Guesstimate

Ever wonder "what's the answer if this number could be anywhere from 2 to 4?" Guesstimate is a calculator built for uncertainty.

Use the ~ operator to define ranges in your formulas. For example, (2~4) * (1~3) means "a number between 2 and 4, multiplied by a number between 1 and 3." Guesstimate runs hundreds of thousands of Monte Carlo simulations to show you the full distribution of possible results.

FEATURES

- Uncertainty ranges: Use ~ to express "somewhere between" in any formula
- Monte Carlo simulation: Up to 10 million iterations for accurate results
- Interactive histogram: Tap bars to see exact percentages and sample counts
- Box plot visualization: See min, Q1, median, Q3, and max at a glance
- Full statistics: Mean, median, standard deviation, confidence intervals, and percentiles (P1 through P99)
- Calculation history: Review and reload past formulas
- Configurable settings: Adjust iteration count, histogram bins, confidence level, and distribution type (uniform or normal)
- Built-in calculator keypad: No keyboard needed — dedicated buttons for digits, operators, parentheses, and the ~ range operator
- Works on iPhone and iPad

EXAMPLES

- How much will dinner cost? (12~18) + (8~14) + (3~7)
- Estimating project hours? (2~4) * (5~8)
- Unit conversion with uncertainty? (2.79~3.09) * ((1300~1400) / (27~33))

No account required. No data collected. Just math.