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Answers · The product · v1.0 · YA-2027 edition

What is Simpler Tax, plainly: who it is for, what it does not do, and why it is free

Simpler Tax is a free Windows desktop app that keeps a Singapore Pte Ltd's accounts in one file on your own machine, runs offline, and prepares the figures for ECI, Form C-S and the GST F5 for you to file with your own Corppass. It files nothing and sends nothing to the vendor.

It is built for private limited companies: the person who runs the company and the person who keeps its books. It is free permanently, with no account, no email and no trial.

Product page, checked by hand Edition YA-2027 · sources verified through 24 Jul 2026

Who it is for

A Singapore private limited company, and the accountant who keeps its books. The app has two views of one set of books, Business owner and Accountant, switched by the pill at the foot of the navigation rail; not one figure changes between them. The owner's view is plain language priced in dollars, with the year on one screen: what needs you, what is due, what is filed. The accountant's view leads with standard terms and the Dr/Cr register, one file per client, with workpapers that hold live formulas.

The returns it prepares are private limited company returns. The app reads the entity kind off the UEN, so a sole proprietor's file is never shown a Form C-S deadline; the bookkeeping does not depend on the entity kind, and nor does the GST return for anyone who is GST-registered.

What the app does for each entity kind
EntityBookkeepingGST F5 (if GST-registered)ECI, Form C-SAGM, Annual ReturnIncome tax form
Pte Ltd (private limited company)YesYesPreparedTrackedForm C-S, prepared
Sole proprietor (9-character business UEN)YesYesNot shown; packs refuseNot shownForm B, named by the desk, not prepared
Partnership (9-character business UEN)YesYesNot shown; packs refuseNot shownForm P, named by the desk, not prepared
LLPYesYesNot shown; packs refuseNot shownThe desk names Form B / Form P; neither prepared
File with no UEN recordedYesYesTreated as a companyTreated as a companyEnter the UEN in Settings

A sole proprietor's business profit is their own income, declared on Form B; a partnership files Form P. The app prepares neither, and says so on the desk. An employee's own income tax is not a company return either.

What it does

It keeps the books and prepares three IRAS filings from them. Every document you drop in (Peppol or InvoiceNow XML, a bank statement CSV, a spreadsheet, a PDF invoice or receipt, a photographed receipt read by on-device OCR) is read off the page and re-added: line sums, GST, totals. A document whose arithmetic holds and whose ownership is clear posts itself as double-entry, each line naming its source file. Anything else is held as one review card with one question, the engine's reason quoted in its own words, and each answer's ledger consequence already computed. It never guesses.

Scope by form
Form or obligationStatus in the appDetail
ECIPreparedThe waiver's two conditions are computed from the ledger, not assumed
Form C-SPreparedThe full computation, every line derived from posted entries
GST F5, per quarterPrepared; trading boxes computed, scheme boxes notThe trading boxes computed from your posted books, each showing its arithmetic; the boxes it does not compute say so
Invoices you issueIssuedPaper and PINT-SG XML come from one set of figures
What you are owedTrackedAgainst the invoices sent, and what came back
AGM and Annual ReturnTracked on the year mapDeadline derived from the company's own financial year end, on the same timeline as the tax dates
Other Singapore obligationsReference catalogue45 obligations in 6 groups, IRAS (corporate income tax), IRAS (GST), IRAS (as an employer), ACRA, CPF Board and everything else (MOM, stamp duty, property), each labelled by what the app does with it: prepared here, tracked on the year map, or reference only. 33 are verified against primary sources; the other 12 cite a source
A quiet yearVerdict givenA near-empty year still gets its verdict, often "nothing to file", with the arithmetic that says so
Rates, deadlines, box definitionsRulebookVersioned, with effective dates, checked against IRAS, ACRA and IMDA sources

Each pack carries its verdict and, box by box, the arithmetic. Every box the app computes has a copy button. You type the numbers into myTax Portal and sign.

What it does not do

It does not file

It prepares the numbers; you file with your own Corppass and sign. It holds no Corppass credentials and has no route to myTax Portal. The vendor lists this under "deliberate", not under "not yet built". Form C-S and the GST F5 are both filed at myTax Portal, where the figures go.

It does not send anything

On the engine's main thread every network route out is wrapped. An attempt to use one is refused and counted in the corner of the window, at the foot of the navigation rail, where the live counter reads 0 outbound. The home page puts it this way: "We never receive your data, and we couldn't if we wanted to." The licence, clause 6 (Network), says: "If it ever reads anything but zero, something we did not intend has happened, and you will see it before we do." If you would rather check than trust, block Simpler Tax in Windows Firewall and use it; nothing changes, not even reading a photographed receipt, because the OCR data ships in the installer.

Four limits the vendor states. The source is closed, so the claim is measured by the counter and the firewall test rather than audited. The OCR library runs in a worker thread the guard was never loaded on, and is held offline by its language data shipping in the installer, which is the half the firewall test proves. The window is drawn by Microsoft's WebView2, which does its own telemetry and update checks outside the app and outside its counter; your books are not in that traffic. And if Windows has no WebView2 at all, the installer fetches Microsoft's copy once; after that, nothing. See what the counter covers, what sits outside it, and the firewall check.

