Mobile phone number format in HubSpot

Use E.164 format (recommended)

HubSpot phone numbers should be stored in E.164 format:

• A plus sign +
• Country code
• Full national number (without the leading trunk 0)

Example (UK): +442079460958 Example (UK mobile): +447700900123

Avoid spaces and punctuation if you can. HubSpot will display formatting nicely anyway, but integrations are happiest with plain E.164.

How to confirm the number is valid in HubSpot

When you click into a phone field on a contact record (for example Mobile phone number), HubSpot will show a status under the input.

You want it to show Validated. If it does not:

• Check the number includes + and the correct country code
• Check there is no leading 0 after the country code (for example +4407… is wrong)
• Use HubSpot's Remove number formatting option if you pasted something messy, then re-save

CSV/Excel import tips (so HubSpot doesn't mangle it)

Keep phone numbers as text

Excel loves "helping" by removing the + or converting long numbers into scientific notation.

Before importing:

• Format the phone column as Text (Home → Number format → Text), then paste values
• Or prefix values with an apostrophe in Excel: '+447700900123 (the apostrophe won't import into HubSpot, it just forces text handling)
• In CSV files, wrapping values in quotes is also helpful: "+447700900123"

Excel formula: clean phone numbers to E.164

If you have a spreadsheet full of messy phone numbers in various formats, the formula below will clean them into E.164 format, ready for HubSpot import.

It handles all common input formats including:

• Local numbers with a leading 0 (e.g. 07700 900123)
• Numbers with + and country code (e.g. +44 7700 900123)
• International dialling prefix 00 (e.g. 0044 7700 900123)
• The dreaded +44(0)7... format
• Hyphens, dots, brackets, and other punctuation
• Numbers that already have the country code but no + (e.g. 447700900123)

How to use it

1. Copy the formula below
2. Paste it into any cell in your spreadsheet
3. Change A2 to point to your first phone number cell
4. Change "44" to your country code (see the country reference table below)
5. Change 10 to the expected mobile number length for your country
6. Press Enter, then drag down to apply to all rows

The formula

=LET(
  cell, A2,
  country_code, "44",
  nsn_len, 10,
  raw, TRIM(cell&""),
  clean, SUBSTITUTE(raw,"(0)",""),
  digits, TEXTJOIN("",,IFERROR(MID(clean,SEQUENCE(LEN(clean)),1)*1,"")),
  has_plus, ISNUMBER(FIND("+",raw)),
  has_00, LEFT(digits,2)="00",
  p, LEN(country_code),
  starts_cc, AND(LEFT(digits,p)=country_code, LEN(digits)=p+nsn_len),
  nsn, IF(has_plus, digits,
       IF(has_00, MID(digits,3,999),
       IF(starts_cc, MID(digits,p+1,999),
       IF(LEFT(digits,1)="0", MID(digits,2,999), digits)))),
  intl, IF(has_plus, "+"&digits,
        IF(has_00, "+"&MID(digits,3,999),
        IF(starts_cc, "+"&digits,
        "+"&country_code&nsn))),
  is_domestic, AND(NOT(has_plus), NOT(has_00), NOT(starts_cc)),
  IF(raw="","",
    IF(digits="","REVIEW (not a number): "&raw,
      IF(AND(is_domestic, LEN(nsn)<nsn_len),"REVIEW (number too short): "&raw,
        IF(AND(is_domestic, LEN(nsn)>nsn_len),"REVIEW (number too long): "&raw,
          intl))))
)

What the three config variables mean

• cell — the cell containing the raw phone number (change to match your column, e.g. G2)
• country_code — the default country code to apply to domestic numbers (e.g. "44" for the UK, "1" for the US)
• nsn_len — the expected length of the national subscriber number (mobile). For the UK and US, this is 10. See the country reference table below.

How it works

The formula takes four different paths depending on what it finds in the input:

1. Has + in the original — already international, strip to digits and prepend +
2. Starts with 00 — international dialling prefix, strip the 00 and prepend +
3. Starts with the country code AND digit count matches — bare international (e.g. 447700900123), prepend +
4. Everything else — domestic number, strip leading 0 and prepend + plus the country code

Before any of this, the formula removes (0) from the raw input, so +44(0)7700 900123 is handled cleanly.

What about invalid numbers?

Numbers that don't pass validation return a clear message so you can filter and fix them:

• REVIEW (not a number): hello world — no digits found at all
• REVIEW (number too short): 07700 — not enough digits for a valid number
• REVIEW (number too long): 077009001234 — too many digits, possibly a double prefix

Country code reference

Here are the most common country codes and their mobile NSN lengths for use with the formula:

Quick troubleshooting checklist

If your WhatsApp sends fail:

• Confirm the HubSpot property contains E.164 format
• Confirm the field shows Validated
• Make sure the number includes the country code and no leading 0 after it
• Ensure you're using the correct HubSpot property in your workflow action (the one that actually contains the WhatsApp number)