Span to Bolt Converter
Convert spans to bolts with our free online length converter.
Quick Answer
1 Span = 0.0075 bolts
Formula: Span × conversion factor = Bolt
Use the calculator below for instant, accurate conversions.
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All conversion formulas on UnitsConverter.io have been verified against NIST (National Institute of Standards and Technology) guidelines and international SI standards. Our calculations are accurate to 10 decimal places for standard conversions and use arbitrary precision arithmetic for astronomical units.
Span to Bolt Calculator
How to Use the Span to Bolt Calculator:
- Enter the value you want to convert in the 'From' field (Span).
- The converted value in Bolt will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Length category.
- Click the swap button (⇌) to reverse the conversion direction.
How to Convert Span to Bolt: Step-by-Step Guide
Converting Span to Bolt involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Span = 0.0075 boltsExample Calculation:
Convert 10 spans: 10 × 0.0075 = 0.075 bolts
Disclaimer: For Reference Only
These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.
Not for professional use. Results should be verified before use in any critical application. View our Terms of Service for more information.
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View all Length conversions →What is a Span and a Bolt?
The Span is an ancient unit of length based on the distance across an outstretched human hand, measured from the tip of the thumb to the tip of the little finger (or sometimes the index finger). As an anthropomorphic unit, its length was inherently variable, depending on the size of an individual's hand.
Historically, it was often defined in relation to other body-based units:
- Typically considered half a cubit.
- Often equated to 3 palms (where a palm is the width of the hand across the base of the fingers).
- Sometimes defined as 12 digits (fingerbreadths).
A common, though unofficial, modern estimate for a span is around 9 inches or approximately 22.86 centimeters (cm).
A Bolt is a commercial unit of length primarily used for measuring rolls of cloth or fabric. Unlike standardized units like the meter or yard, the length of a bolt is not fixed and can vary significantly depending on the type of material, the manufacturer, the country of origin, and trade customs.
Common lengths often associated with a bolt include:
- 40 yards (approximately 36.58 meters) - Frequently cited, especially for cottons and silks in the US.
- 100 yards (approximately 91.44 meters) - Often used for heavier fabrics like canvas.
- Other lengths such as 30, 50, 60, or 120 yards may also be encountered.
The bolt represents a quantity convenient for wholesale trade, manufacturing, and inventory management rather than a precise scientific measurement.
Note: The Span is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Bolt belongs to the imperial/US customary system.
History of the Span and Bolt
The span is one of the oldest informal units of measurement, used by numerous ancient civilizations, including the Egyptians, Israelites, Greeks, and Romans, due to the convenience of using the human hand.
- Ancient Egypt & Mesopotamia: The span was used alongside the cubit and digit. The relationship (often 1 span = 1/2 cubit) was fundamental in their systems.
- Biblical References: The span is mentioned in the Bible (e.g., Exodus 28:16 describing the High Priest's breastplate, Goliath's height in some interpretations).
- Ancient Greece & Rome: Used as a practical subdivision of the cubit.
- Medieval Europe: Continued in informal use and sometimes appeared in texts defining lengths. In England, it was often standardized (unofficially) as 9 inches.
Like other anthropomorphic units, the span fell out of official use with the development and adoption of more standardized systems like the Imperial (inches, feet) and Metric (meters) systems, which provided necessary precision for trade, science, and industry.
The concept of the bolt emerged from the practical needs of the textile industry. As cloth production scaled up, manufacturers and merchants needed a standardized way to handle, store, and trade large quantities of fabric. Winding cloth onto a roll or board (the "bolt") provided a convenient package.
The length associated with a bolt likely developed through trade customs specific to different types of fabric and regions. There was never a universal legal standard defining its length, leading to the wide variations seen historically and currently. While retail sales shifted towards measurement by the yard or meter, the bolt remained a useful unit in wholesale and industrial contexts. Even with the global adoption of the metric system, the term "bolt" persists in the textile trade as a reference to a full roll of fabric, though the exact length is usually specified separately in yards or meters.
Common Uses and Applications: spans vs bolts
Explore the typical applications for both Span (imperial/US) and Bolt (imperial/US) to understand their common contexts.
Common Uses for spans
The span is now obsolete for precise or official measurements but is still encountered or used in specific contexts:
- Informal Estimation: Used for quick, rough measurements of moderate lengths where precision is not critical (e.g., gardening, crafts, estimating object sizes).
- Historical Texts: Found in ancient and medieval documents, requiring understanding for interpretation.
- Anthropology & Archaeology: Relevant when studying historical measurement systems or interpreting dimensions from ancient sites.
- Figurative Language: Can be used metaphorically to denote a small distance or extent ("life span").
- Understanding Historical Units: Key to grasping the relationship between units like the digit, palm, and cubit in ancient systems.
