Individuals
Check your own tax before you file it.
Upload what you have and see every option computed, what your documents establish, and what they leave open — before anyone else looks.
Try it free →The tax operating system
Tax you can defend.
CLAVIS reads the documents, applies the law in force for the year, computes every figure twice and keeps the record — and says plainly what it cannot establish.
For individuals checking their own tax, practices that sign for their clients, and platforms that verify at scale.
Live today for income tax in India. No sign-up; the trial computes and stores nothing.
Computation of total income
| Line | Old regime | New regime | Check |
|---|---|---|---|
| s.17(1)Salary | ₹13,20,000 | ₹13,20,000 | from the working |
| s.16(ia)Standard deduction | −₹50,000 | −₹75,000 | from the working |
| s.288ATotal income, rounded | ₹12,70,000 | ₹12,45,000 | from the working |
| RatesTax on total income | ₹1,93,500 | ₹66,750 | from the working |
| s.87ARebate, with marginal relief | ₹0 | −₹21,750 | from the working |
| Finance ActHealth and education cess | ₹7,740 | ₹1,800 | from the working |
| s.288BTax payable | ₹2,01,240 | ₹46,800 | recomputed by the second engine |
| s.56Income from other sources | not known | not known | |
Not known, and said so. “No AIS, TIS or Form 26AS was uploaded. An employer's Form 16 reports only what that employer paid, so nothing here can show that other income — a second employer, bank interest, dividends — is absent.”
Inside a marginal-relief band. The next ₹10,000 of salary costs ₹10,400 of tax — 104%.
Tax work is exact, seasonal and signed.
It arrives at once. In India, 69.92 lakh returns were filed on 31 July 2024 alone. The hours to check them do not arrive with them.
The authority already knows. Tax departments hold what employers, banks and brokers report. In India the AIS carries salary, interest, dividends and every TDS credit — a return that leaves one out is visibly short.
One name signs. Liability does not spread across the people who prepared a return. It stays with the name on the last page.
How it works
One system, from the documents to the signed result.
A tax operating system is not a calculator with a login. It is every step a figure passes through, each one checking the step before.
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01
Documents in
Certificates, statements and proofs are read for what they are, and each one reports what it could not read.
What it reads in India — 18 kinds of document
From the department
- Annual Information Statement (AIS) and TIS
- Form 26AS, and its successor Form 168
- Form 16A, and its successor Form 131
- Form 132 (the successor to Forms 16B to 16E)
From the employer
- Form 16, Parts A and B
- Form 12BA and the Part B salary annexure
- Salary slips
- Offer letters
Proofs behind a claim
- Rent receipts
- Home-loan interest certificates
- Section 80C investment proofs
- Health-insurance premium receipts
- Donation and medical receipts
- Form 10E (arrears relief)
Markets and banks
- Capital-gains statements
- Bank statements (interest credited)
- Broker tradebooks, matched first-in first-out
- Broker tax P&L statements
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02
The law, as data
Each jurisdiction's law compiles into its own ruleset, versioned by year and pinned to every result. A year is computed under the law that governs it — or refused by name.
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03
Computed twice
Every figure comes from the main engine and again from a second engine written separately. They must agree before CLAVIS puts its name to the result.
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04
Kept as a record
What was computed, under which rules, and what was filed — kept per client and year and never overwritten. A correction is a new record beside the old one.
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05
Reviewed by people
A review queue ranks the work by what needs judgement first. Each finding carries a reason, an action, and the provision behind it where there is one.
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06
Out as evidence
An evidence dossier per return that a person can print and hand over, and an export for the person who files.
Who it's for
For everyone who answers for a tax figure.
Practices and firms
Every client-year, in one place.
The working, the review queue, the filing state and the history of every client, with each figure traced — so the partner signs a return they can defend.
See the plans →Businesses and platforms
Verify the figures your software produces.
Payroll, lending and filing platforms send a figure and the facts behind it; the verification API says whether CLAVIS's two engines agree, and why.
Talk to us →The principle
It never claims more than the documents show.
Most software answers every line. CLAVIS answers the lines it can establish, marks the ones it cannot, and says what would settle them. A reviewer reads a return differently when the blanks are named.
