How to check if a number is on WhatsApp before you send

Check if a number is on WhatsApp: one number

Open wa.me/ followed by the full number in international format, without the plus sign, spaces or leading zeros. If the number has WhatsApp, a chat opens. If not, WhatsApp shows that the number is not on WhatsApp or the link is invalid.

You can also save the number on your phone and look for it in WhatsApp's contact list, but that adds a contact you may not want.

There is no official WhatsApp tool for checking a whole list at once, and services that offer to test thousands of random numbers are mostly used for spam. For your own customer list, the practical approach is the one below: fix the formats, let the import catch invalid numbers, and let the campaign skip the rest.

A typical result for an older list is a noticeable share of skipped rows. That is normal and not a sign that anything is broken; it is exactly the information you need to clean the list, fix typos and decide which customers to reach another way.

The sections below go from checking one number by hand to cleaning an entire list and keeping it clean campaign after campaign.

Keep in mind that a number being on WhatsApp is not the same as the person wanting your message. Checking tells you whether a message can be delivered; consent tells you whether it should be sent. Clean lists need both.

Why bad numbers matter

Every attempt to a number that is not on WhatsApp wastes time in a campaign, and many failures in a row are a signal worth stopping for. Cleaning the list first also gives you an honest picture of how many customers you can actually reach.

Clean the list before you import

Most problems are format problems: missing country code, an extra leading zero, spaces or dashes, or Excel turning the number into scientific notation. Keep the phone column as text and set a default country code for local numbers.

Wassender's import preview flags duplicates, empty cells and invalid numbers, and excludes invalid and duplicate numbers from the campaign before it starts.

Skipping numbers not on WhatsApp while sending

During a campaign Wassender skips numbers that are not on WhatsApp and marks them as skipped in the log and the report. It also pauses automatically after repeated failures, so a bad list does not keep failing unattended.

After the run, export the report to Excel and remove or correct the skipped rows in your source sheet, so the next campaign starts cleaner.

Fixing number formats: before and after

"0501234567" with default country code 966 becomes 966501234567. "+966 50 123 4567" becomes 966501234567 once spaces and the plus sign are ignored. "00966501234567" has an international prefix; remove the leading 00. "9660501234567" has both a country code and the local zero; remove the zero after 966.

"5.01E+08" is Excel's scientific notation and the original digits may already be lost; go back to the source system and export again with the column as text. "050-123-4567 / 055-765-4321" holds two numbers in one cell; split them into two rows with the same name.

Landlines can appear valid in format but rarely have WhatsApp. If your list has a separate landline column, do not select it as the phone column.

Reading the report after a run

Each recipient ends up as delivered, failed, skipped or replied. Skipped means the row was not sent, for example an invalid recipient, a duplicate or a number on the opt-out list. Failed means an attempt did not succeed; read its note before retrying.

A practical routine: after each campaign, export the report to Excel, filter for skipped and failed, and fix or delete those rows in your master customer sheet. Mark numbers confirmed as not on WhatsApp so they do not come back with the next export.

Common mistakes: retrying the same bad numbers every campaign, which keeps failure counts high; deleting a customer instead of fixing an obvious typo; and assuming a skipped customer saw the message. If an important message, such as an order update, was skipped, reach that customer another way, for example by phone.

Keeping your customer list clean over time

Numbers change. People switch carriers, move countries or stop using a phone, and a list that was clean last year slowly fills with numbers that no longer have WhatsApp. Make cleaning part of your routine rather than a big job once a year: after every campaign, spend a few minutes on the skipped and failed rows.

Collect numbers in the right format from the start. On your website or booking form, ask for the country and the mobile number in separate fields, or show an example such as 966501234567. At the counter, read the number back to the customer before saving it. These small steps prevent most of the errors you would otherwise fix later.

Keep one master sheet for customers and treat exports from other systems as updates to it, not as new lists. Add a status column with values such as active, not on WhatsApp and opted out, and filter on it before each import. Combined with Wassender's duplicate and invalid-number checks, this keeps each campaign focused on customers you can actually reach.

Respect the purpose

Checking numbers is for cleaning your own customer list, not for testing random numbers to find new people. Only message people who expect to hear from you.

Step by step

1. Format the phone column as text and fix obvious typos.
2. Import the list into a Wassender campaign and set the default country code.
3. Review the preview for invalid and duplicate numbers.
4. Send with a careful pace; numbers not on WhatsApp are skipped.
5. Export the report and clean the skipped rows in your sheet.

Plan: Every new account gets 1 hour of Unlimited free from its first campaign, no card needed. After that, sending needs a paid plan: US$9.99 a month, US$79 a year or US$99 once for Lifetime. Nothing renews unless you switch on auto-renew for Monthly at checkout, and you can cancel that anytime.

Frequently asked questions

Keep reading

• Message unsaved numbers →
• Delivery reports guide →
• Campaigns guide →