Measure your safe
Outside size with the door shut, including the plinth but not the castors.
How the calculator works
Two catalogues list sizes and weights side by side: George Hayter Chubb’s guide of 1875 for British safes and the 1899 catalogue of the Cary Safe Company of Buffalo, New York, for American ones.1,2 Across their ten examples, from a 43 cm safe of 152 kg to a 2 m office safe of almost 2.5 tonnes, the weight works out at about 1,050 to 1,750 kg per cubic metre of outside size, with small safes at the heavy end.
The calculator multiplies the volume of your safe by those two figures and shows the catalogue safe closest in size. This is our own working from the makers’ numbers, not a maker’s rule. The full tables and the reasoning are in our guide to how much an old safe weighs.
When the estimate can be wrong
- Burglar-resisting and bankers’ safes have thicker steel and can weigh well above the range.
- Concrete-filled safes of the 1930s onwards, such as Chatwood’s Duplex, are heavier for their size than Victorian safes filled with alum and sawdust.3
- A stamped weight beats any estimate. Chubb urged buyers to have the weight stamped on the safe, so check the back and base before you rely on a calculation.1
What the floor figure means
House floors are designed for loads spread across a room. In the United States the model code uses 30 to 40 lb per square foot for dwellings, about 150 to 195 kg per square metre, and England’s Approved Document A works from 2.0 kN per square metre, about 200 kg.4,5 A safe concentrates its whole weight on a small footprint, often on four castors. Design loads include safety margins and joists spread the load, so a high figure does not mean the floor will fail, but a heavy safe on a suspended timber floor is worth a structural engineer’s look.
Never lift a safe by hand: the UK Health and Safety Executive’s lifting guideline for one person is at most 25 kg.6 Our guide on what to do with an old safe covers moving, selling and finding a safe remover.
Not sure who made your safe or how old it is? Send us photos of its plate and serial number and we will help you identify it, free.
Frequently asked questions
How much does a small antique safe weigh?
Makers’ figures put a safe about 45 to 65 cm tall at roughly 150 to 200 kg. Chubb’s smallest in 1875, 43 × 56 × 41 cm, weighed 3 hundredweight, 152 kg.
How do I measure my safe?
Measure the outside height, width and depth with the door shut, including any plinth but not the castors. Handles and hinges that stick out make little difference to the weight.
Will my floor hold my safe?
On a ground-floor concrete slab, almost certainly. On a suspended timber floor, especially upstairs or in the middle of a span, ask a structural engineer, because a safe concentrates several times the design load of a house floor on a small area.
Is the result accurate?
It is an estimate from catalogue figures for ordinary fire-resisting safes. Treat the high number as the one to plan for, and check for a weight stamped on the safe.
Sources
- George Hayter Chubb, Protection from Fire and Thieves (London, 1875), ch. III (safes of Milner and Tann), ch. IV (fire-resisting materials) and ch. V (“Weights of good safes”), via Project Gutenberg. ↩︎
- Cary Safe Company, Buffalo, NY, trade catalogue (1899), “Diagrams and sizes”, pp. 4–8 (Nos. 2–10) and pp. 22–23 (Nos. 27–28), via Internet Archive. ↩︎
- safeman.org.uk, “Modern times”. ↩︎
- International Code Council, IBC Interpretation No. 37-07 (2007), reproducing Table 1607.1 of the 2006 International Building Code, item 28 (one- and two-family dwellings). ↩︎
- HM Government, Approved Document A: Structure (2004 edition incorporating 2010 and 2013 amendments), section 2C, paragraph 2C15 and Table 4 “Imposed loads”. ↩︎
- Health and Safety Executive, Manual handling at work: a brief guide, INDG143 (rev. 4, 2020), figure 1, “Lifting and lowering risk filter”. ↩︎