2. Definitions.—In CLAVIS, unless the context otherwise requires,—
- (a) “known”
- means a figure read from a document line, or computed from such figures, with the provision that governs it;
- (b) “awaiting evidence”
- means an amount on the page whose allowance is not yet shown — the remedy is a document, not a number;
- (c) “not known”
- means an amount no document here establishes — named, together with the document that would;
- (d) “not asserted”
- means a figure CLAVIS will not put its name to — a relief it surfaces but does not apply, or a result its own two engines disagree on.
Before anyone signs
What it checks on every return.
Your filing software computes the return from what someone keyed in. CLAVIS computes it again from the documents and shows every line where the two stories differ.
Every figure traced
Each amount to the document line it came from and the provision that allows it — printable as the working you hand over.
Every option computed in full
Where the law offers a choice — India's two regimes, for one — both are computed completely, and the recommendation is the comparison.
Sources that disagree, shown
When an employer's certificate, the tax statement and the information report differ, the higher-authority source is used by a stated order — and the disagreement is shown, not averaged away.
Every credit matched to its income
Each tax credit is placed at a head of income, recorded as not income, or held with the question that would place it.
The bands a rate table hides
Where a threshold makes the next unit of income cost more than it earns, the rate is measured by re-running the engine, not read off a table.
The right law for the year
When the law itself changes — India's Acts of 1961 and 2025 — each year is computed under the one that governs it, never the other.
Proof, not adjectives
Shown, on India's income tax, where CLAVIS is live.
A cliff a rate table cannot show
Effective marginal rate on salary under India's new regime, AY 2026-27. Each dot is a real run of the engine: the tax at one income, and again with ₹10,000 more. From ₹12.75 lakh to ₹13.38 lakh of salary the next rupee costs more than a rupee — where a slab table says 15%. After it, 87.1%.
The 61 measurements behind this chart
| Gross salary | Total income | Tax | Rate on the next ₹10,000 | Band |
|---|---|---|---|---|
| ₹10,00,000 | ₹9,25,000 | ₹0 | 0% | |
| ₹10,12,500 | ₹9,37,500 | ₹0 | 0% | |
| ₹10,25,000 | ₹9,50,000 | ₹0 | 0% | |
| ₹10,37,500 | ₹9,62,500 | ₹0 | 0% | |
| ₹10,50,000 | ₹9,75,000 | ₹0 | 0% | |
| ₹10,62,500 | ₹9,87,500 | ₹0 | 0% | |
| ₹10,75,000 | ₹10,00,000 | ₹0 | 0% | |
| ₹10,87,500 | ₹10,12,500 | ₹0 | 0% | |
| ₹11,00,000 | ₹10,25,000 | ₹0 | 0% | |
| ₹11,12,500 | ₹10,37,500 | ₹0 | 0% | |
| ₹11,25,000 | ₹10,50,000 | ₹0 | 0% | |
| ₹11,37,500 | ₹10,62,500 | ₹0 | 0% | |
| ₹11,50,000 | ₹10,75,000 | ₹0 | 0% | |
| ₹11,62,500 | ₹10,87,500 | ₹0 | 0% | |
| ₹11,75,000 | ₹11,00,000 | ₹0 | 0% | |
| ₹11,87,500 | ₹11,12,500 | ₹0 | 0% | |
| ₹12,00,000 | ₹11,25,000 | ₹0 | 0% | |
| ₹12,12,500 | ₹11,37,500 | ₹0 | 0% | |
| ₹12,25,000 | ₹11,50,000 | ₹0 | 0% | |
| ₹12,37,500 | ₹11,62,500 | ₹0 | 0% | |
| ₹12,50,000 | ₹11,75,000 | ₹0 | 0% | |
| ₹12,62,500 | ₹11,87,500 | ₹0 | 0% | |
| ₹12,74,900 | ₹11,99,900 | ₹0 | 103% | over 100% |
| ₹12,75,000 | ₹12,00,000 | ₹0 | 104% | over 100% |
| ₹12,75,100 | ₹12,00,100 | ₹100 | 104% | over 100% |
| ₹12,87,500 | ₹12,12,500 | ₹13,000 | 104% | over 100% |
| ₹13,00,000 | ₹12,25,000 | ₹26,000 | 104% | over 100% |