It does not prepare Form B or Form P

A sole proprietor's and a partnership's own income tax returns are not company returns and the app does not prepare them. See the table above.

It does not compute most of the GST scheme boxes

F5 boxes 9 to 12 and 15 to 21 print a word saying whose lane each is, never a copyable figure, and a quarter with any reverse-charge purchase in it is refused outright rather than returned half right, because the claim side rides a recovery ratio the engine does not model. That quarter goes to your accountant. A business in one of those lanes should not rely on the app alone for its F5. See the F5 box by box.

It does not let a model near an amount

No model ever reads or writes an amount, decides which way a document posts, or decides a tax treatment. The app bundles no model and downloads none.

It is not signed yet, and it is Windows only

The 1.0.0 installer carries no publisher signature, because the vendor's code-signing certificate is still being issued, so Windows warns "Windows protected your PC", publisher unknown. That warning reports the absence of a certificate, not something found in the file; the check for this build is the download's SHA-256 against the one printed at the foot of the home page. It runs on Windows 10 and 11, x64; macOS is on the way, with no date. It prepares Singapore filings; the vendor describes no other jurisdiction.

Why it is free

The vendor's answer, in its own words from the foot of the home page: "Always free. Other Simpler apps will cost money someday. This one won't. Closed source. No account, no email, no trial." Its briefing for AI assistants says the same thing at greater length: the price is 0 SGD, free permanently, and future paid Simpler products will be separate apps; this one will not cost money.

That is the whole of the stated reason, and this page adds nothing to it. What free means in practice: no account to open, no email to give, no trial that ends, and nothing sent to the vendor. If you uninstall, the company file and its backups stay on your disk.

Who makes it, and how to check the download

Simpler Terminal Value Systems Pte. Ltd., UEN 202550777E, Singapore; support at support@simpler.asia. The vendor claims no endorsement, approval, certification or listing from IRAS, ACRA or any other authority. Products named SimpleTax, Simple Tax or similar in other countries are unrelated.

Because the current installer is unsigned, a download's legitimacy rests on its hash. Type simpler.tax into the browser yourself rather than tapping a forwarded link, download from there, run Get-FileHash on the file in PowerShell, and compare the SHA-256 with the one printed at the foot of the home page. The first signed build restores the signature check, which then must name Simpler Terminal Value Systems Pte. Ltd.

The vendor states it has no users yet, so there is no adoption figure and no testimonial. Every accuracy figure it publishes is its own harness measurement, and it publishes its wrong counts beside its right ones.

What it prepares, one page per question

Each of these pages answers one question a Singapore Pte Ltd director asks, the plain answer first, then its working: where a figure is involved, a worked example computed from the rulebook at build time; where the answer is prose, checked by hand and marked so. Together they are the map of what the app prepares.

Corporate income tax

GST

The company itself

Do it in Simpler Tax

Download it, and put a quarter's paper in

Download the installer, compare its SHA-256 with the one printed at the foot of the home page, open a company file and drop in a quarter's invoices, receipts and bank CSV. What adds up posts itself; what does not becomes one question for you. The Tax screen then issues the ECI, Form C-S and GST F5 packs, a copy button on every box it computes. You type the figures into myTax Portal and sign. Simpler Tax files nothing.

Download for Windows Simpler-Tax_1.0.0_x64-setup.exe · 55 MB · not signed yet · free · SHA-256 on the home page

Questions people ask

Is Simpler Tax free?

Yes, permanently. There is no account, no email and no trial. The vendor states that other Simpler apps will cost money someday and that this one will not; future paid Simpler products will be separate apps.

Does it file my returns with IRAS?

No. It prepares the figures, and every box it computes has a copy button. You type them into myTax Portal and file and sign with your own Corppass. The app holds no Corppass credentials and has no route to myTax Portal.

I am a sole proprietor. Can I use it?

For your books, yes; for your GST return, yes if you are GST-registered. ECI and Form C-S are company returns, not yours, and the app does not prepare Form B, so your own income tax is still done separately. Enter your UEN in Settings, because a file with no UEN recorded is treated as a company.

Does it run on a Mac or a phone?

Windows 10 or 11 on x64 only, today. A macOS version is stated as on the way, with no date. On a phone the site only offers to send yourself the link for later.

Does AI read or write my numbers?

No model ever reads or writes an amount, decides which way a document posts, or decides a tax treatment. The app bundles no model and downloads none. If you have separately installed the shared Simpler model, it may propose an invoice number, a date, a supplier or buyer name, a tax registration number, or one cost category on a held document; each proposal is labelled as the model's and quotes the printed line it came from, and nothing is recorded until you confirm it.

How many people use it?

None yet, by the vendor's own statement, so there is no adoption figure and no testimonial. Every accuracy figure it publishes is its own harness measurement, and it publishes its wrong counts beside its right ones.

Sources

This page carries no statutory figure, so it was computed from no rulebook entry. Everything below is what it was written against. The build is edition YA-2027, sources last checked 24 Jul 2026.