When to Use bolts
The bolt is almost exclusively used within the textile industry:
- Wholesale Trade: Fabric manufacturers sell cloth to distributors or large buyers in bolts.
- Manufacturing: Clothing and upholstery manufacturers purchase fabric by the bolt for production runs.
- Inventory Management: Textile mills, warehouses, and large retailers manage stock using bolts as units.
- Industrial Fabrics: Suppliers of canvas, vinyl, and other industrial textiles often sell material by the bolt.
It is generally not used for retail sales to consumers, where fabric is typically measured and cut to specific lengths (yards or meters) from the bolt.
Additional Unit Information
About Span (span)
How long is a span?
There is no single, universally fixed length for a span because it's based on human hand size. However:
- A common historical and modern estimate is 9 inches (in).
- This is approximately 22.86 centimeters (cm) or 0.2286 meters (m).
- Historically, it was often defined as half a cubit, which varied (e.g., a common cubit of ~18 inches would yield a 9-inch span).
What is the relationship between a span and a cubit?
In many historical systems, a span was considered half (1/2) of a cubit. Since cubits themselves varied (e.g., common cubit vs. royal cubit), the exact length of the span derived this way also varied.
What is the relationship between a span and a palm or digit?
Common relationships, though varying by system, were:
- 1 span ≈ 3 palms (where a palm is the width of the hand).
- 1 span ≈ 12 digits (where a digit is the width of a finger).
Is the span an SI unit?
No, the span is not an SI unit. It is an ancient, non-standardized, anthropomorphic unit. The SI base unit for length is the meter (m).
Is the span still used today?
The span is not used for any official, scientific, or commercial measurements. Its use is limited to informal estimations, historical context, and figurative language. People might still use their own hand span for a quick size check.
Where does the name 'span' come from?
The word "span" comes from Old English spann, related to the verb spannan, meaning "to stretch, extend, or connect". This directly reflects the action of stretching the hand to measure the unit.
About Bolt (bolt)
How long is a bolt of cloth?
There is no single standard length. It depends heavily on the fabric type and manufacturer. Common lengths include:
- 40 yards (~36.58 m)
- 100 yards (~91.44 m)
- Other lengths like 30, 50, 60, or 120 yards are also possible. Always check the specific product information for the actual length of a particular bolt.
How many yards are in a bolt?
Commonly 40 yards or 100 yards, but this is highly variable.
How many meters are in a bolt?
Based on common yard lengths:
- A 40-yard bolt is approximately 36.58 meters.
- A 100-yard bolt is approximately 91.44 meters.
Is the bolt a standardized unit?
No, it is not a standardized unit of length like the yard or meter. It's a commercial trade unit whose length varies.
Is the bolt still used today?
Yes, the term "bolt" is still widely used in the wholesale textile industry and manufacturing contexts to refer to a full roll of fabric, although the precise length is usually specified in yards or meters.
Is this related to the fastener "bolt"?
No, the bolt unit for cloth is completely unrelated to the metal fastener known as a bolt. They share the same name but have entirely different meanings and origins.
Conversion Table: Span to Bolt
| Span (span) | Bolt (bolt) |
|---|---|
| 0.5 | 0.004 |
| 1 | 0.008 |
| 1.5 | 0.011 |
| 2 | 0.015 |
| 5 | 0.038 |
| 10 | 0.075 |
| 25 | 0.188 |
| 50 | 0.375 |
| 100 | 0.75 |
| 250 | 1.875 |
| 500 | 3.75 |
| 1,000 | 7.5 |
People Also Ask
How do I convert Span to Bolt?
To convert Span to Bolt, enter the value in Span in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our length converter page to convert between other units in this category.
Learn more →What is the conversion factor from Span to Bolt?
The conversion factor depends on the specific relationship between Span and Bolt. You can find the exact conversion formula and factor on this page. Our calculator handles all calculations automatically. See the conversion table above for common values.
Can I convert Bolt back to Span?
Yes! You can easily convert Bolt back to Span by using the swap button (⇌) in the calculator above, or by visiting our Bolt to Span converter page. You can also explore other length conversions on our category page.
Learn more →What are common uses for Span and Bolt?
Span and Bolt are both standard units used in length measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our length converter for more conversion options.
For more length conversion questions, visit our FAQ page or explore our conversion guides.
Helpful Conversion Guides
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📚 How to Convert Units
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⚖️ Metric vs Imperial
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Verified Against Authority Standards
All conversion formulas have been verified against international standards and authoritative sources to ensure maximum accuracy and reliability.
National Institute of Standards and Technology — Official US standards for length measurements
Bureau International des Poids et Mesures — International System of Units official documentation
Last verified: December 3, 2025