Fix Formatter “Only numeric values are allowed” error in Zapier

When you work with numbers in Zapier, you may see the Formatter error message “Invalid Syntax: Only numeric values are allowed”. This guide explains why the error appears and shows step-by-step how to fix it so your automations run smoothly again.

What this Zapier Formatter error means

This specific error comes from the Formatter by Zapier app when it expects a numeric value but receives something else. The error text usually looks like:

Invalid Syntax: Only numeric values are allowed
Or a similar message about invalid numbers

It appears during a Zap run when a step tries to perform a math operation, format numbers, or work with currency using non-numeric input.

Common causes of the error in Zapier

The Formatter error occurs when the value passed into a step is not a valid number for the action type. Typical causes in Zapier include:

Text instead of numbers, such as ten instead of 10
Currency symbols, like $10.50 instead of 10.50
Thousand separators or formatting, such as 1,000 or 1 000
Additional characters, like spaces, letters, or punctuation
Blank values, placeholders, or unexpected input from a previous step

Whenever the Formatter by Zapier step cannot convert the incoming value into a clean number, it raises this error.

How to find where the Zapier error happens

Before you can fix the problem, you need to pinpoint which step in your workflow is failing. Follow these steps inside your Zapier editor:

Open the Zap that shows the error in its task history.
Go to the Task History or Zap runs page.
Click the failed run that shows the Formatter error.
Look for the step labeled Formatter by Zapier with a red error icon.
Open that step to see the Input Data and the full error message.

The input values displayed here show exactly what Zapier tried to parse as a number and which field triggered the issue.

How to fix “Only numeric values are allowed” in Zapier

Once you know which field is causing trouble, you can adjust the Formatter by Zapier step so that it receives valid numeric values. Use the following methods depending on your scenario.

Method 1: Clean up the source field in Zapier

If the problem comes from the app that sends data into the Formatter step, try fixing the value at the source:

Edit the trigger or action step that outputs the number.
Check the specific field mapped into the Formatter step.
Confirm that field is actually numeric in the source app (for example, a price, quantity, or total).
If the source app offers a number only field instead of a text field, map that one instead.

This approach ensures Zapier receives numbers in a consistent format before the Formatter step runs.

Method 2: Use Zapier Formatter to strip non-numeric characters

Sometimes you receive values like $1,234.50 or EUR 99. In these cases, you can add another Formatter by Zapier step before the math operation to clean the value:

Insert a new step before the step that fails.
Select Formatter by Zapier as the app.
Choose the Text event.
Use a Replace or Extract Number operation (depending on the available options in your account).
Map the original field (for example, $1,234.50) as the input.
Remove characters like currency symbols or commas so the output becomes a plain number (for example, 1234.50).
In your next Formatter or math step, use the cleaned output from this new step instead of the original field.

This method lets Zapier safely convert formatted currency or mixed text into a numeric value.

Method 3: Validate numbers with a Zapier filter

If your workflow sometimes receives invalid data, add a filter in Zapier so only proper numeric values continue:

Insert a Filter by Zapier step before the failing Formatter step.
Set a condition such as “Field” > (Text) Contains > 0–9 or a similar numeric check.
Test the filter with real sample data.
If the data does not match your numeric rule, the Zap will stop before reaching the Formatter step.

Using filters in Zapier prevents unnecessary errors and stops invalid tasks from running further.

Formatting numbers correctly in Zapier Formatter

Different Formatter events in Zapier expect slightly different numeric formats. Keep these points in mind:

Decimals: Use a period as the decimal separator, such as 10.5.
No currency symbols: Remove $, €, £, or other symbols before passing the value.
No commas: Avoid thousand separators like 1,000; use 1000 instead.
No extra spaces: Trim any leading or trailing spaces from the field.

These practices help Zapier interpret the input strictly as a number, which avoids the invalid syntax error.

Testing your Zapier workflow after changes

After you adjust the steps, run tests directly in the Zapier editor:

Open each updated step, starting with the one supplying the number.
Click Test or Test Step to fetch new sample data.
Confirm that the field passed into Formatter by Zapier is a clean numeric value.
Run a full test of the Zap to simulate a complete workflow.
Check the Zap history to verify that the error no longer appears.

If the error persists, carefully compare the input data in a successful run versus a failed run to see what changed.

When to contact Zapier support

If you still see the message “Invalid Syntax: Only numeric values are allowed” after trying the fixes above, you may need extra help from the Zapier support team. Reach out when:

The field clearly contains a normal number, but the Formatter step still fails.
Only some tasks fail, and you cannot identify any input difference.
You suspect a bug or undocumented limitation in Formatter by Zapier.

Collect screenshots of your step setup, the input data, and the full error, then share them with support so they can investigate faster.

Additional Zapier resources

You can review the original help documentation about this Formatter issue directly on the Zapier support site here: Formatter error: Invalid Syntax: Only numeric values are allowed. For broader automation strategy, process design, and integration guidance that complements your Zapier usage, you can also explore expert resources at Consultevo.

By understanding how numeric fields work in Formatter by Zapier and cleaning your data before each operation, you can resolve the “Only numeric values are allowed” error and keep your automations running reliably.

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Fix Formatter numeric errors in Zapier