Free Key Fob and Car Battery Tools
Finders, calculators and checkers for car keys, coin batteries and car batteries. Every tool is free, runs in your browser and needs no sign-up.
Key fob tools
Coming soonKey Fob Battery FinderFind the right coin battery for your car key in seconds. Choose your make, model and year to see the battery for each key style.
Coming soonKey Fob Replacement Cost CalculatorEstimate what a new key fob will cost, including the part, key cutting and programming, and compare dealer, locksmith and online routes.
Coming soonKey Fob Programming Cost CalculatorCheck whether you can program a key fob yourself and see typical dealer and locksmith programming prices for your make and key type.
Coming soonKey Fob FCC ID Match CheckerCheck whether a replacement key fob matches your original by FCC ID, button count and part number before you buy.
Coming soonKey Fob Frequency LookupSee which frequency band your key fob most likely uses, based on market, make and model year, and learn how to confirm it.
Coming soonDealer vs Locksmith Key Fob ChooserAnswer four quick questions to see whether the dealer, a locksmith or a do-it-yourself fix is the best way to sort out your key fob.
Coming soonKey Fob Low Battery CheckerTick your key fob symptoms to find out whether a weak battery is the likely cause, or whether the fault is in the fob or the car.
Coin battery tools
Coming soonCoin Battery Cross ReferenceLook up equivalent names for CR2032, CR2025, CR2450 and other coin cells, and check whether two sizes can be swapped in a key fob.
Coming soonButton Battery Size FinderEnter the diameter and thickness of an unmarked button battery to find the matching coin cell, its voltage and its other names.
Car battery and starting tools
Coming soonCar Battery Group Size FinderLook up the dimensions of any common BCI battery group size, or enter your battery tray measurements to see which group sizes fit your car.
Coming soonCar Battery Date Code DecoderEnter the date code from your car battery to see when it was made, how old it is and whether it is time to test or replace it.
Coming soonCar Battery Voltage CheckerEnter your multimeter reading to see your car battery’s state of charge and whether the alternator is charging as it should.
Coming soonCar Battery Charging Time CalculatorEstimate how long your car battery will take to charge from its current level with a 2 amp, 10 amp or any other charger.
Coming soonJump Starter Size CalculatorFind out how many peak amps your jump starter needs for your engine size, fuel type and climate before you buy.
Coming soonRemote Start Cost CalculatorEstimate what an aftermarket remote starter will cost installed, including the kit, bypass module and labor for your type of car.
About these tools
We built these tools to answer the questions our readers ask most: which battery a key takes, what a replacement should cost, whether a key can be programmed at home and how healthy a car battery is. The data comes from owner’s manuals, standard battery specifications and typical US shop prices. Results are estimates and starting points, so always confirm against your own key, battery or a written quote before you buy.