MasterTool

Significant Figures Calculator

Calculate significant figures instantly in your browser.

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What this tool does

Calculate significant figures instantly in your browser. Results are shown as strings where needed so meaningful trailing zeros (like 3.20) are not lost.

How to use the Significant Figures Calculator

  1. Enter or select number (for count mode).
  2. Enter or select mode.
  3. Enter or select value a.
  4. Enter or select value b.
  5. Read the calculated result; change any measurement to compare alternatives.

Formula

Counting: nonzero digits always count, zeros between them count, leading zeros never count, and trailing zeros count only when a decimal point is present. Arithmetic: multiply/divide answers keep the fewest sig figs of the inputs; add/subtract answers keep the fewest decimal places.
value
Number (for count mode)
mode
Mode
a
Value a
b
Value b

Results are shown as strings where needed so meaningful trailing zeros (like 3.20) are not lost.

Worked example

For significant figures calculator, the following measurements illustrate the exact method: Number (for count mode): 1204.50; Mode: count; Value a: 12.34; Value b: 3.2.

Inputs

  • Number (for count mode)1204.50
  • ModeCount significant figures
  • Value a12.34
  • Value b3.2

Result

  • Significant figures6
  • Value1204.50

Results explained

Significant figures
Significant figures from the formula above. Results are shown as strings where needed so meaningful trailing zeros (like 3.20) are not lost.
Value
Value from the formula above. Results are shown as strings where needed so meaningful trailing zeros (like 3.20) are not lost.

Frequently asked questions

Counting: nonzero digits always count, zeros between them count, leading zeros never count, and trailing zeros count only when a decimal point is present. Arithmetic: multiply/divide answers keep the fewest sig figs of the inputs; add/subtract answers keep the fewest decimal places.

Results are shown as strings where needed so meaningful trailing zeros (like 3.20) are not lost.

Where mathematically meaningful, yes. Fields specify permitted ranges and undefined operations display an error.

Exact integer calculations use safe integers; decimal calculations use browser floating point, so small rounding differences can occur.

All values remain in your browser and are never uploaded.