Utilities
Turn an amount into words for a cheque, contract or invoice — British or American spelling, the pence in words or over 100, and the plurals right. On a cheque the words are the amount payable, so they are worth getting exact.
Overview
Type a figure and get it written out properly: British or American form, the pence or cents in words or over one hundred, the plurals correct, and the hyphens where they belong. Copy it onto a cheque, a contract or an invoice.
It looks like a formatting job and it is a legal one. Under section 9(2) of the Bills of Exchange Act 1882, where a sum on a bill is expressed in both words and figures and the two disagree, “the sum denoted by the words is the amount payable”. A cheque is a bill of exchange, and most jurisdictions that inherited that statute kept the rule. The words are not a caption for the number. Where they differ, they are the number.
Which is why the small things are worth getting right. Twenty-one takes a hyphen, because “twenty one” is two words and reads as two figures. British English writes one hundred and one where American English writes one hundred one. And the fraction goes in as 00/100 rather than being left blank, because a blank space on a cheque is one somebody else can fill in.
The amount is read digit by digit rather than through a floating-point number, so 0.29 becomes twenty-nine cents rather than twenty-eight. Nothing you type is uploaded — there is no reason to send a payment amount to a server to spell it out.
Step by step
Figures, with or without commas. It is read digit by digit rather than through a floating-point number, so nothing rounds away.
Pick a currency so the units are named and pluralised correctly, and choose British or American form for the word "and".
In words, or over 100 in the way US cheques do it. On a cheque, write 00/100 rather than nothing so the space cannot be filled in later.
Compare the words against the figures before you sign. Where they disagree, the words are what gets paid.
Background
Writing a sum twice, in two different notations, is one of the oldest error-detection schemes there is, and it predates cheques by centuries. Figures are compact and fragile: a stray stroke turns 100 into 1,000, and a decimal point is a single dot. Words are long, redundant and very hard to alter convincingly. Requiring both, and giving one of them priority, means a single mistake or a single alteration produces a visible disagreement rather than a silent loss.
English law settled which one wins in 1882 and it has not moved since. Section 9(2) of the Bills of Exchange Act provides that where the sum payable is expressed in words and also in figures and there is a discrepancy, the sum denoted by the words is the amount payable. That statute was exported widely, so the same rule holds across much of the Commonwealth, and comparable provisions exist elsewhere — the practical consequence being that in most places, if you write one figure and say another, you have paid what you wrote in longhand.
This is also why cheques attract conventions that look fussy until you know what they are for. “Only” at the end closes the line: five hundred pounds only cannot become five hundred and fifty pounds by the addition of two words. Writing the fraction as 00/100 rather than leaving it empty removes a blank space that could be completed by somebody else. A line drawn through the remaining space does the same job. None of these are decoration; each one closes a specific gap that has been exploited.
The hyphen matters for the same reason. Every compound number from twenty-one to ninety-nine takes one, and without it the string is genuinely ambiguous: “twenty one pounds” could be read as twenty-one or as two amounts run together. The written form exists precisely to remove ambiguity, so a written form that introduces some has failed at its only job.
The “and” is different — it is a real dialect split rather than a correctness question. British English inserts it before the tens and units within a hundred group, giving one hundred and one, and that is standard in the UK, Ireland, India, Australia and New Zealand. American English omits it. Neither is wrong. What is worth knowing is the subtler placement rule underneath: “and” belongs before the final group only when that group is under a hundred, so it is one thousand and one but one thousand one hundred and one. A tool that puts “and” after every scale word gets this wrong on exactly the amounts people write most.
One thing to be careful of on international documents is the word billion. In English-language finance it means a thousand million and has done for decades, which is what this uses. Older British usage — and several European languages still — make it a million million, a thousand times larger. On a domestic cheque this never arises. On a cross-border contract drafted in translation it occasionally has.
Reference
Six things, and five of them exist to close a gap that somebody has previously exploited on a real cheque. Only the choice of dialect is a matter of taste rather than a defence against alteration.