| ₹13,12,500 | ₹12,37,500 | ₹39,000 | 104% | over 100% |
| ₹13,25,000 | ₹12,50,000 | ₹52,000 | 104% | over 100% |
| ₹13,37,500 | ₹12,62,500 | ₹65,000 | 87.1% | |
| ₹13,50,000 | ₹12,75,000 | ₹74,100 | 15.6% | |
| ₹13,62,500 | ₹12,87,500 | ₹76,050 | 15.6% | |
| ₹13,75,000 | ₹13,00,000 | ₹78,000 | 15.6% | |
| ₹13,87,500 | ₹13,12,500 | ₹79,950 | 15.6% | |
| ₹14,00,000 | ₹13,25,000 | ₹81,900 | 15.6% | |
| ₹14,12,500 | ₹13,37,500 | ₹83,850 | 15.6% | |
| ₹14,25,000 | ₹13,50,000 | ₹85,800 | 15.6% | |
| ₹14,37,500 | ₹13,62,500 | ₹87,750 | 15.6% | |
| ₹14,50,000 | ₹13,75,000 | ₹89,700 | 15.6% | |
| ₹14,62,500 | ₹13,87,500 | ₹91,650 | 15.6% | |
| ₹14,75,000 | ₹14,00,000 | ₹93,600 | 15.6% | |
| ₹14,87,500 | ₹14,12,500 | ₹95,550 | 15.6% | |
| ₹15,00,000 | ₹14,25,000 | ₹97,500 | 15.6% | |
| ₹15,12,500 | ₹14,37,500 | ₹99,450 | 15.6% | |
| ₹15,25,000 | ₹14,50,000 | ₹1,01,400 | 15.6% | |
| ₹15,37,500 | ₹14,62,500 | ₹1,03,350 | 15.6% | |
| ₹15,50,000 | ₹14,75,000 | ₹1,05,300 | 15.6% | |
| ₹15,62,500 | ₹14,87,500 | ₹1,07,250 | 15.6% | |
| ₹15,75,000 | ₹15,00,000 | ₹1,09,200 | 15.6% | |
| ₹15,87,500 | ₹15,12,500 | ₹1,11,150 | 15.6% | |
| ₹16,00,000 | ₹15,25,000 | ₹1,13,100 | 15.6% | |
| ₹16,12,500 | ₹15,37,500 | ₹1,15,050 | 15.6% | |
| ₹16,25,000 | ₹15,50,000 | ₹1,17,000 | 15.6% | |
| ₹16,37,500 | ₹15,62,500 | ₹1,18,950 | 15.6% | |
| ₹16,50,000 | ₹15,75,000 | ₹1,20,900 | 15.6% | |
| ₹16,62,500 | ₹15,87,500 | ₹1,22,850 | 15.6% | |
| ₹16,74,900 | ₹15,99,900 | ₹1,24,780 | 20.8% | |
| ₹16,75,000 | ₹16,00,000 | ₹1,24,800 | 20.8% | |
| ₹16,75,100 | ₹16,00,100 | ₹1,24,820 | 20.8% | |
| ₹16,87,500 | ₹16,12,500 | ₹1,27,400 | 20.8% | |
| ₹17,00,000 | ₹16,25,000 | ₹1,30,000 | 20.8% |
422
computations by two engines, and no disagreement
A second engine, written separately and sharing none of the first one's code, recomputed every one — both regimes, from ₹3 lakh to ₹2 crore. They agreed to the paisa.
11
scenarios checked by hand against the department's own calculator
Including the marginal-relief cliffs, where software most often goes quietly wrong. By hand, because a script reading a government form can read it a step behind and still look right.
₹7,800
where we disagreed with the department's estimator — and the Act agreed with us
In July 2026 the department's online estimator applied the ₹75,000 standard deduction to the old regime. The proviso to s.16(ia) confines it to the new regime; the old regime stays at ₹50,000. On the return we tested, that was a ₹7,800 difference. Every other line matched to the rupee.
And the limits of it.
What the solver proves, and what it cannot
On every return a solver checks that the return's own figures agree with one another — 56 consistency checks hold on the example above. It cannot tell whether the law was read correctly. That is what the second engine, the department's calculator and your own review are for.
Coverage
Where it works today.
Built so that each country's law is its own ruleset. A jurisdiction goes live when its law has been written down and sourced — not when a page says so.
| Status | Where | Tax | Law | Years |
|---|---|---|---|---|
| Live | India | Income tax | Income-tax Act, 1961 | AY 2022-23 to 2026-27 |
| Live | India | Income tax | Income-tax Act, 2025 | AY 2027-28 |
| Planned | India | GST | Starts from a real GSTR-2B return | |
| Next | Your jurisdiction | Tell us where you need it — write to us. | ||
Pricing
Priced by the return, not the seat.
