How much Guardian Interlock costs
An interlock is never one price. You pay to have it fitted, you pay every month it stays in the car, and you pay to have it taken out — and the monthly fee is where the real money is.
We have not yet confirmed Guardian Interlock’s fees directly with the provider. Rather than repeat a number from a forum post, we are leaving this blank until we can cite where it came from and when we checked it.
What changes the price
- Your state. Program fees and mandated monitoring differ by state.
- Your term. The monthly fee, multiplied by the months the court set, is most of the bill.
- Vehicle. Some installs take longer, and labor is charged accordingly.
- Missed appointments. Late calibrations and lockouts trigger extra fees.
Guardian Interlock has 207 centers on file with us — see coverage by state.
What Guardian Interlock can charge you, and where
A published price list is only half the story. The other half is whether you could walk to a competitor and whether your state caps the fee at all. Both are measurable, and both differ by provider.
In 4 of the states where Guardian Interlock operates, the fee is not theirs to set: the state publishes a limit or a fee schedule. If you are in one of these, a higher quote is worth questioning.
| State | What the state sets | Published figures |
|---|---|---|
| California | A sliding scale by income | Removal free by law. source |
| Oklahoma | A fee schedule | Install up to $350. Monthly up to $114.99. Removal up to $150. source |
| Maryland | Published guidance | Install up to $150. Monthly up to $100. Removal free by law. source |
| New Mexico | Published guidance | Install up to $150. Monthly up to $80. Removal free by law. source |
Cost questions
How much does an ignition interlock device cost per month?
You pay for an interlock in three parts: a one-time installation fee, a recurring monthly fee that covers the device lease and monitoring, and a removal fee at the end of your term. The monthly fee is the part most people underestimate, because it is charged for every month the device stays in the car.
Monthly pricing is set by the provider and varies by state, so the only honest answer is a state-level one. See our state cost breakdown for the range where you live.
What is the cheapest ignition interlock device?
The cheapest device is rarely the cheapest program. Providers advertise a low installation price and recover it through the monthly lease, calibration visits, and the removal fee — so two providers with the same headline price can differ by hundreds of dollars over a 12-month term.
Compare the full term cost, not the install price: installation + (monthly x months) + removal, plus any state-mandated monitoring fees.