4 millimeters is approximately equal to 0.1575 inches, which can be expressed as the fraction 5/32 inches.
Table of Contents
To convert 4 mm to fraction, first convert millimeters to inches by dividing by 25.4 (since 1 inch = 25.4 mm). Then, approximate the decimal inch value to a common fraction. For 4 mm, this gives about 0.1575 inches, close to 5/32 inches.
Conversion Tool
Result in fraction:
Conversion Formula
The conversion from millimeters to fraction involves two steps. First, convert millimeters to inches by dividing the millimeter value by 25.4, because 1 inch equals exactly 25.4 millimeters. Then, approximate the decimal inches into a fraction, often in terms of 1/16 or 1/32 inches, for easier practical use.
Formula:
Inches = Millimeters ÷ 25.4
Example: Convert 4 mm to inches
Step 1: 4 ÷ 25.4 = 0.1575 inches
Step 2: Approximate 0.1575 as a fraction. Since 0.15625 = 5/32, we round close to 5/32 inches.
Conversion Example
- Convert 10 mm to fraction inches:
- Divide 10 by 25.4: 10 ÷ 25.4 = 0.3937 inches.
- Approximate 0.3937 to fraction: 0.375 (3/8) or 0.40625 (13/32). 0.3937 is closer to 25/64 (0.3906) or 13/32 (0.40625). So, 10 mm ≈ 25/64 inches.
- Convert 15 mm:
- 15 ÷ 25.4 = 0.5906 inches.
- Approximate to fraction: 0.59375 = 19/32 inches, close enough.
- Convert 7 mm:
- 7 ÷ 25.4 = 0.2756 inches.
- Nearest fraction is 9/32 = 0.28125, so 7 mm ≈ 9/32 inches.
- Convert 20 mm:
- 20 ÷ 25.4 = 0.7874 inches.
- Closest fraction is 25/32 = 0.78125 inches.
Conversion Chart
| Millimeters (mm) | Inches (decimal) | Fraction (approx.) |
|---|---|---|
| -21.0 | -0.8268 | -13/16 |
| -20.0 | -0.7874 | -25/32 |
| -19.0 | -0.7480 | -3/4 |
| -18.0 | -0.7087 | -11/16 |
| -17.0 | -0.6693 | -21/32 |
| -16.0 | -0.6299 | -5/8 |
| -15.0 | -0.5906 | -19/32 |
| -14.0 | -0.5512 | -9/16 |
| -13.0 | -0.5118 | -1/2 |
| -12.0 | -0.4724 | -15/32 |
| -11.0 | -0.4331 | -13/32 |
| -10.0 | -0.3937 | -25/64 |
| -9.0 | -0.3543 | -11/32 |
| -8.0 | -0.3149 | -5/16 |
| -7.0 | -0.2756 | -9/32 |
| -6.0 | -0.2362 | -7/32 |
| -5.0 | -0.1969 | -3/16 |
| -4.0 | -0.1575 | -5/32 |
| -3.0 | -0.1181 | -3/32 |
| -2.0 | -0.0787 | -1/16 |
| -1.0 | -0.0394 | -1/32 |
| 0.0 | 0.0000 | 0 |
| 1.0 | 0.0394 | 1/32 |
| 2.0 | 0.0787 | 1/16 |
| 3.0 | 0.1181 | 3/32 |
| 4.0 | 0.1575 | 5/32 |
| 5.0 | 0.1969 | 3/16 |
| 6.0 | 0.2362 | 7/32 |
| 7.0 | 0.2756 | 9/32 |
| 8.0 | 0.3149 | 5/16 |
| 9.0 | 0.3543 | 11/32 |
| 10.0 | 0.3937 | 25/64 |
| 11.0 | 0.4331 | 13/32 |
| 12.0 | 0.4724 | 15/32 |
| 13.0 | 0.5118 | 1/2 |
| 14.0 | 0.5512 | 9/16 |
| 15.0 | 0.5906 | 19/32 |
| 16.0 | 0.6299 | 5/8 |
| 17.0 | 0.6693 | 21/32 |
| 18.0 | 0.7087 | 11/16 |
| 19.0 | 0.7480 | 3/4 |
| 20.0 | 0.7874 | 25/32 |
| 21.0 | 0.8268 | 13/16 |
| 22.0 | 0.8661 | 7/8 |
| 23.0 | 0.9055 | 29/32 |
| 24.0 | 0.9449 | 15/16 |
| 25.0 | 0.9843 | 31/32 |
| 26.0 | 1.0236 | 1 1/32 |
| 27.0 | 1.0630 | 1 1/16 |
| 28.0 | 1.1024 | 1 3/32 |
| 29.0 | 1.1417 | 1 1/8 |
This chart shows millimeter values between -21 and 29 converted to inches in decimal and approximated fractions. Use it for quick reference when converting mm to inches fractions without calculator. Negative values indicate measurements below zero.
Related Conversion Questions
- How do I convert 4 mm exactly into inches in fraction form?
- What fraction of an inch equals 4 millimeters?
- Is 4 mm closer to 1/8 or 1/16 inch fraction?
- How to write 4 mm as a fraction in inches for woodworking?
- What is the simplest fraction equivalent to 4 millimeters in inches?
- Can 4 mm be converted to a standard inch fraction used in sewing?
- Which inch fraction best represents 4 millimeters?
Conversion Definitions
mm: Millimeter is a metric unit of length equal to one thousandth of a meter. It is used to measure small distances or thicknesses in science, engineering, and everyday life. One millimeter equals 0.03937 inches exactly.
fraction: A fraction expresses a part of a whole number, shown as a numerator over a denominator. In measurements, fractions like 1/2 or 5/32 represent portions of an inch, allowing precise expression of lengths smaller than a full unit.
Conversion FAQs
Why do we divide millimeters by 25.4 to get inches?
Division by 25.4 converts millimeters to inches because there are exactly 25.4 millimeters in one inch. This relationship is internationally standard, so dividing by 25.4 converts length units between metric and imperial systems accurately.
How accurate is converting mm to fraction inches?
The conversion to decimal inches is exact, but approximating to fractions introduces small rounding errors. Fractions like 1/16 or 1/32 inch are common increments, so some values won’t match perfectly but can be rounded to the closest fraction for practical use.
Can negative millimeter values be converted to fractions?
Yes, negative millimeter values convert to negative inch fractions, reflecting measurements below zero or in opposite directions. The same conversion formula applies, but the result will be negative, indicating direction or relative position.
Is there a quick way to estimate mm to fractions without a calculator?
You can roughly estimate by remembering 1 mm ≈ 1/25 inch, then use fractions close to that, like 1/32 inch is about 0.79 mm. For example, 4 mm is near 5/32 inch (0.15625). This method gives a fast, though approximate, conversion.
Why use fractions instead of decimal inches in some fields?
Fractions are traditional in fields like carpentry and machining where tools and rulers are marked in fractions. They provide intuitive measurements on standard tools, while decimals require conversion. Fractions also simplify communication among professionals used to imperial units.