Every lead source you pay for will claim credit for the same closing. The portal says the buyer first inquired there. The Facebook campaign says she clicked an ad. Your sphere says she was a friend of a friend. At the end of the month you have a commission statement, a handful of subscriptions, and no honest way to say which one earned its place. That gap, not a shortage of options, is why this question is so hard to answer from the outside.
Score each source by closings, not inquiries
Inquiries are the cheapest thing to count and the least useful. A source that sends many forms and no signed agreements is expensive, however low the price per lead looks. Track every source through the same stages: inquiry, conversation, appointment, signed agreement, closing. Then divide what you spent by the closings that came out the other end. That figure is the only fair basis for comparing a portal, a referral network, paid search, social ads and your own past clients.
| Source type | What it tends to be good at | What to check before you rely on it |
|---|---|---|
| Past clients and sphere | Trust and repeat business at little cash cost | Whether you contact them on a schedule or only when you remember |
| Paid portals and lead marketplaces | Fast volume of active buyers | Whether leads are shared with other agents and how quickly you respond |
| Paid search | Reaching people who are searching right now | Cost per click against how many clicks become signed agreements |
| Paid social | Local awareness and seller-side interest | Lead quality once someone answers the phone |
| Open houses and signage | Face-to-face relationships in one area | Whether you record every visitor's contact details and follow up |
Tag the source before the lead reaches your phone
Most attribution problems begin at the moment of entry. A lead arrives by phone, text or form, and the source is guessed later from memory. Give each source its own tracking phone number or form field, and put a required source dropdown in your CRM for anything entered by hand. If you run ads, make sure form submissions and calls are recorded as conversions in your ad and analytics accounts, so they can be matched to campaigns instead of left as unexplained traffic.
How much search interest is behind this question
Across five closely related phrasings, searches for the best lead source for realtors add up to roughly 130 a month. That is a small, specific audience, mostly agents and brokers weighing where to put money. Interest also moves through the year. The last twelve months peaked at 110 a month in January 2026 and dipped to 50 a month in August 2026. The January peak fits the habit of reviewing plans and budgets at the start of a year. It suggests many agents ask this question once, in a planning mood, rather than continuously.
Paid clicks in this market are not cheap
Advertisers competing for the top of the page on realtor-related searches have paid as much as $64.10 for a single click at the high end. That is a ceiling, not an average, and your own cost will usually be lower. It still tells you that a lot of agents and lead companies are bidding for the same searchers. A campaign that isn't tied to closings can burn through a monthly budget quickly. Any paid test needs a clear stopping rule and a counted outcome, or it turns into another subscription you never review.
A test you can afford to finish
Pick at most two sources to compare, and hold everything else steady. Set a spending cap you could lose without stress. Decide in advance what counts as a win, such as a signed agreement or a booked listing appointment. Answer every lead within the same short window for both sources, so speed doesn't skew the result. Let the test run long enough for leads to move through your normal sales cycle. Real estate closes slowly, so early results mostly show lead quality, not final returns.
When the test ends, keep what produced closings at a cost you can defend, pause what didn't, and note why. The answer may be a portal for one price band, past-client outreach for another, and nothing paid for a third. The best source is the one that works for your market, your price range and your follow-up habits, not the one that tops a generic ranking.
Getting a second set of eyes on the numbers
You can do all of this alone with a spreadsheet and some discipline. Outside help makes sense in a few situations. Your ad accounts and analytics don't agree on where leads came from. Calls are converting but nothing is being recorded. Or you're spending enough on paid search that a tracking mistake costs real money. An agency that works in paid advertising and analytics can audit how conversions are recorded, tell you which numbers you can trust, and then leave you to make the budget decision. If your records already tie sources to closings, you may not need anyone.