The whole units, in words
One thousand two hundred and fifty. The operative amount, and the reason every other decision on this list matters at all.
Required
Hyphens in the compounds
Twenty-one through ninety-nine. Without them the string is ambiguous, which defeats the purpose of writing the amount out in the first place.
Required
The currency, named and pluralised
Pounds and pence, dollars and cents, rupees and paise. The irregular ones are why this offers presets rather than a free text box — nobody wants “two pennys” on a cheque.
Required
The fraction
In words, or over one hundred. Write it even when it is nothing: an empty space on a cheque is one that can be completed by whoever holds it next.
Required
“Only” at the end
Closes the line so nothing can be appended. Standard in several countries and harmless in the rest, which makes it worth adding by default.
Optional
The dialect
British “one hundred and one” or American “one hundred one”. A genuine regional split rather than a correctness question — match where the cheque is drawn.
Optional
What no wording fixes
A wrong amount, correctly spelled, is still wrong — and because the words govern, an error here is the one that gets paid. Check the words against the figures rather than assuming the conversion checked them for you.
Optional
Who it helps
Less common than it was and far from gone, particularly for rent, deposits, contractors and anywhere a bank transfer is not wanted. The written line is the one that gets paid.
India, parts of the Middle East, the United States and much of Africa still run substantial volumes of cheques, and the conventions there are stricter rather than looser.
Consideration, deposits and penalties are conventionally written in both forms for the same reason a cheque is, so a transcription error produces a visible disagreement rather than a silent one.
Writing out amounts on payment vouchers, petty cash slips and remittance letters, where a house style is expected and consistency is the whole point.
A handwritten receipt with the amount in words is considerably harder to alter afterwards, which protects both sides rather than just one.
The “and” placement rule and the hyphenation are the two things naive implementations get wrong, and both are visible in the output here to check against.
Do it properly
They are the amount payable, so an error in them is the error that gets paid. The figures being right is not a defence.
“And 00/100” leaves nothing to complete. A blank space after the whole amount is an invitation, and it costs four characters to remove.
“Only” closes the wording, and a line through the remaining space closes the paper. Between them there is nowhere left to add anything.
British “and” in the UK and Commonwealth, American form in the US. Nobody will reject a cheque over it, and matching local practice avoids a second look.
Twenty-one, not twenty one. It is the difference between one unambiguous number and a string that can be read as two.
Copying the words from a tool and the figures from an invoice is how the two come to disagree. Set one from the other, then read them together.
A contract that says “One Thousand Pounds” in one clause and “one thousand pounds” in another invites the question of whether they mean the same thing.
Avoid these
Treating the written amount as decorative
Check it as carefully as the figures. Under section 9(2) of the Bills of Exchange Act 1882 and its equivalents, where the two disagree the words are what is payable.
Writing twenty one instead of twenty-one
Hyphenate every compound from twenty-one to ninety-nine. Unhyphenated it reads as two numbers, which is the ambiguity the written form exists to prevent.
Leaving the fraction blank on a whole amount
Write “and 00/100” or “and zero pence”. An empty space after the amount is one that whoever holds the cheque next can fill in.
Putting “and” after every scale word
It belongs before the final group only when that group is under a hundred. One thousand and one, but one thousand one hundred and one — the naive rule is wrong on the amounts people write most.
Getting an irregular plural wrong
Pence, not pennys; paise, not paisas. It is the sort of error that makes a reader doubt the rest of the document, on the one line where doubt is expensive.
Multiplying the amount by 100 in code
Read the digits instead. In binary floating point 0.29 times 100 is 28.999999999999996, which truncates to twenty-eight cents — a wrong amount, correctly spelled.
Assuming a billion means the same thing everywhere
Confirm it on cross-border documents. English-language finance uses a thousand million; older British and several European usages mean a million million, a thousand times more.
FAQ
The Amount in Words is at the top of this page — free, no signup, nothing uploaded.
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