Anyone contract through Hays

[JRCT]

I do compare gross rates - not net rates vs gross rates

Unfortunately, you are comparing gross with net.

Hays aren't going to say to you "tick box A and we'll pay you X, tick box B and we'll pay you X+13%. We don't mind how much it costs us"

[aphrodita]

Hays are currently paying employers NI for you. With the umbrella it's deducted from your rate. This would account roughly for the 13.5% uplift.

Thank you for this one - I will make sure to ask this question with one of guys from an umbrella company. I just know that for other person who came on board, Hays was offering X amount of money, but net income would be about 0.7X. So he wanted to pass on the offer and only then they told him about umbrella companies. Now his income 0.85X after all taxes + expenses are paid.

He declared breakfast + lunch + millage, which came out at £143/week. I live closer to work, so my expenses might be £110-£130, but still... comes to a reasonable amount of untaxed expenses per month...

[aphrodita]

Unfortunately, you are comparing gross with net.

Contract only states net rates, I didn't go deep into calculating net....

Another thing I understand - the further you live from work the more beneficial it is for you. If you're away for <10 hours, you're entitled to £5 meal/day + millage; if you're away from home for more than 10 hours, you're entitled to £10 meal/day + millage.

Another difference in net received comes from the fact that Hays take a particular % to handle your finances, while an umbrella company charges you £21-£28 pounds a week.

[kingcook]

[DannyF1966]

the further you live from work the more beneficial it is for you.

Not necessarily. Mileage rates reduce after you've done 10,000 business miles per year, and if you've piled the miles onto your car you'll have to replace it sooner, plus it'll cost more in maintenance due to extra wear and tear.

Also, with claiming back expenses for food, bear in mind that you still have to pay for the food in the first place, it's not a free £5 or £10 that magically appears in your wallet. I've just switched to bringing a packed lunch to work because spending £24 a week just to reduce my CT bill by £4.80 is more expensive than buying the ingredients for a packed lunch out of my own pocket in the first place. I'd rather keep the money in the business and use it to build up the warchest or increase the company's pension contributions.

[TykeMerc]

I've made my calculations and if I'm going to work through an umbrella company - my hourly rate goes up by 13.5%. I am losing 2% pension (0.8% I'm paying + 0.20% paid by government + 1% Hays contributes), however I'm still earning 11.5% more + my expenses are paid.

The only downside - I have to put aside money for the holiday pay myself instead of Hays doing it to me.

Are there any other perks one should be aware before deciding to go self-employed?

It's very clear from your posts that you're either grossly misunderstanding the information you have got or are missing large chunks of vital information, in either situation I'm very concerned that you can't make a sensible choice.

Firstly the 13% "Uplift" if you went via an umbrella.
In your current contract with Hays they are in effect acting in many ways like an Umbrella company. You are paid as an employee of Hays, they are charging you to their client as a temp at a daily rate and paying you that rate AFTER they have already deducted the 13% Employers NI they must pay for employing you.
If you changed employer to an Umbrella then instead of deducting that 13% up front Hays will pay that to your Umbrella who will then deduct it in exactly the same way that Hays do.
Net effect on your rate of this 13% is NIL, nothing, zero, nada, nowt

Your employment status via Hays or Umbrella
In either case you are NOT, nor will ever be self employed, you will be a fully employed person on Hays or Umbrella payroll, subject to the terms of your employment contract.

Expenses and other benefits
I've never worked as a temp, but from what you've described the position on expenses may be better if employed via an Umbrella (where you still will be employed, NOT self employed) so that may be a positive, not forgetting that expenses can only be claimed to a non permanent place of work, i.e. your usual place of work should be elsewhere like your home.
To the best of my knowledge (which could easily be wrong) Umbrellas don't pay pensions you would have to investigate what's the true state of that. They also don't pay holidays or sick leave, you may get those via Hays as their employee.

Costs
You mentioned Hays are charging a management fee (percentage based) and the Umbrella is charging a fixed fee. There are many Umbrella companies out there and their charging structures vary, I'd assume that even the percentage fee ones have a minimum charge.

You really need to get much better informed before you jump into changing your current situation.