Significant Figures Calculator
Count significant figures or round to specified precision
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📚 Examples, Rules & Help
⚡Quick Examples - Try These Calculations
🔍How Significant Figures Work
Understanding Significant Figures
Significant figures are the meaningful digits in a number that indicate precision.
Rules:
- All non-zero digits are significant
- Zeros between non-zero digits are significant
- Leading zeros are NOT significant
- Trailing zeros in decimals ARE significant
Rounding Process
Step 1: Identify all significant figures
Step 2: Keep the desired number of sig figs
Step 3: Look at the next digit
Step 4: If ≥ 5, round up; if < 5, round down
Step 5: Add zeros as placeholders if needed
🌍Real-World Applications
❓Frequently Asked Questions
What are significant figures and why do they matter?
Significant figures indicate the precision and reliability of a measurement or calculation.
They tell you how many digits in a number are meaningful and can be trusted.
Using the correct number of significant figures prevents false precision and maintains scientific accuracy.
How do I count significant figures?
Rules for counting significant figures:
• All non-zero digits are significant (123 has 3 sig figs)
• Zeros between non-zero digits are significant (105 has 3 sig figs)
• Leading zeros are NOT significant (0.012 has 2 sig figs)
• Trailing zeros in decimals ARE significant (1.20 has 3 sig figs)
• Trailing zeros in whole numbers may or may not be significant (depends on context)
When should I round to significant figures?
Round to significant figures when:
• Reporting scientific measurements
• Performing calculations with measured data
• Following laboratory or industry standards
• Avoiding false precision in results
The number of significant figures should reflect the precision of your least precise measurement.
What's the difference between precision and accuracy?
Precision refers to how many significant figures you use - how detailed your measurement is.
Accuracy refers to how close your measurement is to the true value.
You can have high precision (many sig figs) but low accuracy (wrong value), or vice versa.
How do significant figures work in calculations?
Addition/Subtraction: Round to the least number of decimal places
Multiplication/Division: Round to the least number of significant figures
🎯Common Use Cases
🔬 Laboratory Work
- • Measuring chemical concentrations
- • Recording experimental data
- • Calculating measurement uncertainty
- • Reporting research findings
🏭 Engineering & Manufacturing
- • Machining tolerances
- • Material specifications
- • Quality control measurements
- • Technical drawings and blueprints
🧪 Academic & Education
- • Chemistry lab calculations
- • Physics problem solving
- • Math and science homework
- • Understanding measurement concepts
📊 Data & Research
- • Statistical analysis
- • Research data presentation
- • Measurement validation
- • Scientific publication standards