Hi Ben,
drop me a line if you want to chat about this, but some general points to consider....
As you know the main thing is that you cannot just translate an employees salary into a day rate. It is not like-for-like. Think about that lowly wage you got as a digger, and then the 'astronomical' charge out rate the employer charges for your services. A lot of that extra is actually to pay the overheads associated with employing you. Not all, but a lot. You need to set a day rate that will generate a turnover sufficient to pay yourself some kind of income (this is where most freelance diggers stop thinking) which has to be earned over the 233 day working year,
but you also need to cover:
your insurance, this is usually only available for periods of 6 months so a fairly chunky payout
sickness insurance for when you can't work,
money for holiday pay and bank holidays
conferences and CPD/training as noone else will pay you to learn
pension
tax and NI
tools and equipment, computers, office stuff, software, phone, internet, possibly office space and bills
transport and accomodation, business car insurance, fuel
professional acreditation and memberships
It all adds up
Oh, and of course you'll have a proper legally sound contract and terms and conditions, and all the requisite H&S paperwork...
But almost certainly you won't be working all 233 days a year, so you need to plan for those slack days by upping your rate. You need to cover time to sort taxes and invoicing, and time to find and negotiate new work. Nothing will be done for you, and if it
is then start thinking about whether you are really working as self-employed.
There are some units who simply divide the PIfA minima by 233 working days, slap on a few quid and call that a day rate at ?63 a day. Another rather famous TV company used to pay a slightly higher rate. David's rates are far better, but I would say by its very nature you should be charging a higher rate than a similarly graded
employed person. The IfA says if you don't get holiday pay, pension rights or sick pay then as a basic digger you should get a MINIMUM of ?17613.15 instead of ?15054. So that is ?75 a day just to match the MINIMA for a digger, with NO expenses at all included and if you work all 233 days in the year. And I'd say as a freelancer you should be working off the recomended starting salaries, not the minima (
http://www.archaeologists.net/practices/salary).
The IfA published a breakdown a few years ago (in The Archaeologist) where the day rate for a generic specialist was worked out. To provide a comparible income to MIfA minima (then about ?21K) required a day rate of
?200 a day.
It is a good life when it goes well, and stressful when it goes badly. I enjoyed it, but am glad to be back in a unit where the life is more stable and someone else gets the contracts in.
There is some guidance and hopefully some examples on its way soon from the IfA.
Hope this helps
Chiz