Significant Figures Calculator

Count significant figures, perform calculations with proper sig fig rules, and round numbers.

Count Significant Figures

Enter a number to count its significant figures.

Example Numbers:
⭐ Leading Zeros (Not Significant)
0.00450 0.0123 0.500
⭐⭐ Trailing Zeros (Context Matters)
1200 1200. 1200.0 120
⭐⭐⭐ Trapped Zeros (Always Significant)
1002 50.03 1.0023
⭐⭐⭐⭐ Scientific Notation
1.23×10⁵ 4.500×10⁻³ 6.02×10²³
Arithmetic with Sig Figs

Perform calculations following significant figure rules.

Example Calculations:
⭐ Addition (Decimal Places)
12.34 + 5.6 100.5 + 23.456
⭐⭐ Subtraction (Decimal Places)
45.67 − 12.3 1000 − 5.5
⭐⭐⭐ Multiplication (Sig Figs)
12.34 × 5.6 0.0045 × 123
⭐⭐⭐⭐ Division (Sig Figs)
45.67 ÷ 12.3 100 ÷ 3.0
Round to Significant Figures

Round a number to a specific number of significant figures.

Example Problems:
⭐ Basic Rounding
123.456 → 3 sig figs 0.004567 → 2 sig figs
⭐⭐ Large Numbers
12345 → 3 sig figs 98765 → 2 sig figs
⭐⭐⭐ Decimal Numbers
45.678 → 4 sig figs 0.123456 → 3 sig figs
Scientific Notation

Convert numbers to/from scientific notation.

Example Conversions:
⭐ Small Numbers
0.00456 0.0000789
⭐⭐ Large Numbers
123000 Avogadro's number
⭐⭐⭐ Already in Scientific
1.23×10⁵ 4.5×10⁻³
Results


Enter a number and click Calculate

Significant Figures Rules
Counting Significant Figures
  1. All non-zero digits are significant
    Example: 123 has 3 sig figs
  2. Trapped zeros are significant
    Example: 1002 has 4 sig figs
  3. Leading zeros are NOT significant
    Example: 0.0045 has 2 sig figs
  4. Trailing zeros after decimal ARE significant
    Example: 1.200 has 4 sig figs
  5. Trailing zeros without decimal are ambiguous
    Example: 1200 has 2-4 sig figs (use scientific notation)
Calculation Rules

Addition & Subtraction:

Round to the fewest decimal places

12.34 + 5.6 = 17.9 (not 17.94)

Multiplication & Division:

Round to the fewest sig figs

12.34 × 5.6 = 69 (2 sig figs from 5.6)
Scientific Notation

Format: a × 10n

Where 1 ≤ |a| < 10

Example: 1200 = 1.2 × 10³ (2 sig figs)
Example: 0.00456 = 4.56 × 10⁻³ (3 sig figs)

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