Clean customer data before importing it into a CRM
A customer list built up over months or years — from forms, spreadsheets, other systems — carries every inconsistency each of those sources introduced. Importing it into a CRM as-is means duplicate contacts, broken filters, and mail merges that put "JOHN SMITH" in a greeting. DataMadeClean cleans the whole list in one pass before it goes anywhere near your CRM.
No account needed · CSV and XLSX · works with any CRM's import format
What a customer list looks like before it's cleaned
None of these problems are unusual on their own — a customer list just tends to have several of them at once.
- The same customer entered more than once, with slightly different capitalization or spacing each time
- Names in inconsistent case — "john smith", "JOHN SMITH", "John Smith" — that will show up exactly as typed in every email and report
- Phone numbers formatted differently depending on who entered them
- Signup or last-contact dates in more than one format, breaking anything that sorts or filters by date
- Blank or missing fields where a CRM import expects a value
Before / after
The same list, ready to import
Before
| Name | Phone | Signup | |
|---|---|---|---|
| JOHN SMITH | JOHN@EXAMPLE.COM | 0412-345-678 | 13/04/2026 |
| John Smith | john@example.com | +61 412 345 678 | 2026-04-13 |
| Priya Nair | priya@lumen.co | 0430987654 | 2026-04-05 |
After
| Name | Phone | Signup | |
|---|---|---|---|
| John Smith | john@example.com | 0412 345 678 | 2026-04-13 |
| duplicate — removed | |||
| Priya Nair | priya@lumen.co | 0430 987 654 | 2026-04-05 |
Illustrative output with ISO date format and Australian national phone format selected. Matching rows are removed after cleaning. Check your CRM field requirements and review the results before import.
What gets cleaned
Every field a CRM import cares about
How DataMadeClean handles it
Upload, review, download
Upload your list
Export it from wherever it currently lives — CSV or XLSX, no account needed to try it.
Automatic detection
Name, email, phone and date columns are identified automatically.
Clean in one pass
Duplicate rows are removed, casing and whitespace normalized, and phone numbers and dates standardized together.
Review & download
See exactly what changed, then download a file ready to import into your CRM.
Your file is only ever used to clean it. An anonymous upload and its result are deleted an hour after cleaning; signed in, results follow your account's retention setting.
About to import a contact list into your CRM?
Clean it first, free →Questions about cleaning customer data
What does it clean in a customer list?
Names are made consistent in casing, email addresses are trimmed and lowercased, phone numbers and dates are brought to one format per column, and duplicate rows are removed — in a single pass, in an order where normalizing happens before matching. Every change is listed individually, so nothing is altered without you being able to see exactly what it was and what it became.
Will it merge duplicate customers?
Rows matching across every column after cleaning are removed, keeping the first occurrence. Fields from separate rows are not combined. Pro checks can flag similar names sharing an email address or phone number for review. They do not automatically merge contacts or delete near-matching rows. Exact duplicate row removal is included on every plan.
Does it check that addresses are real?
For Australian data, yes, as a Pro feature: suburb, state and postcode combinations are checked against G-NAF, the official national address file, so a mismatch like Brisbane paired with NSW is flagged rather than tidied up and passed through. Outside Australia, postcodes are checked for the right format for the region rather than against an address database.
Will it change my email addresses?
Surrounding spaces are removed and casing is standardized, which makes addresses that differ only in casing match; check any systems that distinguish mailbox casing. A likely misspelling of a common domain, such as gmial.com, is flagged with a suggested correction rather than rewritten on a guess. It does not check whether a mailbox exists.
How long is my file kept?
Anonymous uploads and their results are deleted an hour after cleaning. Signed in, results follow your account's retention period, seven days by default, and you can shorten it or delete a result yourself at any time. Read the privacy policy.
Can I apply the same rules to every export?
Yes. Saving your choices as a recipe lets the next file of the same shape be cleaned the same way, which is what makes this usable for a CRM import you run every month rather than once.
Upload your customer list and see it ready to import.
No signup required.
Clean a file free →Get in touch if you have a question first.