Quick answer: an ignition interlock runs $60–$120/mo for the lease (most invoices land near $80–$90), plus $70–$150 install, $20–$30 calibration visits every 30–60 days, and $50–$100 removal. A typical 6-month first-offense program totals $610–$1,010 (mid-range $760); a 12-month term runs $1,045–$1,820.

Provider & Program

Calibration & Extra Fees

Total Program Cost
Effective Monthly Cost
Cost per Day
Lease Total
Calibrations
Install + Removal
Calibration Visits
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What the Major Providers Charge (2025)

ProviderInstallMonthly LeaseNotes
Intoxalock$70 – $150$78 – $120Advertises "as low as $1.96/day"; real invoices cluster at $2.60–$4.00/day
Smart Startfrom $150$60 – $85Warranty included; transfer fee ~$200 reported
LifeSafer$50 – $150$50 – $120Wide state-by-state spread
Draeger$0 – $100~$80Install often bundled into lease; removal ~$55
Guardian$70 – $170$50 – $90Strong in states with certified-provider lists

Advertised ranges collected from provider pricing pages in 2025. Nearly every provider is franchised or state-certified, so your local service center's quote is the only one that counts — and states set some fees directly.

Total Cost by Program Length

TermLow (60/mo lease)Mid (85/mo lease)High (120/mo lease)
6 months$610$760$1,010
12 months$1,045$1,345$1,820
24 months$1,915$2,515$3,440

Low/mid include $100 install + calibrations at $25 every 60 days + $75 removal; high includes $120/mo lease, $30 calibrations, and $100 removal. Your state's term — not the device — is the biggest cost driver.

Typical First-Offense IID Terms by State

StateFirst-offense term (commonly reported)
California6 months
Florida6 months minimum (12+ at 0.15% BAC)
New York6 months minimum (12+ for aggravated DWI)
Texas180 days
Colorado8 months
Arizona12 months
Pennsylvania12 months
Washington12 months

Terms shift with legislation, apply to different offense tiers, and judges can extend them. Treat this table as orientation and verify your term with your DMV, court, or monitoring authority — that's the number the whole budget hangs on.

How the Interlock Cost Calculator Works

An IID program is a lease with fixed bookends. You pay to install, you pay every month for the device and its monitoring, you pay for periodic calibration visits where the device gets downloaded and verified, and you pay to remove it when the term ends. Providers advertise the monthly number; the honest budget is all four pieces.

The formula

Total = install + months × monthly lease + ceil(months × 30 ÷ calibration interval) × calibration fee + removal + misc. Effective monthly = total ÷ months. The state quick-fill just preloads the months field — change it freely if your court paperwork says something different.

How to use it

Pick your provider preset to load typical install and lease figures, then replace them with your actual quote — local service centers vary. Set the term from your court order, and check the calibration interval: some states require 30-day service visits, which quietly adds $10-$15 a month versus the 60-day default. If you've had a lockout or need the device moved between vehicles, add it under misc.

A worked example

A first offense in California, 6-month term, mid-range provider: $100 install + 6 × $85 lease ($510) + 3 calibration visits at $25 ($75) + $75 removal = $760. Effective cost: $126.67 a month, or $4.17 a day — notice how far that sits above the "$2.75 a day" headline rate, because the bookends and service visits amortize into a short term.

Same provider over Arizona's 12-month term: $100 + $1,020 + 6 × $25 + $75 = $1,345, an effective $112.08 a month. Longer terms amortize the fixed fees, which is the one financial upside of a longer requirement — and a reason a violation that extends your term hurts twice.

Frequently Asked Questions

How much does an ignition interlock cost per month?

Expect $60-$120 per month for the lease, with most drivers landing near $80-$90. Advertised teaser rates as low as $1.96/day exist, but real-world invoices cluster at $2.60-$4.00 per day once state-mandated monitoring and service fees are included. Add a $70-$150 installation, $20-$30 calibration visits every 30-60 days, and a $50-$100 removal at the end.

What is the total cost of an interlock for 6 months?

Roughly $610-$1,010, with a mid-range scenario around $760: $100 install + 6 months at $85 + three calibrations at $25 + $75 removal. That works out to an effective $126.67 per month — noticeably more than the advertised lease rate, which is why you should budget on the program total, not the monthly teaser.

Who pays for the ignition interlock device?

Almost always you, the driver. The device, installation, monitoring, and removal are offender-paid costs in every state that mandates IIDs. Some states offer fee reductions or waivers for verified low-income participants — ask the court or monitoring authority, because the discount programs are rarely advertised by the providers themselves.

Can I switch ignition interlock providers mid-program?

Usually yes, but it costs you: a $50-$100 removal from the old provider, a fresh installation fee at the new one, and in some states advance approval from your monitoring authority. Switching only makes sense if your current provider's service is genuinely broken or it stops supporting your area — the price differences between major providers rarely cover two fees.

What happens if I miss an interlock calibration appointment?

Your device goes into a lockout or service-instrument countdown that can disable the car, and you'll pay a service visit fee on top of the missed calibration. Missed or skipped service appointments can also be reported to your monitoring authority as a violation, which in some states extends the requirement. If you can't make a scheduled visit, call the service center and reschedule before the deadline.

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