Convert Length from Us Survey Foot to Micrometer (ft-us to μm)

US Survey Foot to Micrometer Conversion Formula

To convert from US Survey Foot (ft-us) to Micrometer (μm), use the following formula:

With $\frac{1}{3.28084}$ is the ratio between the base units Meter (m) and Foot (ft).

Example

Let's convert 5 US Survey Foot (ft-us) to Micrometer (μm).

Using the formula:

Therefore, 5 US Survey Foot (ft-us) is equal to $1524002.9992319040246$ Micrometer (μm).

What is a US Survey Foot (ft-us)?

The US Survey Foot is a unit of length historically used for land surveying in the United States.

It is very close in length to the international foot, equaling approximately 1.000002 international feet (ft). The plural form is US Survey Feet.

Where Did the US Survey Foot Come From?

The origin of the US Survey Foot dates back to the Mendenhall Order of 1893. This order defined the relationship between the meter and US customary units.

It established that 1 meter is precisely equal to 39.37 inches. From this relationship, the US Survey Foot was derived, defined as 1200/3937 meters.

This definition differs slightly from the international foot, which was established in 1959 and is defined as exactly 0.3048 meters.

Why Was the US Survey Foot Replaced?

To simplify measurements and prevent confusion, the National Institute of Standards and Technology (NIST) and the National Geodetic Survey (NGS) made a critical change.

They officially retired the U.S. Survey Foot on December 31, 2022.

Surveying and mapping applications in the United States will now use the international foot. This critical change helps unify the National Spatial Reference System (NSRS) and prevents costly errors in large-scale projects.

Why Did This Small Difference Cause Big Problems?

While the difference between a US Survey Foot and an international foot is minuscule—only about two parts per million—it becomes significant over large distances.

For every mile, the discrepancy adds up to approximately 1/8 inch.

This minor error may not be significant for a backyard fence. However, for massive construction projects and infrastructure development, such as bridges that cross state lines, the accumulated error can lead to severe misalignments and costly mistakes.

What is a Micrometer (μm)?

A micrometer (μm), commonly referred to as a micron, is a unit of length in the metric system.

It is extremely small, equal to one millionth of a meter (10⁻⁶ m).

Where Are Micrometers Used?

The micrometer may be tiny, but it's indispensable wherever extreme precision is required. Here are some examples of how it's used across different industries:

• Electronics manufacturing: Parts like transistors, traces, and other microchip features are measured in micrometers. Modern CPUs and memory chips depend on manufacturing at these microscopic scales.

• Aerospace engineering: Components are machined to micrometer tolerances, ensuring they fit and perform reliably under extreme stress and temperature conditions.

• Medical devices: Stents, catheters, and many surgical tools must be produced with micrometer-level accuracy to ensure patient safety and proper function.

• Textiles: Fiber diameters—such as wool, silk, and synthetic fibers—are measured in micrometers to assess softness, strength, and the best uses for each material.

Small unit, significant impact: micrometer-level precision underpins quality, safety, and performance across many fields.

How Small Is a Micron? A Size Comparison

It can be hard to grasp just how small a micrometer is.

To put this micrometer size comparison into perspective, consider these examples:

• The average human hair is about 50 to 100 micrometers thick.
• A single red blood cell is typically 7 to 8 micrometers wide.
• A particle of baker's yeast is about 5 micrometers across.

These comparisons highlight the incredible microscopic scale the micrometer represents, far smaller than anything the naked eye can perceive.

Is a Micron the Same as a Micrometer?

Yes, they are the same.

The official name for this unit in the International System of Units (SI) is the micrometer; however, it is often still referred to by its older name, the micron.

The term "micron" was officially retired in 1967 to standardize terminology and prevent confusion. Nonetheless, it remains commonly used in various industries and scientific contexts due to habit.

Therefore, when you encounter a measurement in microns, it is equivalent to a micrometer (1×10⁻⁶ meters).

What is the imperial system?

What is the metric system?

US Survey Foot to Micrometer Conversion Table

Here are some quick reference conversions from US Survey Foot (ft-us) to Micrometer (μm):