A return is one taxpayer for one assessment year. Recomputing it — after a new document, a correction or a revised return — never counts again. Allowances run for an assessment year, not a month, because the work arrives in a season — and everyone in a firm signs in as themselves, so the record of who reviewed what stays true.
Free
Individuals checking their own return, and anyone evaluating CLAVIS on one they know.
₹0
Income tax, India · no sign-up
- Upload the documents and see both regimes computed
- Every figure with the law behind it
- Stores nothing — it computes and forgets
Practitioner
A professional in practice on their own.
₹399 a month
₹3,999 a year
or ₹3,999 a year — save ₹789
₹789 less than paying monthly
250 client-years each assessment year · One practitioner
- Both regimes computed in full on every return
- Certificates, statements and proofs read for you
- Two engines, and the check that they agree
- An evidence dossier you can print and file
- Check a figure your filing software produced
Most practices
Firm
A practice with a partner who signs and a team who prepares.
₹1,499 a month
₹14,999 a year
or ₹14,999 a year — save ₹2,989
₹2,989 less than paying monthly
1,500 client-years each assessment year · Everyone in the firm, each with their own login
- Everything in Practitioner
- A firm workspace — no client crosses firms
- A review queue ranked by what needs judgement first
- Assign work and see who holds whatIn build
- A partner sign-off trail on every returnIn build
- Bulk intake across a client bookIn build
Enterprise
Larger practices, and platforms that verify at volume.
Scoped with you
Allowance set per engagement
- The verification API for figures produced elsewhere
- A named contact for statutory questions
- Single sign-on for your organisationIn build
- Private-cloud deploymentIn build
- Notice of every rule change, with audit access to the pinned rulesIn build
Prices are for India, in rupees, before GST. Other regions open as their rules go live. More returns in a season than your plan covers? Add them in packs of 50. A feature marked In build is committed and not yet shipped; the label comes off when it does.
Manual review, or CLAVIS — with your numbers.
Every input is yours; the defaults are only a place to start. The page works out what your numbers imply. It does not claim them.
—returns go out unchecked
—less reviewer time
—lower cost
| Measure | By hand | With CLAVIS | You save |
|---|---|---|---|
| Hours to second-check every return | — | — | — |
| Cost to second-check every return | — | — | — |
| Cost per return | — | — | — |
| Returns that go out with no second check, at today's capacity | — | — | — |
| Exposure on returns that go out unchecked, on your estimates | — | — | — |
The plan pays for itself if it saves your reviewer on each return. Recomputing every return is not the same as finding every discrepancy, and CLAVIS does not claim it is.
FAQ
Answered plainly.
Including what CLAVIS does not do. A product that sells defensibility should be easiest to hold to account on its own boundaries.
Which countries does CLAVIS cover?
Income tax in India today, under the Income-tax Acts of 1961 and 2025. Each jurisdiction is its own ruleset, and the next go live when their law has been written down and sourced — not before.
Does CLAVIS file returns?
No. Keep your filing software. CLAVIS prepares an ITR-1 export for the person who files; it submits nothing.
Does the free trial keep my documents?
No. The trial computes and refuses to store a record — nothing you upload there outlives the page.
Where are records kept once I sign in?
In Mumbai (asia-south1), keyed by firm so one firm cannot read another's clients. How data is handled.
What happens if the two engines disagree?
CLAVIS will not assert the figure. It says it cannot verify it, rather than choosing one.
Can it read scanned documents?
Not by design. Text-layer PDFs only: a scanned page is reported as unread, never guessed at, because a character reader that is 95% right, feeding an exact computation, fails silently.
Does it give investment or legal advice?
No. It states statutory facts about an instrument and computes the tax effect; ranking and suitability are regulated advice. It can show what a notice turns on; replying to one is professional work.
Is the documentation grade a forecast of scrutiny?
No. It measures how well a return is evidenced, for the professional. The department's own selection rules are not public, so it is never shown to a taxpayer as a prediction.
What doesn't it do yet?
Trusts (ITR-7) are not computed, and business income from books is taken at the declared profit. Features marked In build on the plans are committed and not yet shipped.