Billkeep
Built for wherever you actually trade
Billkeep ships no country's tax rules as truth. It gives you five building blocks and does the arithmetic exactly. What the rate is, and whether it applies, stays your decision — which is the only honest place for it to sit.
Five pieces, and most systems are one of their combinations
Rates you define
A name and a percentage. VAT 20%, GST 5%, QST 9.975%, a zero rate, an exempt rate — whatever your authority calls them.
Groups of rates
Several taxes applied together, as one choice on a line. India's CGST plus SGST, Canada's GST plus a provincial tax, and anything else shaped like them.
Compound tax
A tax charged on top of a total that already includes another tax. One flag per rate, because some jurisdictions really do work that way.
Tax-inclusive prices
Enter the price the customer pays and let the tax be taken out of it, or enter the net and let it be added on. Both are normal; both are exact.
Your rounding rule
Round the tax on each line, or once on the whole invoice. Authorities disagree about this, so it is a setting rather than an assumption.
A frozen copy per document
The breakdown is written onto the invoice when you finish it. Correcting a rate next year cannot rewrite a return you already filed.
Three shapes, three answers
Added on top
| Net | £720.00 |
| VAT 20% | £144.00 |
The ordinary case: a net price with tax added.
Already included
| Price charged | £864.00 |
| of which VAT 20% | £144.00 |
Net plus tax equals the price charged, exactly — never a penny out.
Two rates at once
| Net | ₹1,000.00 |
| CGST 9% | ₹90.00 |
| SGST 9% | ₹90.00 |
One group on the line, two lines on the document.
Arithmetic that cannot drift
Money bugs are quiet. A penny lost to a rounding step does not throw an error; it just makes a total wrong on a document somebody has already sent. So the awkward part was built first, before any of the screens.
- No floating point ever touches money. Amounts are whole minor units — pennies, cents, paise.
- Rates are held to a millionth of a percent, because 9.975% cannot be written in basis points.
- Quantities go to three decimals, so 1.5 hours is 1.5 hours.
- Intermediates stay exact fractions until one deliberate rounding step at the end.
- A discount on the whole invoice is spread back across the lines by largest remainder, so the parts still add to the whole.
Whatever combination of discounts, inclusive prices, compound rates and rounding rules you choose, the line figures always sum to the invoice total. Not to within a penny. Exactly.
There is a test suite whose entire job is to fail if that stops being true — on the phone and in the browser, so the two can never disagree about a total.
The number you need, and where it comes from
Tax charged, broken down by rate, over a period you pick. Read from each document's own frozen breakdown, so it reports what was actually charged rather than what today's settings would charge.
- Dated by issue date — the tax point in most places, and the only date every document has.
- Drafts never count. Nobody has seen them.
- Cancelled documents never count, even though their number stays spent.
- Quotes never count. An offer is not a sale.
- Credit notes subtract, so a return is not overstated.
- One currency at a time, because a mixed total is a meaningless number.
Billkeep does not know your tax rules
It says so on the totals screen, and it is worth repeating here. This is arithmetic and record-keeping, not advice. Which rate applies to what you sell, whether you should be registered, and when a return is due are questions for your tax authority or your accountant. Billkeep's job is to make sure that once you have decided, the numbers are right and stay right.
Set your rates up once
It takes about a minute, and after that every invoice picks the right one from a list.