What this calculator does
Ladder angle & base distance works out safe base distance and length for a leaning ladder, using the 4-to-1 rule. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaBase = reach height / ratio; ladder length = √(height² + base²); angle = atan(height / base)
The inputs explained
| Field | What to enter |
|---|---|
| Height to reach (m) | A number, measured in m. Starts at 4. |
| Out-to-height ratio | A number. Starts at 4. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with height to reach
Every other input is held at the calculator’s starting values while height to reach varies. Select any row to load that scenario into the calculator.