What size bouncy castle do I need?

For up to 6 children, a small 3m x 3m castle works. For 7-10 children, go medium (4.5m x 4.5m). For 11-15 children, you need a large (6m x 6m). Combo castles with slides are 6m x 4.5m and hold up to 12. Always follow the hire company's stated maximum capacity.

How much space do I need around the bouncy castle?

You need at least 1.5 metres of clear space on ALL sides of the bouncy castle. This is for safety - children can bounce off or fall near the entrance. So a 4.5m castle needs a garden area of at least 7.5m x 7.5m. The ground must be flat and free of sharp objects.

How much does bouncy castle hire cost?

Small castles hire from £50-£80 for a half day. Medium castles cost £70-£120. Large castles and combos with slides range from £100-£200. Weekend rates are higher than weekday. Most hire includes delivery, setup, and collection.

What about safety rules?

Maximum capacity must be followed. Children must be supervised at all times by an adult. Remove shoes, glasses, and sharp objects before bouncing. Do not use in wind over 24mph. Separate age groups - never mix under-5s with older children. The hire company should provide a safety briefing.

Bouncy Castle Calculator — Size & Space

Work out the right bouncy castle size and check it fits your space.

Number of Children

Number of children

Castle Size

Castle size

Garden Length

Garden length

Garden Width

Garden width

Hire Cost

Amount in pounds sterling

Hire Duration

Total duration of the event or activity

How We Calculate This

This calculator checks whether your chosen bouncy castle fits your garden and estimates costs.

How it works

Required space = castle dimensions + 1.5m clearance each side
Fits in garden = garden >= required space
Cost per child = hire cost / number of children
Cost per hour = hire cost / hire duration

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Adjust quantities based on your guests and event type.