# OilTankCharts > Free heating-oil tank charts, calculators, and guides: convert tank-gauge inches to > gallons for common tank sizes, estimate how many days of oil you have left, right-size > a replacement tank, and learn to read your gauge. Charts are computed from tank geometry > and checked by build-time assertions. No account, works offline. > > For: US heating-oil homeowners reading a tank gauge or planning a delivery or tank > replacement, and the oil-service techs who help them. ## Calculators - [Tank level and volume calculator](https://oiltankcharts.com/calculators/tank-volume/): Turn a tank level in inches into gallons, or get total capacity from the dimensions. - [Heating oil usage calculator](https://oiltankcharts.com/calculators/heating-oil-usage/): Estimate the gallons you burn per day from two gauge readings. - [How long will my oil last](https://oiltankcharts.com/calculators/how-long-will-oil-last/): Turn your current gauge reading into days of oil remaining. - [Buried tank size identifier](https://oiltankcharts.com/calculators/which-buried-tank/): Find a buried tank's size from a delivery and before-and-after readings. - [What size tank do I need?](https://oiltankcharts.com/calculators/tank-size/): Right-size a replacement tank from your yearly oil use. - [Burner fuel use and nozzle chart](https://oiltankcharts.com/calculators/burner-fuel-use/): Look up gallons per hour from your nozzle size and pump pressure. - [Nozzle converter (for techs)](https://oiltankcharts.com/calculators/nozzle-converter/): Convert nozzle flow between pump pressures and gallons per hour. ## Tank charts (inches to gallons) - [275 gallon vertical chart](https://oiltankcharts.com/charts/275-gallon-vertical/) - [275 gallon horizontal chart](https://oiltankcharts.com/charts/275-gallon-horizontal/) - [330 gallon vertical chart](https://oiltankcharts.com/charts/330-gallon-vertical/) - [330 gallon horizontal chart](https://oiltankcharts.com/charts/330-gallon-horizontal/) - [550 gallon underground chart](https://oiltankcharts.com/charts/550-gallon-underground/) - [1000 gallon underground chart](https://oiltankcharts.com/charts/1000-gallon-underground/) - [500 gallon underground chart](https://oiltankcharts.com/charts/500-gallon-underground/) - [Fiberglass ball tanks](https://oiltankcharts.com/charts/fiberglass-ball-tanks/) - [Roth tank sizes](https://oiltankcharts.com/charts/roth-tanks/) - [Granby tank sizes](https://oiltankcharts.com/charts/granby-tanks/) ## Guides - [How to stick an oil tank](https://oiltankcharts.com/guides/how-to-stick-an-oil-tank/): Measure inches with a dipstick and convert to gallons. - [Reading an oil tank gauge](https://oiltankcharts.com/guides/reading-an-oil-tank-gauge/): What the float gauge shows and how far to trust it. - [Petrometer gauges: read, pump, fix](https://oiltankcharts.com/guides/petrometer-gauge/): Read, troubleshoot, and replace a Petrometer float gauge. - [WiFi and smart oil tank gauges](https://oiltankcharts.com/guides/wifi-oil-tank-gauge/): How ultrasonic tank gauges work, what they miss, and whether one will work on your tank. - [Replacing an oil tank gauge](https://oiltankcharts.com/guides/oil-tank-gauge-replacement/): Match the gauge to your tank depth, avoid the combo vent alarm trap, and what the job involves. - [Oil tank whistle (vent alarm)](https://oiltankcharts.com/guides/oil-tank-vent-alarm/): What the vent whistle means and why a silent one is a problem. - [What size is my oil tank?](https://oiltankcharts.com/guides/what-size-is-my-oil-tank/): Identify your tank's size from its shape and dimensions. - [Heating oil K-factor explained](https://oiltankcharts.com/guides/heating-oil-k-factor/): How oil companies use a K-factor to schedule your deliveries. - [When to order heating oil](https://oiltankcharts.com/guides/when-to-order-heating-oil/): The gauge level to reorder at so you never run dry. - [Why a 275 tank holds about 240](https://oiltankcharts.com/guides/why-a-275-tank-holds-240/): Why a full 275 gallon tank gives only about 240 usable gallons. - [How long do oil tanks last?](https://oiltankcharts.com/guides/how-long-do-oil-tanks-last/): