Guide
How to split SaaS costs between co-founders
Domain, hosting, Notion, Slack, an AI plan. Small bills add up and quietly become the first fight. Here is a method that takes ten minutes a month.
Not legal, tax or financial advice. Rules differ by country. Use this to organise your thinking and check anything important with a professional.
The method in five steps
- Pick the ratio once. Equal is simplest. If one of you works full time and the other does not, use your share split. Write it down.
- Decide what counts. Anything the project needs to run: domain, hosting, database, email, design and AI tools, ads. Personal tools stay out.
- Log every bill the day it is paid, with who paid and the amount. A shared ledger beats memory.
- Set a limit. A single cost over an amount you agree, for example 100, needs a yes from both of you first.
- Settle monthly. Add up what each person paid, compare it to their share, and send one payment.
A worked example
Matt pays 12 for the domain and 20 for hosting. Partner pays 20 for an AI plan. The total is 52. With a 50/50 split each should pay 26. Matt paid 32, so Partner owes Matt 6. Try your own numbers in the cost split calculator.
Common traps
- Everything on one person's card. It works until that person leaves, and then the project's subscriptions leave with them. Note who pays for each tool.
- Yearly renewals. A domain or annual plan can hit months after you forgot. Log renewal dates.
- Different currencies. Pick one currency for the ledger and convert on the day you pay.
- No record of who owns the account. Cost splitting is half the job. Track who owns and can recover each account as well.
Do it with AI
Turn your bills into a ledger
Paste card lines or invoice emails and get a clean list you can drop into the calculator.
I run a side project with a co-founder. Below are card lines and invoice emails. Keep only costs that belong to the project and output one line per cost: "Item amount Payer", for example "Domain 12 Matt". Use one currency and ask me if conversion is needed. Then give the total and who is owed what at a [50/50] split. My name is [YOUR NAME]. Co-founder: [NAME]. Data: [PASTE HERE]
Frequently asked questions
What is the fairest way to split costs between co-founders?
Use the same ratio as your ownership shares, log every bill, and settle on a fixed day each month.
Should co-founders split costs 50/50?
If you own equal shares and both work on it, yes. If shares or effort differ, split costs by shares and write it down.
How do we split costs when one person pays for everything?
Log each bill with who paid. At month end the person who paid more is owed the difference by the other.
Is there a free tool for this?
Yes. Use the free cost split calculator or the project ledger sheet, or log costs in the WhoOwnsWhat.xyz app.
Related
Log a cost once and see who owes whom, always up to date.