Numbers and Measurements — Formatting Standards for Technical Documentation

In this tutorial, you will learn about Numbers and Measurements. We cover key concepts, practical examples, and best practices to help you master this topic.

Numbers and measurements appear frequently in technical documentation. Consistent formatting of numerals, units, decimals, percentages, and ranges improves readability and prevents misinterpretation.

In this lesson, you will learn standards for formatting numbers and measurements in technical documentation.

What You'll Learn

You will understand when to use numerals versus words, format units and measurements consistently, and handle ranges and percentages correctly.

Why It Matters

Inconsistent number formatting confuses readers. Writing 100 MB in one place and one hundred megabytes in another makes documentation seem unprofessional.

Real-World Use

DodaTech standardized on numerals for all numbers 10 and above, spelled-out for numbers under 10. This rule eliminated inconsistency across thousands of pages.

flowchart LR
  A[Numbers] --> B{Under 10?}
  B -->|Yes| C[Spell out]
  B -->|No| D[Use numerals]
  B -->|Technical| E[Always numerals]
  C --> F[three algorithms]
  D --> G[100 MB]
  E --> H[8 GB RAM]
  A:::current
  classDef current fill:#f90,color:#fff,stroke:#333,stroke-width:2px

Numerals vs Words

Spell out numbers under 10. Three algorithms, seven files, nine parameters.

Use numerals for numbers 10 and above. 15 files, 100 MB, 256 parameters.

Always use numerals for technical measurements. 8 GB RAM, 2.5 GHz, 64-bit.

Never start a sentence with a numeral. Write Ten files were processed not 10 files were processed.

# Numbers under 10: spell out
- Three compression algorithms
- The first step
- Seven supported formats

# Numbers 10 and above: numerals
- 15 files compressed
- 100 MB memory limit
- 256 GB maximum storage

# Technical measurements: always numerals
- 8 GB RAM
- 2.5 GHz processor
- 64-bit architecture

Units and Measurements

Include a space between the number and unit. 100 MB not 100MB. The exception is degrees and percentages: 100%, 45 degrees.

Use standard abbreviations for units. MB, GB, KB, ms, s, GHz. Define non-standard units on first use.

Be consistent with decimal separators. Use a period for decimal. For large numbers, use commas: 1,000,000 or spaces: 1 000 000.

# Unit formatting
- 100 MB (space between number and unit)
- 45 degrees (no space before degree symbol)
- 100% (no space before percent)

# Large numbers
- 1,000,000 bytes (commas)
- 1 000 000 bytes (spaces - SI standard)
- 1 million bytes (words for round numbers)

Common Mistakes

1. Mixing Numerals and Words Inconsistently

Three files in one sentence and 3 files in another. Pick a rule and follow it.

2. No Space Before Unit

100MB instead of 100 MB. Most style guides require a space.

3. Starting Sentences with Numerals

10 files were processed should be Ten files were processed.

4. Inconsistent Decimal Format

Using commas for decimals in one place and periods in another. Pick one and stay consistent.

5. Wrong Unit Case

Using Mb instead of MB for megabytes. Case matters in units.

6. Mixing Units in Comparisons

100 MB vs 1 GB. Use the same unit or include both units for clarity.

7. Unnecessary Precision

3.1415926535 when 3.14 is sufficient. Round to reasonable precision.

Practice Questions

1. When should you spell out numbers?

Numbers under 10 should be spelled out. Three algorithms, seven files.

2. When should you use numerals?

Numbers 10 and above. Also always use numerals for technical measurements.

3. How should units be formatted?

Number, space, unit. 100 MB. No space for percent and degree symbols.

4. What is the rule for starting a sentence with a number?

Do not start a sentence with a numeral. Rewrite the sentence or spell out the number.

5. Challenge: Find 10 number formatting errors in a documentation page. Correct each one and categorize the type of error.

FAQ

Mini Project

Create a numbers and measurements style guide for a documentation project. Include rules for numerals vs words, units, percentages, ranges, time, version numbers, and currency. Provide examples.

What's Next

Next: Code Style in Text