How to add verified emails to a spreadsheet of leads you already have

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A spreadsheet of leads with no emails is a list you can't use yet. Maybe it came from a trade show badge scan, a referral list someone handed you verbally, or a scrape of company names from an industry directory. Whatever the source, the next step is always the same: turning a name or a company into a working, verified email address.

Doing this one contact at a time by hand is slow and error-prone; guessing at an email pattern and sending to it blind risks bounces that can hurt your sender reputation. This is exactly the job a data enrichment tool is built for, and the real decision isn't whether to use one, it's whether your specific list is big enough, and recurring enough, to be worth the setup. Why guessed addresses bounce, and how to screen them first, is covered in why cold emails bounce.

The options, from least to most effort

• Manual search on LinkedIn Sales Navigator. Good for confirming you have the right person's current name and title, but it doesn't return an email at all; you're still guessing afterward.
• Hunter.io. A simple, purpose-built email finder. Less phone-number data than a full enrichment platform, but a reasonable, focused choice if email is genuinely all you need.
• Apollo.io. A cheaper combined database-and-enrichment tool with built-in sequences too; data quality varies by niche and region, so spot-check a sample before trusting a large batch.
• Amplemarket's enrichment. Amplemarket is a B2B contact database and outreach platform, and its enrichment feature matches your uploaded list against that database, filling in verified emails and phone numbers, and checking whether existing emails you already have still work.

Option	Email	Phone	Verifies existing contacts	Best for
Manual Sales Navigator search	No	No	No	Confirming a name and title only
Hunter.io	Yes	Limited	Partial	Email-only enrichment, simple jobs
Apollo.io	Yes	Yes	Partial	Combined database and enrichment on a budget
Amplemarket	Yes	Yes	Yes	Bulk spreadsheet enrichment plus ongoing verification

How Amplemarket fits this job

Amplemarket's data enrichment takes your existing list (company names, people's names, or partial contact records) and fills in verified emails and phone numbers, plus checks that existing email addresses on your list actually work, rather than assuming a saved address is still valid. This matters more than it sounds: a list you built six months ago has some real share of stale contacts, people who've changed jobs or companies that have changed domains.

Credits are the unit that matters here, not a flat per-contact price: the Startup plan includes 13,500 email credits and 600 phone credits per user, per year. For most small teams enriching lists in the hundreds rather than tens of thousands, that's a generous annual allowance; the phone credit number is the one to watch, since it's noticeably smaller than the email allowance and easier to run through if you're trying to enrich phone numbers for a large list in one go.

Step by step: enriching a spreadsheet you already have

1. Clean your spreadsheet first. Remove obvious duplicates and standardize company names before uploading, since a messy input list wastes enrichment credits matching the same company multiple times under slightly different spellings.
2. Upload the list and map your columns. The tool needs to know which column is the company name, which is the person's name (if you have one), and which is any existing email you want verified rather than replaced.
3. Run a small batch first. Before enriching your whole list, run 20 to 30 rows and check the match quality against companies you already know well. This catches a bad column mapping before it burns through your annual credit allowance on a mistake.
4. Review the match confidence, not just whether a field got filled. A filled-in email with low confidence is worth a second check before you send anything important to it.
5. Export and sync to wherever you actually work, your CRM or your outreach tool, rather than leaving the enriched list sitting in the dashboard.
6. Note which rows didn't match, and decide what to do with them separately. An enrichment run against 400 rows rarely returns 400 matches. The unmatched rows aren't necessarily bad data, they're often smaller companies or less common name spellings the database simply doesn't have yet, and they're worth a short manual pass rather than being silently dropped from your list.

A worked example: is your list actually worth enriching?

