About
Built by people who had this problem
Contha is made by OWSH Unlimited LLC, a New York company. It is a small operation rather than a large one, and the product is built the way a small operation can afford to build: narrow, careful, and honest about where it stops.
Why it exists
Two sets of books that were never actually separate
Personal finance apps assume your balance is your money. That is true for somebody whose pay arrives already taxed, and false for everyone else. If any part of your income is not withheld, every one of those apps overstates what you have by exactly the tax you have not paid yet.
Business tools have the opposite problem. They model a company and treat your own life as out of scope, so the two halves end up in two places that disagree, and reconciling them becomes a March project.
Contha is one ledger with a side on every row. The personal half is a complete personal finance app and stands on its own. The business half sits on the same rows rather than on an import of them, which is why the tax figure can move as the year fills instead of being reconstructed at the end of it.
How it is built
Six commitments, each one structural
These are not values on a wall. Each is something the code does or refuses to do, and each is checkable from outside.
Nothing is paid to us for a recommendation
The card recommendations rank on your own spending against real reward structures. There is no affiliate link, no tracking parameter and no apply button anywhere on that surface, so the ranking cannot be bought and we cannot profit from which one wins. If that ever changes it will be written here and on the disclosures page before it ships.
The price you sign up at stays yours
Your subscription record carries its own price and the date it was locked, and every figure the app shows you comes from that record rather than from the current price list. The list can change. What you pay does not, until you change plan yourself. This is structural rather than a promise on a page.
A figure says when it is stale
Bank connections break, and the usual handling across this whole category is to keep showing the last number as though it were current. Contha names the account that is behind and by how many days, in the same sentence as the number it affects, and emails you once when a connection dies.
Your money stays where it is
Bank connections are read-only. Contha is not a bank, holds no money, and has no ability to move, freeze or spend anything. It reads balances and transactions and that is the whole of its access.
We do not sell your data
Not to advertisers, not to data brokers, and not into training anything. The token that reads your bank is encrypted with its own key, and access is enforced in the database on every table rather than in the interface.
No invented proof
This site carries no testimonials, no user counts and no star ratings, because there are none we could show you and stand behind. When there are real ones they will be real. The disclosures page says the same thing in the same words.
Where it stops
The things it does not do, said plainly
Contha does not file returns, send invoices, run payroll, or put a bookkeeper on your account. It computes and organises what a return is prepared from and hands it over whole, to you or to whatever accountant you already have.
Federal figures use the full 2026 brackets, the self-employment tax base and wage limit, the qualified business income deduction and the standard deduction. State income tax is modelled for 29 of the 51 filing jurisdictions. Itemized deductions, tax credits, capital gains and the §199A wage limitation are not modelled, and the estimate says so where it is shown. The states that are not modelled are named on the homepage rather than left for you to find out. Nothing here is tax advice; it is arithmetic with the rules it used shown beside it.
It will not tell an S-corp owner what salary to pay themselves. Reasonable compensation has no formula, and a number produced by software would be advice from something that is not qualified to give it.
Talk to us
hello@contha.com reaches a person. Questions about whether it fits your situation are welcome, including the ones where the answer is that it does not.