Google Forms number validation

Last updated September 2026 · ~10 minute read

Short answer: Number is one category of Response validation, and among the text question types it is offered on Short answer only — Paragraph gets Length and Regular expression and nothing else. There are ten Number rules. Google’s help page does not print their names: it says only to select Number and then “select one of the options for your rule.” The complete set is documented elsewhere by Google, in the Apps Script reference for Forms, and is listed in full below.

This page is about the Number family on its own — the rules that make a form refuse anything that is not a number in the range you want. For the other categories, see Google Forms data validation; for pattern rules, Google Forms regex validation.

Where the Number rule lives, and why it is Short answer only

Google’s click-path, from How to set rules for your form: open a form, click Add, choose the question type, click More, then Response validation. Then, in Google’s words, “select first the type of rule you want. The rule options available depend on the type of question chosen.”

That last sentence is the whole story for Number. The rules page is organised into exactly five sections — Rules for short answer questions, Rules for Paragraph questions, Rules for checkboxes questions, Rules for Multiple choice grid questions and Rules for Checkbox grid questions — and Number appears under the first one alone. The Short answer section lists Number, Text, Length and Regular expression. The Paragraph section lists Length and Regular expression, and stops.

So a Paragraph question cannot be constrained to a number, and neither can anything else. A question that should hold a quantity, an age or a price has to be a Short answer — and there is a trap in converting one late, which is in the last section of this page.

The ten Number rules

Most pages on this topic present the list as if Google printed it. Google does not. The help page’s entire treatment of the category is: “Number: To ensure the answer contains a certain number, in the drop down menu, select Number. Then, select one of the options for your rule.” It gives two examples and no list: “A number greater than or equal to 50” and “A number between 21 and 42”.

The complete set is published by Google, in the Apps Script reference for Forms. The class TextValidationBuilder defines one method per rule, and ten concern numbers. The middle column below quotes Google’s own one-line description of each. The right-hand column is the wording Forms+ puts in its operator menu: Google publishes no drop-down labels anywhere, so treat the rules as Google’s and the labels as the app’s.

Two details repay a second look. Between and Not between are inclusive — Google’s word, in both entries — so Between 1 and 100 accepts both 1 and 100. And Is number sets no bound at all: it rejects “about forty” and accepts −9,999,999. It is the right rule only when you had no range in mind.

The custom error message

Google documents one optional field alongside the rule: “To add an error message, on the right, in the ‘Custom error text’ field, enter an error message. Responders will get this message when their answer doesn’t follow the rules.” Its published example is You reached the limit of 200 words. That is everything Google publishes about it — no length limit, no formatting, no placeholder for the value you set.

Write one anyway, with the actual numbers in it. A responder blocked without being told the range has to guess, and the usual guess is that the form is broken.

Decimals and negatives: what Google actually documents

Very little, and it is better to say so than to invent a rule. Neither the word decimal nor the word negative appears anywhere on Google’s rules page. Two published facts do bear on the question:

• Whole number is a separate rule from Is number. Google defines requireWholeNumber as “Requires text item to be a whole number” and requireNumber as “Requires text item to be a number”, as two distinct methods. The existence of both is the documentation that “a number” is the wider set — which is exactly why a range rule on its own does not reject 42.5.
• The bound you type is not restricted to an integer. In the same reference, the arguments to the number rules are typed Number, while the arguments to the character-length rules are typed Integer. Google’s own reference therefore does not require a Number rule’s bound to be whole.

What Google never defines is which values count as “whole”, so whether −3 satisfies a Whole number rule is not answerable from the documentation. Nor does anything published say how a minus sign, a thousands separator or a decimal comma is parsed for a responder whose locale writes numbers differently. If your form depends on any of that, open the live form, submit the awkward value and read what happens.

“A whole number from 1 to 100” is two rules, and you get one

This is the single most common disappointment in the Number family. A question carries one rule row. Between 1 and 100 accepts 42.5. Whole number accepts 4000000. Google documents no way to combine two rules on one question, and there is no compound “whole number between” option in the ten.

Three honest choices. Pick the failure that actually costs you something and name the other half in the custom error text — usually the right answer. Or use Regular expression, one rule that expresses both at once: ^(100|[1-9][0-9]?)$ is 1–100 with no decimals. Google never names the regex dialect it runs, so test that pattern in the live form rather than trusting it. Or stop validating and start offering.

