Calculate depth, diameter, or depth-to-diameter ratio from any two values and convert between mm, cm, m, in, and ft using millimeters as the base.
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Depth To Diameter Ratio Formula
The depth to diameter ratio compares a depth measurement to a diameter measurement. The ratio is unitless, but depth and diameter must be in the same unit before dividing.
- R = depth to diameter ratio
- D_p = depth
- D_i = diameter
If you know the ratio and diameter, the calculator rearranges the formula to find depth:
If you know the depth and ratio, the calculator rearranges the formula to find diameter:
The calculator accepts depth and diameter in millimeters, centimeters, meters, inches, or feet. It converts both length values to a common base unit before calculating the ratio, then converts the missing length value back to the unit you selected.
- To calculate ratio: enter depth and diameter. The result is depth divided by diameter.
- To calculate depth: enter diameter and ratio. The result is ratio multiplied by diameter.
- To calculate diameter: enter depth and ratio. The result is depth divided by ratio.
Depth to Diameter Ratio Reference Values
| Depth to Diameter Ratio | Meaning | Example |
|---|---|---|
| 0.25 | Depth is one quarter of the diameter | 25 mm deep, 100 mm diameter |
| 0.50 | Depth is half the diameter | 50 mm deep, 100 mm diameter |
| 1.00 | Depth equals diameter | 100 mm deep, 100 mm diameter |
| 2.00 | Depth is twice the diameter | 200 mm deep, 100 mm diameter |
| 5.00 | Depth is five times the diameter | 500 mm deep, 100 mm diameter |
Length Unit Conversions Used
| Unit | Equivalent in Millimeters |
|---|---|
| 1 mm | 1 mm |
| 1 cm | 10 mm |
| 1 m | 1000 mm |
| 1 in | 25.4 mm |
| 1 ft | 304.8 mm |
Example Calculations
Example 1: Calculate the depth to diameter ratio
You have a depth of 75 mm and a diameter of 25 mm.
The depth to diameter ratio is 3. The depth is 3 times the diameter.
Example 2: Calculate the depth
You have a diameter of 4 in and a depth to diameter ratio of 2.5.
The depth is 10 in.
FAQs
Is the depth to diameter ratio unitless?
Yes. The ratio is unitless because it divides one length by another length. For a correct result, depth and diameter must be converted to the same unit before division.
Can depth and diameter use different units?
Yes. You can enter depth and diameter in different supported units, such as inches and millimeters. The calculator converts both measurements to millimeters internally before calculating the ratio or missing value.
What does a depth to diameter ratio greater than 1 mean?
A ratio greater than 1 means the depth is larger than the diameter. For example, a ratio of 4 means the depth is 4 times the diameter.
