related Calculators

dB Per Inch Formula

The calculator uses a constant signed level change per length. Positive change means gain and negative change means loss; a positive manufacturer attenuation magnitude has the opposite sign. The base calculation uses inches and dB/in.

Total dB = Length ร— dB / in

To solve for dB per inch:

dB / in = Total dB / Length

To solve for total length:

Length = Total dB / dB / in
  • Total dB is the total gain or loss over the full length, measured in decibels.
  • Length is the total distance over which the dB change occurs. The calculator accepts inches, feet, or meters.
  • dB/in is the decibel change per inch. The calculator also accepts dB/ft and dB/m, then converts them internally.

If you enter total length and dB per inch, the calculator multiplies them to find total dB. If you enter total dB and length, it divides total dB by length to find the dB per inch. If you enter total dB and dB per inch, it divides total dB by the rate to find the required length.

Length and dB Rate Unit Conversions

These conversions show how the calculator standardizes inputs before solving the missing value.

Unit Equivalent in Inches Use in Calculator
1 inch 1 in Base length unit
1 foot 12 in Converted to inches before calculation
1 meter approximately 39.37007874 in Converted to inches before calculation

Rate Unit Equivalent dB/in Example
dB/in Same value 0.5 dB/in = 0.5 dB/in
dB/ft Divide by 12 6 dB/ft = 0.5 dB/in
dB/m Multiply by 0.0254 exactly 19.68503937 dB/m โ‰ˆ 0.5 dB/in

Example Calculations

Example 1: Find total dB

You have a length of 24 inches and a rate of 0.25 dB/in.

Total dB = 24 ร— 0.25 = 6

The total dB is 6 dB.

Example 2: Find dB per inch

You have a total change of 10 dB over 5 feet.

First convert 5 feet to inches:

5 ft ร— 12 = 60 in

Then divide total dB by length:

dB / in = 10 / 60 = 0.1667

The rate is 0.1667 dB/in.

FAQ

What does dB per inch mean?

dB per inch means the decibel change for each inch of length. It is commonly used when a signal, sound level, or other measured quantity changes at a steady rate over distance. For example, 0.2 dB/in means the total change increases or decreases by 0.2 dB for every inch.

Can the dB per inch value be negative?

Yes. A negative value can represent loss, reduction, or attenuation over length. A positive value can represent gain or increase. The formula works the same way, but the sign of the result tells you the direction of the change.

Which values do I enter?

Select the value to solve and enter the displayed inputs. Length must be nonnegative. A zero denominator cannot determine a unique rate or length. Rate and total change must have compatible signs for a nonnegative length.