When the number comes from a fixed set, offer it instead

A rule that rejects bad input is second best to an input that cannot be bad. If the acceptable answers are a short, known list — a rating from 1 to 5, a party size, a year group, a number of tickets — a Dropdown or Multiple choice question removes the problem. Neither type accepts response validation, and neither needs it: a responder cannot mistype an option they did not type. No decimal to reject, no minus sign, no locale to parse, no error message to write.

The trade is that you fix the set at build time. The dividing line: Number when the range is wide or open-ended, a choice list whenever you could write every valid answer down in a minute.

What a Number rule does not do

Response validation runs in the responder’s browser as they submit. It is a typo filter, and a good one — it catches the transposed digit, the phone number typed into the age box, the word “twenty” where you needed 20. It is not a guarantee about your data, and three limits are worth stating plainly.

• It cannot tell a valid number from a true one. Between 18 and 120 on an age question is satisfied by 19 typed by a forty-six-year-old, and a figure pasted from the wrong row of a spreadsheet is still in range. Every rule here constrains the shape of an answer, never its truth.
• It does not change what the spreadsheet stores. Here Google is silent. Its page on where form responses are saved says only that “If you store your responses in a spreadsheet, Google Sheets automatically puts your data in a table. It gives your data format and structure.” No Google Forms documentation states what cell type a validated number lands in, and nothing promises that adding a Number rule makes the destination cell numeric. We are not going to assert one on Google’s behalf. If a formula, a chart or an export depends on the value being a number rather than text, submit one real response and check the cell in the sheet.
• It is not in the public API. The word “validation” does not appear once in Google’s Forms REST API reference for forms — which is why anything that sets these rules programmatically goes through Apps Script instead.

The consequence applies to every validation category: use the rule to make the honest responder’s life easier, and check the values again wherever the data lands if a wrong one costs you money.

Setting a Number rule from a phone

The question’s three-dot menu is the first casualty of the Google Forms editor on a phone browser, and it is the only way in to Response validation. Forms+, a native iPhone and iPad client for your real Google Forms, keeps that entry on the question card for the three types that take a rule — Short answer, Paragraph and Checkboxes — with the same ten Number operators and the same Custom error text field, writing to your own Google account.

One warning worth carrying into either editor. In Forms+, changing a question’s type clears that question’s validation unconditionally — the rule is not migrated. The editor’s Undo button reverses the whole type change, rule included, but only until you save: a successful save clears the undo history, and after that re-adding the rule is the only way back. Google does not document what its own web editor does on a type change. Since Number is Short-answer-only, the common sequence is to build the question, find the type is wrong, change it, and lose the rule set five minutes earlier. Settle the type first; add the rule last.

A pre-publish Audit form pass also flags any text question with no response validation whose title mentions a number, phone, email, URL or postcode.

Frequently asked questions

How many Number validation rules does Google Forms have?

Ten. Google’s help page does not print their names — it says only to select Number and then “select one of the options for your rule”. The set is defined in Google’s Apps Script reference, where TextValidationBuilder documents nine requireNumber methods plus requireWholeNumber: greater than, greater than or equal to, less than, less than or equal to, equal to, not equal to, between, not between, is a number, and whole number.

Which question types can use Number validation?

Short answer only. Google’s rules page has five sections — Short answer, Paragraph, Checkboxes, Multiple choice grid and Checkbox grid — and Number appears under Short answer alone. Paragraph gets Length and Regular expression and nothing else.

Does Google Forms number validation allow decimals and negatives?

Google does not document it. Neither the word decimal nor the word negative appears on its rules page. What Google does publish is that a whole-number rule exists separately from an is-a-number rule — which is why a Between rule on its own does not reject 42.5 — and that the bounds you pass to a number rule are typed Number rather than Integer. Anything more precise has to be tested in the live form.

Does a Number rule make the spreadsheet cell a number?

Google is silent on this. Its page on where responses are saved says only that Google Sheets “automatically puts your data in a table” and “gives your data format and structure”. No Forms documentation states the cell type a validated number lands in. If a formula depends on the value being numeric, check a real response in the sheet.

Why did my validation rule disappear?

Most often because the question type changed. In Forms+, changing a question’s type clears that question’s validation unconditionally. Google does not document what its own web editor does on a type change. Either way, settle the question type first and add the Number rule last.