Writing Numbers in Legal Documents and Contracts
Last updated 24 August 2026
Contracts and cheques often state an amount twice — “five thousand dollars ($5,000)”. Writing it in both words and figures is a long-standing anti-fraud practice: a stray digit is easy to alter, a spelled-out amount is not.
The habit predates typewriters and survives for a simple reason. Changing $5,000
to $45,000 takes one pen stroke and leaves little trace. Changing five thousand
dollars to forty-five thousand dollars requires rewriting a line of prose in
someone else’s hand. The redundancy is the security.
Which form controls
If the words and the figures disagree, most legal traditions treat the words as controlling. This rule appears, for example, in negotiable-instruments law for cheques. The practical takeaway: make the two forms match exactly before signing, and fix any mismatch rather than relying on the rule.
Two cautions about leaning on it. First, the rule is a tie-breaker for genuine ambiguity, not a licence to be careless — a court reading an obvious clerical error may look at the surrounding agreement rather than apply the rule mechanically. Second, banks processing cheques at volume increasingly read the numeric field by machine, so a mismatch in practice often means rejection or a manual review rather than payment of the written amount.
How to write it well
- Spell the amount in words first, then put the figure in parentheses.
- Capitalize consistently and avoid mixing styles.
- For currency, include the unit: “five thousand dollars”, not just “five thousand”.
- Put the currency code where more than one currency could be meant: “five thousand US dollars (USD 5,000)”.
- Do not repeat the duplication for every number in the document — reserve it for amounts, terms and quantities that matter.
Conventions worth following
Consistency beats correctness. If the agreement writes Twenty-Five Thousand Dollars ($25,000) in one clause, it should not write twenty five thousand dollars (25,000) in the next. Inconsistent formatting is what makes a document look altered even when it has not been.
Hyphenate properly. Compound numbers from twenty-one to ninety-nine take a hyphen — Twenty-Five, not Twenty Five. This is ordinary English spelling and its absence in a formal instrument reads as sloppiness. See the spelling guide.
Watch the “and”. In American drafting, one hundred forty-two dollars has no “and” inside the number. British drafting inserts one. Either is fine; switching between them within a document is not.
Dates in full. Numeric-only dates are ambiguous across jurisdictions — 05/01/2026 is 5 January in London and 1 May in New York. Write the month as a word in any document that crosses a border.
Percentages and interest. The same duplication applies and matters more, because a misplaced decimal in a rate compounds: five percent (5%) per annum.
Where duplication does not belong
Do not spell out numbers that are labels rather than quantities — section numbers, clause references, addresses, account numbers. Clause 12 stays Clause 12. Spelling those out adds no security and makes cross-referencing harder.
Likewise, tables of figures — schedules of payments, price lists — are normally left in figures throughout. Duplicating every cell in words would make the table unreadable, which is its own kind of risk.
Time periods and notice clauses
Amounts are not the only numbers worth duplicating. Notice periods, deadlines and terms are where disputes actually start, and they carry the same risk of a transposed digit: thirty (30) days rather than 30 days. Where a period could be read two ways, say which — thirty (30) calendar days and ten (10) business days are not the same obligation, and the difference has ended more than one argument about whether a notice was served in time.
Ages, quantities and share counts follow the same logic. A schedule that reads five thousand (5,000) ordinary shares cannot be quietly turned into fifty thousand by adding a zero.
Before you sign
Read the words and the figures as two separate documents. Check each amount against the other, check that every duplicated pair actually matches, and correct mismatches on the face of the document by re-executing rather than by amending in ink.
Use the converter to generate the exact words for any amount, or read our guide to writing a check.