Deduplication
Find every duplicate. Across the whole CRM. At £0.00.
Different spellings, different formatting, same person. Datuma surfaces every duplicate pair across your full CRM export, with confidence scores, ready for your team to merge or keep.
Deduplication, free on every list
How many duplicates are hiding in your list?
Drop in a CRM export and Datuma counts the exact duplicate records, right here in your browser. Your file never leaves your machine, and nothing is uploaded.
Count your duplicates in seconds.
The in-browser counter needs JavaScript. With it on, you can drop a CRM export here and see your exact duplicate count without uploading anything. Or create a free account to run the full scan, which also finds the likely-duplicate matches under different spellings.
Start freeChoose a CSV export or drag it here
Your file never leaves your browser. Nothing is uploaded.
Counting duplicates in your browser...
In your file
You have at least 0 exact duplicate records
Every duplicate is a record you would pay to enrich twice, and a person who gets mailed or called twice. Datuma collapses them so you only keep the people you actually have.
No exact duplicate records in this file
Nothing matched exactly across 0 rows. That is the easy half. The full scan also finds the likely-duplicate matches under different spellings, which exact matching walks straight past.
We could not find an email or LinkedIn column to match on
This quick count matches on email and LinkedIn. The full scan goes further, matching on names, organisations and more, so it catches duplicates this preview cannot.
We could not read that file
Export your contacts as a CSV and try again. Nothing was uploaded, so you can drop another file straight away.
This quick count finds exact matches only. The full scan also finds likely-duplicate matches under different spellings. Your file never left your browser.
Signing up unlocks the full scan and your cleaned file. Deduplication is always free, at any size. No card to start.
You stay in control
You decide which record wins. We never overwrite without you
This is the review you get in your portal. Datuma finds the duplicates and shows them side by side, with the differences highlighted. You decide. Nothing changes in your CRM until you act on it.
The removed record appears in your CRM Actions file as a merge or delete recommendation.
The removed record appears in your CRM Actions file as a merge or delete recommendation.
Deduplication and review are always free. Your first 100 contacts are free too.
The 1× / 10× / 100× rule of bad data
SiriusDecisions (now part of Forrester) popularised a long-standing data-quality benchmark, the 1-10-100 rule. Costs scale by an order of magnitude at each stage:
to verify a record as it enters the CRM
to clean it up after it's already in the CRM
if it's left untreated and acted on by sales, marketing, or finance
Duplicates are the single biggest source of that 100× cost. The same contact in three records means three sequences, three calls, three sales reps thinking they own the relationship. Pipeline gets inflated. Forecasts get fabricated. And the customer gets contacted by people who don't know about each other.
What that looks like in your CRM
Set two numbers and watch the rule play out. Nobody knows their real duplicate rate until they scan, so pick your best guess. Most teams guess low.
That would be roughly
250 hidden duplicate records
Caught at upload. Datuma's full-database scan surfaces every pair before anyone acts on them, with the evidence and a confidence score. Deduplication costs nothing, at any size, and your team decides what merges.
Cleaned up by hand. Someone finds each pair, works out which record is real, and merges it without losing the history. Assumes 10 minutes per pair at £30 per hour of staff time. It rarely happens, because nobody volunteers for it.
- ✉Up to 250 duplicate emails per campaign. The same person, mailed twice, every send.
- ☎Two reps, one prospect. Both think they own the relationship. The prospect gets two cold calls in the same week and remembers your brand for the wrong reason.
- ⚠Spam complaints compound. Gmail blocks bulk senders whose complaint rate passes 0.3% (Google Email Sender Guidelines, 2024). Double-mailing the same inboxes is how you get there.
- ▦Inflated pipeline. Duplicate records double-count deals, so the forecast is wrong before anyone touches it.
- ●And the customer notices. "Didn't I already tell you this?" is how trust ends.
Estimates, not bills. Based on 5,000 contacts at a 5% duplicate rate, 10 minutes and £30 per hour to fix one embedded pair by hand. The 1×/10×/100× rule: SiriusDecisions (now Forrester). Your real duplicate rate takes about five minutes to find, free.
Why your CRM's dedup tool misses them
Different spellings
"Alasdair Carter", "Ali Carter", "A. Carter". Same person, three records. Exact-match dedup catches none of these.
Different formatting
One record has the email in lowercase, one has trailing whitespace, one has the organisation as "Acme Ltd" vs "Acme Limited". Off-the-shelf dedup walks past these.
Role or organisation changes
Same person, different organisation, different email domain, no fuzzy match on first/last name alone. Without identity-aware matching, they live as two unrelated contacts forever.
Per-import scans only
Most CRMs dedup within an import. They don't run a full pairwise scan across the entire database. So your 50,000-row CRM has thousands of hidden duplicates that have been sitting there for years.
How Datuma finds them all
Full-database scan, not per-import
Export your CRM. Upload once. Datuma runs a complete pairwise scan across every contact in the file. Every duplicate pair, no matter how old, no matter when it was added.
Fuzzy matching with confidence scores
Different spellings, casing, whitespace, and abbreviation differences are all matched. Each pair comes back with a confidence score and the matching evidence, so your team can review the ambiguous ones and trust the clear ones.
Within-batch and cross-batch
New batches are deduplicated within themselves and against every prior batch you've ever uploaded. No more "we already enriched this person three months ago" surprises.
Your team decides: merge or keep
Datuma never auto-merges. Each pair is presented in a review page with the matching evidence. Your team picks merge or keep separate. Decisions are remembered for next time.
Dedup is always £0.00
Deduplication runs before you pay to enrich anything. The full-database scan is £0.00. You only pay for fresh enrichment on contacts that aren't already in your system.
Common deduplication jobs
Find duplicate contacts across two lists
Upload both lists. Datuma checks each new batch against itself and against every list you have ever uploaded, so the same person appearing in two lists, or in a list and an earlier CRM export, is surfaced automatically. Each pair comes back with the matching evidence and a confidence score, and your team decides what merges. Cross-list matching is where an in-CRM dedup tool, which only looks within a single import, walks straight past the duplicate.
Remove duplicates from a spreadsheet before import
Clean the file before it ever reaches your CRM. Export or assemble your list, run it through Datuma, review the duplicate pairs, and import only what you want to keep. Catching duplicates before import is the cheapest place to catch them, and it stops two records for the same person being created in the first place. The full duplicate scan is £0.00, at any size.
Which contacts can you trust
Deduplication tells you which records are copies. A Trust Score from 0 to 100 tells you which records are worth acting on. Every contact is checked live and scored, so once the duplicates are merged you can sort the survivors by how much of the data holds up. See the AI Blockers that hold a contact back, or how every contact is scored.
Deduplication, common questions
How do I find duplicate contacts across two lists?
How much does deduplication cost?
Why does my CRM miss duplicate contacts?
Does Datuma merge duplicates automatically?
See your duplicate rate in five minutes
Upload a CRM export. Datuma surfaces every duplicate pair with confidence scores. Free to find them. Your team decides what to do.