Free tool for UK builders

Construction site welfare calculator

Enter the most people likely to be on site at any one time. You get the minimum number of toilets and washbasins from the tables in HSE’s guidance L24, and a list of the other welfare facilities CDM 2015 requires on every construction site.

Work out the welfare for your site

Enter the most people likely to be on site at any one time, then answer the questions that apply. Everything is worked out in your browser. Nothing you enter is sent to us.

Most people on site at any one time

Separate toilets for men and womenLeave this unticked if everyone shares toilets, each in its own room that locks from the inside.

Is there mains water and drainage on site?

YesNo, or not yet

The work heavily soils people’s face, hands and forearmsTemporary or mobile work, such as highway, utility or repair work

Enter the most people on site at any one time to see the numbers.

These are minimum numbers. More may be needed.

The calculator only reads HSE’s tables for the head count you enter. Plan for the real workforce, working hours, the distance to the facilities and how often they are cleaned and serviced.

Where the numbers come from

CDM 2015 Schedule 2 says toilets and washing facilities must be “suitable and sufficient”, but it does not give numbers. HSE’s construction welfare guidance says that, as an indication, you can use Tables 1 and 2 in the Approved Code of Practice to the Workplace (Health, Safety and Welfare) Regulations 1992. That is HSE’s publication L24. The calculator uses those tables.

Count the most people likely to be on site at any one time. That is what column 1 of each table means (L24, paragraph 197).

L24 Table 1: Number of facilities needed per number of people at work
Number of people at work	Number of cubicles	Number of washbasins
1 to 5	1	1
6 to 25	2	2
26 to 50	3	3
51 to 75	4	4
76 to 100	5	5

Table 1 applies where both men and women are working. If you provide separate toilets for a group of workers, such as men and women, L24 says to make a separate calculation for each group (paragraph 197). The calculator does that when you tick Separate toilets for men and women.

L24 Table 2: Number of facilities needed per number of men at work
Number of men at work	Number of cubicles	Number of urinals
1 to 15	1	1
16 to 30	2	1
31 to 45	2	2
46 to 60	3	2
61 to 75	3	3
76 to 90	4	3
91 to 100	4	4

Table 2 may be followed instead of column 2 of Table 1 if toilets are only used by men. A urinal may be an individual urinal or a section of urinal space at least 600 mm long (L24, paragraph 199). Table 2 has no washbasin column, so the washbasins for men still come from Table 1.

Above 100 people, add one toilet and one washbasin for every 25 people, or part of 25. For toilets only used by men, one more cubicle for every 50 men, or part of 50, above 100 is enough, as long as at least the same number of extra urinals is provided (L24, paragraph 200).

For dirty work that heavily soils the face, hands and forearms, L24 increases the washbasins to one for every 10 people, or part of 10, up to 50 people, and one more for every 20 people, or part of 20, above that (paragraph 201). The calculator never shows fewer washbasins than Table 1.

If you use portable chemical toilets, HSE’s guidance says the British Standard BS 6465-1:2006 recommends one toilet to seven people working a 40-hour week. Where that differs from the Table 1 number, provide the higher number. HSE adds that you also need to take into account how often they are serviced or emptied. They are usually emptied weekly, and you may need that done more often, or more units, depending on use.

Is this the law?

The duty to provide welfare is law. Schedule 2 to the Construction (Design and Management) Regulations 2015 sets the minimum welfare facilities for construction sites: toilets, washing facilities, drinking water, changing rooms and lockers, and rest facilities. HSE says everyone who works on a construction site must have access to toilets and facilities for washing, changing, eating and rest.

The numbers are guidance, not law, for a construction site. The Workplace (Health, Safety and Welfare) Regulations 1992 do not apply to construction work on construction sites. HSE says they “do give a guide to the numbers needed”. So the tables are a sensible starting point, but the legal test is still whether your facilities are suitable and sufficient for the people on your site.

Schedule 2 also says men and women need separate toilet rooms, unless each toilet is in its own room with a door that can be locked from the inside. HSE adds that men and women can share a toilet in a lockable room that is separate from any urinals, and can share sinks used to wash hands, face and arms. Provide sanitary waste disposal in facilities used by women.

Worked example

A builder expects up to 30 people on site at once: 4 women and 26 men, with separate toilets for men and women. There is no mains water or drainage yet.

Women (4): Table 1, 1 to 5 people, gives 1 toilet and 1 washbasin.
Men (26): Table 1, 26 to 50 people, gives 3 toilets and 3 washbasins. With urinals, Table 2, 16 to 30 men, gives 2 cubicles and 1 urinal instead of the 3 toilets.
In total: 4 toilets and 4 washbasins.
With portable chemical toilets at one to seven people working a 40-hour week: 1 for the women and 4 for the men, so 5.

Press Use the worked example in the calculator to load it.

What this calculator does not do

It gives minimum numbers from HSE’s tables. More may be needed, for example if everyone takes breaks at set times or finishes work together and needs to wash before leaving (L24, paragraph 197).
It does not decide whether your facilities are suitable. That depends on the work, the hazardous substances on site, the working hours, the distance to the facilities and how they are cleaned and serviced.
It does not cover first aid, which is a separate duty. See first aid facilities in our welfare guide.
It covers sites in Great Britain under CDM 2015.