Say you have a spreadsheet of 400 leads from a trade show, mostly company names with a few partial contacts. Running that through enrichment at, say, an 80% match rate (realistic for a reasonably well-known industry) gets you roughly 320 usable contacts for a fraction of your annual credit allowance on the Startup plan. If you'd tried to find those 320 emails manually, at even a conservative 5 minutes per contact, that's over 26 hours of work, more than three full working days, for a list that enrichment handles in minutes. This is the clearest version of where a paid tool earns its cost: not because manual research is impossible, but because the hourly cost of doing it by hand outpaces a modest, already-paid-for credit allowance almost immediately at this kind of volume. If the list does not exist yet, see whether Claude can build a lead list.

Where that math doesn't hold: if your list is 15 contacts, not 400, the setup time of mapping columns and reviewing match quality in a new tool can genuinely take longer than just looking up 15 emails by hand.

A second scenario: enriching an old CRM export instead of a fresh list

The trade-show example above is a fresh, one-time list. A different and more common case is pulling an export from a CRM that's a few years old, hundreds or thousands of contacts collected over time, many with no email at all or an email that's since gone stale. This is a worse starting point than a fresh list in one specific way: a chunk of those "existing" emails will quietly fail if you just send to them, rather than bouncing immediately, because some domains accept mail and silently drop it rather than returning a hard bounce. Run the whole export through verification before you run a new campaign against it, even the rows that already have an email filled in, not just the blank ones. Treat this as two separate jobs: filling gaps (true enrichment) and checking what you already have (verification), since a tool that does both in one pass, which Amplemarket's does, saves a second upload round-trip compared to a tool that only does one. If stale contacts are the bigger problem, cleaning up old contacts and job titles deals with that separately.

A practical gotcha worth knowing before you run a large historical export through this: match rates on older data are noticeably lower than on a fresh list, since people change jobs and companies change domains, so budget for a lower return (closer to 50 to 60% usable matches on a genuinely old list, rather than the 80% you'd expect on fresh trade-show contacts) and don't be surprised when a meaningful chunk simply can't be matched at all.

A common mistake worth naming

The most common mistake I see is uploading a list with inconsistent company name formatting, "Acme Inc," "Acme Incorporated" and "Acme" treated as three different companies, and then being surprised the match rate looks worse than expected. Clean and standardize company names before you upload, not after you see a disappointing result. The second mistake is spending a phone credit allowance (600 a year on Startup) enriching phone numbers for a list you're only ever going to email. Map your fields deliberately rather than accepting every available enrichment field by default, since credits used on data you won't use are credits you can't get back until the next annual cycle.

What I'd actually tell you

If you're staring at a spreadsheet with no emails right now, my honest read is that the decision isn't really about which tool to pick, it's about whether this is a one-time problem or a recurring one. A one-time trade-show list of 400 names is worth running through enrichment once, using whatever headroom you already have on an existing plan or a short trial, not a reason to commit to annual billing on its own. A recurring need, a new list every month from a consistent source, is where the subscription actually earns its keep, because you're paying once for a credit allowance you'll draw down steadily rather than in one burst. Once the emails are filled in, following up on cold emails without doing it by hand is the next step.

Where I'd push back on the sales pitch: enrichment vendors tend to emphasize match rate as the headline number, and match rate alone is a weak signal. A 90% match rate on bad, duplicate-heavy input data is worse than an 80% match rate on a clean list, because the first number is partly measuring how many ways it found to match the same company twice. Clean your input first; the match rate you see afterward is the one that actually tells you something.

When to skip the tool, and when it's worth a custom build

Skip a dedicated enrichment tool if your list is under 100 leads, a manual look-up per contact is genuinely faster to set up than onboarding a new subscription. Also watch your phone credits specifically if you're enriching phone numbers at any real volume, since that allowance (600 a year on Startup) runs out faster than the email allowance does.

Where it's worth building on: if your lead lists come in continuously, say from a form, an event platform or a recurring data pull, rather than as one-off spreadsheets, it's worth connecting Amplemarket's enrichment directly to that source through the API so new leads get enriched automatically as they arrive, instead of exporting and re-uploading a spreadsheet by hand each time. I build this kind of automated enrichment pipeline for clients with a steady, recurring lead flow.