In case you've never gotten along with millimeters, or in case you need to do some conversions and never got along with algebra, this page contains easy conversions back and forth between inches and millimeters.
Sections on this page:
- Easy estimates, without a calculator
Inch-to-Millimeter
Millimeter-to-Inch - How to make Exact Conversions, with a calculator
Inch-to-Millimeter
Millimeter-to-Inch - Other miscellaneous conversion units
If you have inches, and want to know how many millimeters:
- Step one: Convert any inch fractions to decimals.
Example: 1/4 inch = 1 divided by 4 = 0.25 inch
Example: 1/16 inch = 1 divided by 16 = 0.0625 inch- For amounts over an inch, you want to first convert the fractional part, then add the whole inches part:
Example: 1-5/8 inch = 5 divided by 8, then plus 1 = 1.625 inch - Step two:Multiply that decimal by 25.4
For each of the above examples, the complete steps would be:
1/4 inch = 1 divided by 4, x 25.4 = 6.35mm (6mm)
1/16 inch = 1 divided by 16, x 25.4 = 1.5875 (1.6mm)
2-1/4 inch = 1 divided by 4, plus 2, x 25.4 = 57.15 (57mm)
1-5/8 inch = 5 divided by 8, plus 1, x 25.4 = 41.275 (41mm)
If you have millimeters (or centimeters), and you want inches:
- Step one: Divide your millimeter amount by 25.4
(or divide your centimeter amount by 2.54)
Example 1: 2mm divided by 25.4 = .07874 inches
Example 2: 6mm divided by 25.4 = .2362 inches
Example 3: 30mm divided by 25.4 = 1.1811 inches
Example 4: 4cm divided by 2.54 = 1.5748 inches
So, 20 inches (per necklace) divided by .2362 inches (per bead) = 84.67 beads per necklace.
Since you probably need to reserve a bit of space for your bead tips and a clasp, I would round down to 80 beads. Number of beads per strand chart
If, however, you want fractions of an inch (1/16, 1/4, 1/2), rather than a decimal, try this:
- Step two: Converting your decimal to a useable fraction:
I prefer to round to the nearest 1/16 of an inch. To round to the nearest 1/16 of an inch, multiply your decimal by 16. The resulting number is how many 1/16's of an inch you have.Using the numbers from Step 1 above:
.07874 times 16 = 1.26, which rounds to 1, so about 1/16 inch.
.2362 times 16 = 3.779, which rounds to 4, so about 4/16. 4/16 = 1/4 inch- For amounts over an inch, it is easiest to remove the whole inches, and add them back in after you convert the portion after the decimal point:
1.5748 Removing the 1 gives you .5748 times 16 = 9.1968, which rounds to 9, so about 9/16 inch... don't forget to add the 1 back on, so this is really 1-9/16 inch.
Using the numbers from step 1, that I also used in step 2, you would get...
.07874 times 4 = .315, which rounds to 0, so you get 0/4 of an inch (not a very useful number!)
.2362 times 4 = .9448, which rounds to 1, so you get 1/4 of an inch (which happens to be accurate)
- inches to millimeters, multiply by 25.4
- inches to centimeters, multiply by 2.54
- millimeters to inches, divide by 25.4
- centimeters to inches, divide by 2.54
- meters to feet, multiply by 3.28
- feet to meters, divide by 3.28
- millimeters to centimeters, divide by 10
- centimeters to meters, divide by 100
As an expert in measurements and conversions, it's essential to delve into the intricacies of units like millimeters and inches, especially in the context of jewelry making. The provided article highlights the significance of millimeters in precision work and offers practical conversions between inches and millimeters for jewelry components.
Let's break down the key concepts discussed in the article:
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Importance of Millimeters in Jewelry Measurements:
- The article emphasizes the suitability of millimeters for measuring small jewelry parts due to their precision.
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Sizes of Gluing Surfaces on Flat Pad Posts:
- The gluing surfaces on flat pad posts are specified in millimeters: 3mm, 4mm, 6mm, 8mm, and 10mm.
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Comparison with Inches:
- The article illustrates the clarity of millimeter sizes compared to inch fractions, emphasizing the ease of understanding millimeters in jewelry measurements.
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Conversion Between Inches and Millimeters:
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The article provides a detailed guide on converting measurements between inches and millimeters, covering both directions.
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For converting inches to millimeters:
- Convert any inch fractions to decimals.
- Multiply the decimal by 25.4 to get the equivalent in millimeters.
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For converting millimeters to inches:
- Divide the millimeter amount by 25.4.
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Decimal to Fraction Conversion:
- The article introduces a method for converting decimals to fractions, particularly rounding to the nearest 1/16 of an inch for jewelry purposes.
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Example of Bead Count Calculation:
- A practical example is provided, demonstrating how to calculate the number of 6mm beads needed for a 20" necklace based on the decimal value.
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Fractional Inch Representation:
- The article guides on converting decimals to fractions, particularly to the nearest 1/16 of an inch for precise jewelry measurements.
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Additional Conversion Units:
- The article covers miscellaneous conversion units, providing a comprehensive guide for jewelers.
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Recommendation on Rounding:
- There's a recommendation against rounding to larger fractions for jewelry purposes, suggesting the use of smaller fractions for more accuracy.
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General Conversion Formulas:
- The article concludes with general conversion formulas for inches to millimeters, inches to centimeters, millimeters to inches, centimeters to inches, meters to feet, feet to meters, millimeters to centimeters, and centimeters to meters.
In summary, the article serves as a valuable resource for individuals involved in jewelry making, offering practical guidance on measurements, conversions, and precision in working with millimeters and inches.
