How to split revenues in software project, how to come up with easy quick agreement for small project

Well if your not a company (and I suggest you create one) then you basically say

• Revenue - Running expenses = Profit
• Running expenses can be servers, wages, coffee, travel, marketing costs for Ads etc.

You then take the profit every 3/6 or 12 months and say we will invest X% back into the company to grow and we will spilt the remainder between us.

How you split it comes down to what you can all agree on. 1/4 each sounds about the fairest unless someone is doing far more or far less than the others and then it gets trickier.

You are then pretty much counting hours worked, giving each hour a sweat effort multiplier and then granting a "value" provided through specific skills, basically Marketing unless they are watching the website full time and tweaking things won't be working as hard as the developers ... you will need to balance this.

I have given a few answers on ways to do this previously:

• Considering a Partner. This is probably the most detailed list of things to consider including how to split shares.
• Why do startups need so much money. This covers the range of expenses you will need to consider.
• Partnerships and revenue sharing. This is pretty similar to your question, though my answer has changed a bit over time. Joseph also has a good answer for the question which is worth a read.
• Esablishing shared ownership. This looks at methods of covering the various inputs people can make.
• Revenue split for boardgame. Slightly different but it looks at the IP ownership issues around reusing ideas and how you can cover it off with the originator.
• Estimated costs of a startup. This is another look at how you work out the costs associated with running you project.

Hopefully this gives you a bit of a starting point.

Robin's answer was best for your question but I'd like to throw in a caution, which may be totally unneeded but just might be helpful: pay attention to how any discussion about money is going.

If one individual is problematic and really really wants to make sure everything is going to be fair someday, when there may or may not be any money, look out: you may find yourself having to justify your 5 cups of coffee to his 3 at a later date.

Okay, that said, if everyone is groovy and just no idea how to tackle a split I would vote for equal shares and expect equal effort. The company won't succeed without a backend, and equally won't succeed if no ones sells it. If the marketer has nothing to sell early on they can be building social networks to sell into later, building buzz, teaser pages, generating test data for the backend, something. If the backend has less to do later they can be optimizing, planning for expansion, making calls for the marketer, again, something. IMHO experience there's no shortage of tasks to do, just (sometimes) shortage of commitment.