Length Converter
Convert distance and measurement values between metric, imperial, nautical, print, and small-scale engineering units. The converter routes every value through meters so the table stays consistent across all supported units.
Base unit
meter
Supported units
17
Includes
metric + imperial
Live converter
Length conversion inputs
Enter a value, choose source and target units, then review the full conversion table for nearby metric and imperial units.
Converted result
30.48 cm
Input
12 in
Output unit
cm
Base method
meters
Length in every supported unit
| Unit | Converted value | Unit name |
|---|---|---|
| nm | 304,800,000 | Nanometers |
| um | 304,800 | Micrometers |
| mm | 304.8 | Millimeters |
| cm | 30.48 | Centimeters |
| dm | 3.048 | Decimeters |
| m | 0.3048 | Meters |
| dam | 0.03048 | Decameters |
| hm | 0.003048 | Hectometers |
| km | 0.0003048 | Kilometers |
| mil | 12,000 | Mils |
| in | 12 | Inches |
| ft | 1 | Feet |
| yd | 0.333333333333 | Yards |
| mi | 0.000189393939394 | Miles |
| nmi | 0.000164578833693 | Nautical miles |
| pt | 864 | Points |
| pc | 72 | Picas |
Base unit
meter
Supported units
17
Includes
metric + imperial
Convert measurements for documents, drawings, and field notes
Map and route distances
Move between meters, kilometers, feet, yards, miles, and nautical miles when comparing maps, travel notes, and route estimates.
Drawing dimensions
Translate millimeters, inches, points, and picas for print layouts, packaging, labels, and design specs.
Lab and shop measurements
Convert small measurements such as nanometers, micrometers, millimeters, mils, and centimeters without losing the base-unit logic.
Length conversion formula
The page converts the input into meters first, then divides by the target unit factor. That keeps metric prefixes and inch-pound units on one consistent method.
Working formulas
Base conversion
meters = value x meters per source unit
The input is first normalized to meters.
Target value
target value = meters / meters per target unit
The normalized meter value is divided by the target unit factor.
Exact inch relationship
1 inch = 0.0254 meter
This exact relationship anchors inch, foot, and yard conversions.
Symbols
- meters per source unit - source factor
- The official or exact meter factor for the selected source unit.
- meters per target unit - target factor
- The meter factor used to scale the base value into the target unit.
Why the length converter is practical
Full comparison table
- Every result includes all supported units, so users can compare nearby units without repeating the same conversion.
- Very small or very large values switch to scientific notation to avoid unreadable strings of zeros.
- The table includes print units, nautical miles, and engineering units, not only the common classroom set.
Source-backed factors
- Metric prefix values follow the SI meter scale, while inch-pound values use the international foot and exact inch relationship.
- The formula section explains the base-unit route so users can audit the arithmetic instead of trusting a black-box result.
- The same conversion library also supports geometry calculators, keeping length, area, and triangle outputs consistent.
Useful for measurement-heavy work
Design and drafting
Check drawing dimensions, print measurements, packaging dielines, and layout specs that mix inches, points, picas, and millimeters.
Science classes
Convert across metric prefixes for lab problems involving very small lengths or large distance scales.
Travel and navigation
Compare miles, kilometers, meters, feet, and nautical miles for routes, maps, aviation, and marine notes.
How it works in three quick steps.
Enter the measurement
Type the length value exactly as it appears in the source document, drawing, map scale, classroom problem, or product specification.
Choose source and target units
Select the unit you have and the unit you need. The result updates immediately and the table shows the same value in every supported unit.
Check the meter factor
Use the formula section and conversion table to verify whether the result came from metric prefixes, international inch-pound units, or nautical miles.
Save length conversions cleanly
Copy result
Copy the selected source-to-target conversion with unit labels for worksheets, tickets, documents, and emails.
Print reference table
Print the full conversion table when a project needs repeated length lookups during field or classroom work.
Use formula notes
Keep the meter-based formula visible so another person can verify which conversion factors were used.
Frequently Asked Questions
How does the length converter calculate results?
Which length units are included?
Are feet and inches exact conversions?
Why do some answers appear in scientific notation?
Can I use this for print measurements?
Related unit converters
About this length converter
Length conversion seems simple until a document mixes small metric values, print units, construction dimensions, and travel distances. A drawing may use millimeters, a product sheet may use inches, a route note may use miles, and a marine reference may use nautical miles. This converter keeps those cases together by routing every calculation through meters, the SI base unit for length.
The full conversion table is intentionally visible because one target unit is rarely enough in practical work. A user checking 12 inches may also want centimeters, millimeters, feet, yards, and points without retyping the input. The table gives that comparison immediately while the selected result remains prominent above it.
The formula notes use official measurement relationships such as the exact inch-to-meter definition and metric prefix scaling. This makes the page useful for quick answers and for audit-friendly work where another person needs to understand how the number was produced.
Who maintains this page
Ownership and review
Written and maintained by the Toolarithm editorial team. No review date is shown without a maintained editorial record. No independent professional review is claimed.
Methodology
Conversion factors are normalized to canonical units and checked in both directions. Exact definitions and offset formulas are preferred over rounded lookup values.
Read the editorial methodologyDates and sources
Review dates change only after a substantive method or content check.
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