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Numbers (Numbers) in Contracts and Specifications

By Kevin O'Beirne, PE, FCSI, CCS, CCCA, CDT posted 01-06-2020 17:59


Editor's Note: CSI is pleased to publish this seventh blog from Kevin O’Beirne, PE, FCSI, CCS, CCCA, CDT. If you have an idea or opinion you would like to share with your colleagues in the construction industry, please contact CSI Content Strategist Peter Kray at He would love to help publish your thoughts.


A common practice in contracts, specifications, and other documents is a tendency by some people to write almost every number twice in a row: “ten (10) spare filters,” “thirty (30) days,” “five-hundred dollars ($500)”, and so on. Perhaps nowhere is this practice more accepted and used than in bid forms, which frequently require that bidders indicate each amount twice.


What is the basis for this practice? Is it a good idea?


Its basis is unclear, but probably started hundreds of years ago when some attorney decided that a handwritten number could be misinterpreted or its ink smudged, thus giving rise to disagreements about the quantity, number, or amount indicated by the document.   


Perhaps another reason why numbers are often written twice each in contracts and specifications is older technology for document reproduction. Mimeographs, faxes, and even photocopying are not foolproof and can result in smudges and legibility problems. Thus, when a number was indicated, perhaps prudence dictated being “extra clear” about the intended quantity, amount, or number.


In the modern environment of computers, scanners, and digital documents, however, all that seems inapplicable and unnecessary. Thus, is the practice of writing “sixty (60)” still a good idea?


When I shared a draft of this post with an attorney experienced with construction contracts and professional services agreements, he broke into a cold sweat. He nervously explained that the reason why modern lawyers still often write, “five (5)” and the like is because overworked professionals, like attorneys, architects, and engineers, sometimes type things hastily and without back-checking. He argued that, in the event of a numerical typo—such as a couple extra, inadvertent zeroes added ahead of a decimal—an adjacent number-expressed-with-words correctly indicated the intended number and thus provided grounds for a counter-argument or defense. While that may be the modern reason for indicating numbers twice each, it presumes a basic lack of quality in document preparation. It also makes the document more difficult to read and may introduce other problems.


The Construction Specifications Institute espouses an excellent contract- and specifications-writing axiom: “indicate it once and in the right place.” The reason for indicating a requirement only once is to reduce the potential for a subsequent modification that changes only one location of a repeated requirement, thus resulting in conflicting contractual requirements. Writing each number twice violates this axiom and introduces potential for contracts. Obviously, conflicts in contracts and specifications are undesirable. To address my attorney-friend’s concerns, if you indicate a requirement—like a number—only once, you really need to be sure it is correct.


In accordance with CSI’s axiom, the standard contract documents of both the American Institute of Architects (AIA) and the Engineers Joint Contract Documents Committee (EJCDC) each indicate numbers only once. Even EJCDC’s model bid form (EJCDC C-410) and design-builder price proposal form (EJCDC D-425) require that bidders and proposers indicate their pricing using only numerals. Undoubtedly, careful indication is implied.


Presented below is advice on indicating numbers in specifications, contracts, and other documents:

  1. Indicate each number only once.
  2. Indicate numbers less than 10 using words, where appropriate, such as “seven days.” On drawings, typically only numerals are used, for brevity.
  3. Indicate numbers greater than nine using numerals: “10,” “26,” “365.”
  4. When a number starts a sentence, write the number in words regardless of its value: “Fifty-two weeks comprise a year.”
  5. Cross-references to other provisions are proper nouns and should be written exactly as indicated regardless of the number; thus, “Paragraph 6” instead of “Paragraph six.”
  6. In tables, numerals are often preferred instead of numbers-indicated-in-words. However, the number zero is often more clear when written as a word.
  7. When two numbers must follow each other in succession, one should typically be written in words: “Submit six 4-inch by 6-inch photographic prints.”
  8. For fractions, typically avoid indications such as “½” and “¼”—which can be difficult to read, especially when a document is canned—in favor of “1/2” and “1/4” and the like. Often, decimals may be more clear than fractions, because the dash commonly used to link a fraction with a whole number, such as “2-1/2” could possibly be interpreted as “two minus one-half”; instead, “2.5” is more-clear.  However, in some cases, common fractions, such as “7/8” or “3/16” may be more-readily understood than their decimal counterparts (respectively, “0.875” and “0.1875”), so using a dash to link whole numbers and fractions (“1-3/8”) will probably never go out of style.


In summary, the sticky old practice of indicating each number twice, “ten (10)” may lead to conflicting requirements and should, optimally, be avoided. Be clear about how numbers are indicated in specifications, contracts, correspondence, and other documents, and—by the way—be sure to indicate the number correctly.



Copyright 2019 by Kevin O’Beirne

The content of this blog post is by the author alone and should not be attributed to any other individual or entity.


Kevin O’Beirne, PE, FCSI, CCS, CCCA is a professional engineer licensed in NY and PA with over 30 years of experience designing and constructing water and wastewater infrastructure for public and private clients.  He is the National Manager of Engineering Specifications for a global engineering and architecture design firm.  He is a member of CSI’s MasterFormat Maintenance Task Team and is the certification chair of CSI’s Buffalo-Western New York Chapter.  He is an ACEC voting delegate in the Engineers Joint Contract Documents Committee (EJCDC) and lives and works in the Buffalo NY rea.  Contact:




Kevin's recommendation at the end is the most important part of his discussion.  He is right in line with my thoughts and practice on displaying numbers.  The dual # and text never made any sense to me.  My learning curve on this goes back to High School English composition.  From the contractor ​view I agree with Lee.  The less confusion in the field the better.  Ron
Lee--Thanks very much.  I'm not sure, however, if it's right to pre-judge the quality of a spec or other document just because the writer used the very-common approach of saying some of the numbers twice: "five (5)".  People can be creatures of habit and, when you see others doing this with numbers, it's easy to fall into the habit of doing the same thing yourself..  One purpose of this blog post was really to get reads to think about why they write numbers the way they do.

01-07-2020 14:19

I agree with you! When I see specs with the numbers and the words, I use that as an indication that the documents probably have other specification writing issues.