# Bulk Phone Number Formatter: E.164 and CSV | Dedupely > Format a list of phone numbers to E.164, international or national in one pass. Pick a default country, catch invalid numbers and download a clean CSV. Free. - URL: https://dedupe.ly/tools/phone-number-formatter - Section: tools - Site index: https://dedupe.ly/llms.txt - Any page: append `.md` to its URL for this plain-text form --- ## Format phone numbers to E.164 in bulk Paste a column of numbers and get E.164 back with the bad ones flagged. [Use in Claude](https://claude.ai/customize/connectors?modal=add-custom-connector&connectorName=Dedupely%20free%20tools&connectorUrl=https%3A%2F%2Fdedupe.ly%2Ftools%2Fmcp) CSV file Or paste rows here First row is a header Run Free for 10 runs a day. ### One phone number written five ways (415) 555-0199 and +1 415 555 0199 are one line. A CRM compares them as text. The duplicate survives. **This tool rewrites every phone number to E.164 so the copies line up.** ### Add the country code the import left out Local numbers arrive with no country code. A dialer or an SMS step rejects them. Each CRM guesses a different country. **Pick a default country and every local phone number gets its code.** ### Use it from a script or an AI agent [Use in Claude](https://claude.ai/customize/connectors?modal=add-custom-connector&connectorName=Dedupely%20free%20tools&connectorUrl=https%3A%2F%2Fdedupe.ly%2Ftools%2Fmcp) MCP https://dedupe.ly/tools/mcp every free tool in one connector (this one: format_phone_numbers) POST https://dedupe.ly/tools/api/phone-number-formatter { "numbers": ["(415) 555-0199", "020 7946 0958"], "defaultCountry": "US" } Docs https://dedupe.ly/tools/api/openapi.json [OpenAPI document](https://dedupe.ly/tools/api/openapi.json) · [API index](https://dedupe.ly/tools/api) · [llms.txt](https://dedupe.ly/llms.txt) ### Questions about phone number formats What is E.164 format? The international standard for a phone number: a plus sign, the country code and the number, with no spaces and at most 15 digits. +14155550199 is E.164. What is the difference between E.164, international and national format? E.164 is digits only after the plus sign. International format adds spaces: +1 415-555-0199. National format is how the number is dialled at home: (415) 555-0199. Which countries does it know? The length and format rules of 44 countries. A number with a plus sign from any other country still gets its E.164 form. Why is a number marked invalid? Its length does not fit the country, it contains letters, or it is a North American number whose area code or exchange cannot exist. Why are some numbers marked fictional? They are in ranges set aside for films and tests, such as 555-0100 to 555-0199 in North America. A real customer never has one. Why does Excel drop the plus sign or the leading zero? Excel reads the column as a number. Import the CSV with that column set to Text, or open the file in a text editor. What phone format does HubSpot want? A plus sign, the country code and the number, such as +12125550123, with ext and the extension after it. How many numbers can I format? 300 phone numbers a file and ten runs a day, free. ### More free tools [CSV dedupe](https://dedupe.ly/tools/csv-dedupe) [Name splitter](https://dedupe.ly/tools/name-splitter) [Email normalizer](https://dedupe.ly/tools/email-normalizer) [List merger](https://dedupe.ly/tools/list-merger) [Domain extractor](https://dedupe.ly/tools/domain-extractor) [Company normalizer](https://dedupe.ly/tools/company-normalizer) [Test data generator](https://dedupe.ly/tools/test-data-generator) [CRM import checker](https://dedupe.ly/tools/import-checker) [Phone number formatter](https://dedupe.ly/tools/phone-number-formatter) [Job title normalizer](https://dedupe.ly/tools/job-title-normalizer) [Fake contact generator](https://dedupe.ly/tools/fake-contact-generator) [Duplicate cost calculator](https://dedupe.ly/tools/duplicate-cost-calculator) [CSV to Excel](https://dedupe.ly/tools/csv-to-excel) [Excel to CSV](https://dedupe.ly/tools/excel-to-csv) [CSV validator](https://dedupe.ly/tools/csv-validator) [VCF to CSV](https://dedupe.ly/tools/vcf-to-csv) [CSV to VCF](https://dedupe.ly/tools/csv-to-vcf) [CSV to chart](https://dedupe.ly/tools/csv-to-chart) ### Get started for free 20 free trial merges and as much free support as you need to get your duplicates under control. [Talk to sales](https://meetings.dedupe.ly/meetings/hampus-isaksson/dedupely-zoom-schedule)[Try for free](https://v2.app.dedupe.ly/signup) [Or sign up with Google](https://v2.app.dedupe.ly/signup/google) Running CRM cleanup for clients? [See the Partner Program](https://dedupe.ly/become-a-partner) Skip to content