What is the 4:1 ladder angle rule?

The 4:1 rule means for every 4 metres of height, the base of the ladder should be 1 metre from the wall. This gives an angle of approximately 75° from the ground, which provides the best balance between stability and comfort. Too steep (over 80°) risks the ladder falling backwards; too shallow (under 70°) risks the feet sliding out.

How far should a ladder extend above the landing point?

A ladder should extend at least 1 metre (approximately 5 rungs) above the landing point or roof edge to provide a secure handhold for stepping on and off. Under the Work at Height Regulations, this is a requirement unless an alternative handhold is provided. Never step off a ladder at the top rung — always maintain three points of contact.

What is the maximum height for different ladder types?

Maximum heights per HSE guidance: single section ladder — 9m. Extension ladder — 15m (but consider alternatives above 9m). Stepladder — do not work above 4m. These are maximum limits; ladders should only be used for short-duration work (up to 30 minutes) at heights where the risk of injury from a fall is low. Consider scaffold or MEWP for longer tasks.

When should I NOT use a ladder?

Per HSE and the Work at Height Regulations, do not use a ladder if: the work will take more than 30 minutes, you need both hands for the work, the weather is poor (high winds, rain, ice), the ground is uneven or soft, there is no way to secure the ladder, or you need to carry heavy/bulky items. Use a scaffold, tower, or MEWP instead.

How should I secure a ladder?

Ladders must be prevented from slipping. Options in order of preference: (1) tie the top to a secure point, (2) tie the base (stiles, not rungs), (3) use a ladder stabiliser device, (4) have someone foot the ladder at the base. On soft ground, use a board under the feet. Never place a ladder on boxes, drums, or other unstable surfaces.

TradeCalculator

Ladder Safety Calculator — 4:1 Ratio, Height & Footing Check

Check ladder setup safety: correct 4:1 angle (75 degrees), maximum height limits, 1m extension above landing point, and footing type assessment.

Height to Access Point

Height to the landing or work point

Ladder Type

Select the ladder type available

Footing Type

Ground condition at ladder base

1m Extension Above Landing

Required for stepping on/off at top

How We Calculate This

This calculator checks ladder setup safety based on the 4:1 angle rule, height limits, and landing extension requirements per HSE guidance and the Work at Height Regulations 2005.

Safety checks

4:1 ratio: Base distance = height ÷ 4 (gives 75° angle)
Extension: 1m minimum above landing point
Max height: 9m single, 15m extension, 4m stepladder
Ladder length: √(height² + base²) from Pythagoras

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.