Quick Answer: Cancel ADT by calling 800-238-2727 — there’s no online or app cancellation option. If you’re still inside your 36-month contract (24 months in California), expect an early termination fee of up to 75% of your remaining monthly charges, according to SafeWise’s and Alarm Relay’s ADT cancellation guides. You can avoid the fee entirely by canceling within 72 hours of signing, by waiting until your contract term ends and rolls to month-to-month, or by qualifying under ADT’s 6-month technical-issue service guarantee. Outside those cases, ADT mails a prepaid box to return financed equipment — a real difference from no-contract brands where you keep the hardware regardless.

Last updated September 19, 2026.

ADT’s monitoring is genuinely strong — trained agents watching for triggered alarms, ready to dispatch police or fire — but that service comes wrapped in the home-security industry’s most notorious cancellation friction: a multi-year contract, a phone-only exit, and a termination fee that can run into four figures. Here’s the actual process and the exact math behind the fee.

How to cancel ADT, step by step

StepWhat to do
1. Call 800-238-2727ADT's only cancellation channel — no online form or app toggle exists for Pro Install accounts
2. Have your info readyAccount number, service address, and the name the contract is under
3. Ask for the exact ETFRequest the agent calculate your current early termination fee before you agree to anything
4. Expect a retention offerADT's retention team commonly offers a discounted rate or reduced fee to keep the account — you can decline and still proceed with canceling
5. Confirm the effective dateGet written confirmation (email) of the cancellation date and any final balance owed
6. Return financed equipment if askedADT will mail a prepaid box with return instructions if your contract wasn't already fulfilled

The early termination fee, in real numbers

The ETF formula

(months remaining) × (monthly rate) × 0.75 — per SafeWise's and Alarm Relay's ADT cancellation research
  • 6 months left on a $45.99/month plan ≈ $207
  • 12 months left on a $59.99/month plan ≈ $540
  • 24 months left on a $64.99/month plan ≈ $1,170
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The three ways to skip the fee entirely: cancel inside the 72-hour buyer’s-remorse window right after signing (equipment gets picked back up, you don’t keep it), let your 36-month term run out and roll onto ADT’s fee-free month-to-month, or invoke ADT’s 6-month service guarantee if a genuine technical issue with the system was never resolved. That last one isn’t a general dissatisfaction clause — it’s specifically for unresolved equipment or monitoring malfunctions, so a simple “I want to pay less” doesn’t qualify.

Why ADT’s exit looks so different from Ring, Arlo, or SimpliSafe

BrandCancel channelContractEquipment after canceling
ADTPhone only (800-238-2727)36 months typical (24 in CA)Return financed hardware unless term fulfilled
RingApp or websiteNoneKeep it — hardware is owned outright
Arlomy.arlo.com or appNoneKeep it — cloud recordings deleted within 48 hours
SimpliSafePhone or chat (state-dependent online option)None, month-to-monthKeep it — runs locally, unmonitored

ADT’s model finances or discounts the hardware against a signed monitoring term, which is exactly why the exit costs money and the gear sometimes has to go back — see our how to cancel a Ring subscription, how to cancel an Arlo subscription, and how to cancel a SimpliSafe subscription guides for how much simpler that process is once there’s no financed equipment or long-term contract involved. If the contract itself is the dealbreaker, our ADT vs Ring comparison and best DIY home security system guide both cover no-contract alternatives that still include professional monitoring as an optional add-on, not a locked-in term.

The bottom line

Calling 800-238-2727 is the only way to cancel ADT — budget time for a retention pitch, and ask the agent to calculate your exact early termination fee (up to 75% of what’s left on your 36-month term) before agreeing to anything. Canceling inside 72 hours of signing, waiting out the full term, or qualifying under the 6-month technical-issue guarantee are the only ways to skip that fee entirely. Once you’re free of the contract, our best DIY home security system guide and ADT vs Ring comparison both cover no-contract systems that still offer professional monitoring as an option instead of a requirement.