Significant Figures (Sig Fig) Calculator

Significant Figures (Sig Fig) is evaluated from Number and Significant Figures. The calculation reports Rounded Value, Scientific Notation and Original Sig Figs.

Results

Thanks — we’ve logged this for review.

About the Significant Figures (Sig Fig) Calculator

Significant Figures (Sig Fig) is treated here as a quantitative relation between Number and Significant Figures and Rounded Value, Scientific Notation and Original Sig Figs.

The calculator uses a multi formula configuration. Each reported value is read as a direct evaluation of the stored rules with the declared field formats and units.

Formula basis:
_n = parseFloat(number)
_sf = parseInt(sig_figs)
_mag = _n !== 0 ? Math.floor(Math.log10(Math.abs(_n))): 0
_factor = Math.pow(10, _sf - 1 - _mag)
_raw = Math.round(Math.abs(_n) * _factor) / _factor
_roundedVal = _n < 0 ? -_raw: _raw
rounded = _roundedVal.toPrecision(_sf)
sci_not = (_n).toExponential(_sf - 1)
sig_count = 'Input has ~' + number.toString().replace('-','').replace('.','').replace(/^0+/,'').length + ' non-zero digits'

Interpret the outputs in the order shown by the result fields. Optional inputs affect only the outputs that depend on those variables.

Formula & How It Works

The calculation applies the following relations exactly as recorded in the metadata:

_n = parseFloat(number)
_sf = parseInt(sig_figs)
_mag = _n !== 0 ? Math.floor(Math.log10(Math.abs(_n))): 0
_factor = Math.pow(10, _sf - 1 - _mag)
_raw = Math.round(Math.abs(_n) * _factor) / _factor
_roundedVal = _n < 0 ? -_raw: _raw
rounded = _roundedVal.toPrecision(_sf)
sci_not = (_n).toExponential(_sf - 1)
sig_count = 'Input has ~' + number.toString().replace('-','').replace('.','').replace(/^0+/,'').length + ' non-zero digits'

Each output field is produced by substituting the supplied inputs into the relevant relation and then applying the declared rounding or text format.

Worked Examples

Example 1: Round 0.004523 to 3 significant figures

Inputs

number: 0.004523 sig_figs: 3
Rounded Value: 0.00452. Scientific Notation: 4.52e-3. Original Sig Figs: Input has ~4 non-zero digits

With Number = 0.004523 and Significant Figures = 3 as the stated inputs, the result is Rounded Value = 0.00452, Scientific Notation = 4.52e-3 and Original Sig Figs = Input has ~4 non-zero digits. Each value corresponds to the declared output fields.

Example 2: Round 12,345.6789 to 4 significant figures

Inputs

number: 12345.6789 sig_figs: 4
Rounded Value: 1.235e+4. Scientific Notation: 1.235e+4. Original Sig Figs: Input has ~9 non-zero digits

With Number = 12,345.6789 and Significant Figures = 4 as the stated inputs, the result is Rounded Value = 1.235e+4, Scientific Notation = 1.235e+4 and Original Sig Figs = Input has ~9 non-zero digits. Each value corresponds to the declared output fields.

Example 3: Round 0.100500 to 5 significant figures

Inputs

number: 0.1005 sig_figs: 5
Rounded Value: 0.1005. Scientific Notation: 1.0050e-1. Original Sig Figs: Input has ~4 non-zero digits

With Number = 0.1005 and Significant Figures = 5 as the stated inputs, the result is Rounded Value = 0.1005, Scientific Notation = 1.0050e-1 and Original Sig Figs = Input has ~4 non-zero digits. Each value corresponds to the declared output fields.

Example 4: Scientific constant: 6.674 × 10⁻¹¹ to 3 sig figs

Inputs

number: 6.674E-11 sig_figs: 3
Rounded Value: 6.67e-11. Scientific Notation: 6.67e-11. Original Sig Figs: Input has ~7 non-zero digits

With Number = 0 and Significant Figures = 3 as the stated inputs, the result is Rounded Value = 6.67e-11, Scientific Notation = 6.67e-11 and Original Sig Figs = Input has ~7 non-zero digits. Each value corresponds to the declared output fields.

Common Use Cases

  • Round lab measurements to correct sig figs
  • Express scientific notation with proper precision
  • Check chemistry or physics homework answers