Free Diagnostic Tool

Could Your Zestimate Be Wrong?

If it is, it could be costing you tens of thousands of dollars — and you'd never know. We'll audit your Zestimate for feedback loops, data errors, and algorithmic penalties. If it's suppressing your home's value, we'll help you zillowmaxx it.

Built from a real investigation that uncovered a $220,000 Zestimate error on a single home — confirmed by Zillow support. See anonymized sample audits.

Find yours at zillow.com → search your address → copy the Zestimate® number

Zillow won't let us check your Zestimate history 🙄 but you can: go to zillow.com → your home → click 'Zestimate history' → switch to table view → select all → paste here

Pick a similar home nearby. Same street is ideal.

Enter what Zillow shows for your home. We'll check it against Redfin.

The quick audit works great. These inputs unlock additional diagnostic signals for an even more detailed analysis.

Z
zillowmaxxing
/zil·oh·maks·ing/ verb, present participle

The act of systematically eliminating every data error, algorithmic penalty, and feedback loop suppressing your home's Zillow estimate — by correcting every datapoint, visual cue, and comp disadvantage dragging your property below its true market tier.

"She corrected the square footage, uploaded 20 interior photos, fixed the missing bedroom, filed a support ticket on the phantom sale — and her Zestimate jumped $95K in two weeks. Full zillowmaxxing."

What the Free Audit Can Find

A clear diagnosis, backed by receipts.

The free audit does not sort homes into three vague buckets. It makes one of five plain-English calls, then shows which evidence families supported that call.

Outcome

Aligned

Zillow broadly agrees with the readable independent data.

Outcome

Needs More Evidence

There are clues, but not enough directional evidence to make a strong call.

Outcome

Suppression Signs

Some evidence points toward Zillow running low, but the chain is not complete.

Outcome

Doom Looped

Multiple signals suggest stale or suppressed data may be reinforcing itself.

Outcome

Overvaluation Signs

Independent sources suggest Zillow may be running high instead of low.

Evidence the free audit checks

These are not diagnosis categories. They are the inputs we use to decide whether the Zestimate looks aligned, thin, suppressed, doom-looped, or inflated.

AVM gaps Property facts Sale anchoring Zestimate history Neighbor gaps Tax / assessment context

Sample premium outputs

See what the full audit actually looks like.

These are anonymized, frozen audit examples from the test library. They show both sides of the product: sometimes the data tells a strong suppression story, and sometimes it says “slow down, this is only context.”

Premium term

ClearComp™

The hyperlocal comp view. We start with comparable sales from the premium comp source, then show what changes when comps outside the subject municipality are removed.

Premium term

CEDC

Compounded Exponential Discrepancy Chain: our read on whether stale facts, sale anchoring, valuation gaps, and history signals are reinforcing each other.

Anonymized northern NJ sample

Strong suppression story

Same-municipality comps were dramatically higher than the full comp pool, the neighbor gap was large, and sale anchoring made the feedback-loop narrative coherent.

Zestimate$654.9K
CEDCMedium

Anonymized border-town sample

Useful context, not a dramatic call

ClearComp found cross-municipality comp drag, but the public AVM stack stayed close to Zillow. The audit kept the diagnosis conservative instead of forcing a doom-loop story.

Zestimate$367.4K
CEDCLow
View the anonymized case library →

Zillow, in their own words

"The Zestimate relies heavily on recent transaction data. When a home sells, the algorithm anchors to that final sale price. If that sale price was indeed suppressed — whether by an older Zestimate, a lack of historical data, or other factors — the current Zestimate will reflect and reinforce that price point. It is a feedback loop."

— Zillow Support Agent, May 2026

How It Works

1

Enter your address and Zestimate

We need the address to pull public records. You provide your Zestimate because Zillow won't let anyone check it automatically — not even us.

2

We look for the patterns that cost homeowners money

Feedback loops where low estimates cause low sales. Data errors where Zillow has the wrong facts about your home. Algorithm drops from model updates you were never told about. Cross-platform divergences that reveal when only Zillow sees a problem.

3

Get your diagnosis — and your Zillowmaxxing playbook

We tell you if your Zestimate is accurate, suppressed, or inflated. If it's hurting you, you get a personalized playbook of exactly what to fix, where to fix it, and how much it typically moves the needle. That's Zillowmaxxing.

Find out in 30 seconds.

Free. No account. No email. Just the truth about your Zestimate.

Find yours at zillow.com → search your address → copy the Zestimate® number

Questions, feedback, or a good Zillow story?

Send a note directly.

Have a question, a correction, or a Zestimate mystery worth sharing? Send it here. Your email is used only for a reply.

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Preview Mode — Redfin, tax, and sale numbers are simulated. Your Zestimate, neighbor comparison, and history analysis use real inputs. Deploy to Vercel with an Exa API key for fully live results.

✓ Paid records checked ✓ ClearComp™ comp table ✓ CEDC chain check ✓ Zestimate history included ✓ Neighbor comparison included

Diagnostic Confidence: (% — )

The Numbers

Zillow Zestimate

Entered by you from Zillow

Last Sale Price

Tax Assessment

Visual Comparison

Zillow
Last Sale
Tax Assessed
FULL AUDIT

Want the complete picture?

🧾
Paid Property Records

Structured facts, sale history, tax context, and property details when available

📊
ClearComp™ Analysis

Comparable rows cleaned by municipality to detect cross-market comp bleed

🎯
Consensus Score

Statistical agreement across all sources — how much do the models agree?

📋
CEDC Chain Check

Flags whether stale facts, sale anchors, history, and valuation gaps are reinforcing each other

One-time payment. Instant results. Powered by premium records and comparable-sales data.

Valuation Consensus

Median Independent Estimate

Agreement Score

How closely all sources agree

Median vs. Zillow

Spread (Low to High)

Range across all models

CEDC Pattern Check

Are the discrepancies compounding?

CEDC looks for a chain: stale facts, public-record drag, AVM gaps, sale-price anchoring, and Zestimate history reinforcing each other. One weird fact is a clue; a chain is the story.

Premium Valuations

ClearComp™ Report

The hyperlocal comp view that reflects how people actually buy homes.

Total Comps
Same Municipality
Excluded Markets

All Comps Average

Address City Price Dist. Age Match

If a simple API pulls comps from the wrong city, Zillow's neural network might be doing the same thing — but you'd never know, because they don't show you which comps they use.

Gap Analysis

Diagnostic Signals

Each signal is scored independently. More signals = higher confidence.

What This Means

Diagnosis Key

Aligned: available estimates are broadly in range with Zillow. Useful, not an appraisal.
Needs More Evidence: context signals exist, but they do not yet prove Zillow is low or high.
Suppression Signs: at least one valuation signal points low, with supporting context.
Doom Looped: multiple signal families suggest a low Zestimate may be reinforcing itself through history, sale, or comp data.
Overvaluation Signs: Zillow appears high relative to the independent support we found.

The Transparency Problem

We pulled data from every source that allows transparent access. The one number we couldn't verify independently? Your Zestimate. Because Zillow blocks all automated access to your data. Think about what that means.

What You Can Do

Already paid

Add context without buying again.

If you find a Zestimate history table, a close neighbor, or corrected Zillow facts after the full audit runs, add them here and update this premium report using the same checkout session.

No new Stripe checkout. This reruns the paid data pull for the same address so the report can include your added context.

Run Another Audit

Check a neighbor's home, a home you're buying, or re-run this one after making changes.

Want to add context?

Send us what you noticed.

Every home has local quirks the audit may not fully see yet. If there’s useful context behind your result, send a note and we’ll read it.

Sent — thanks. We’ll read it.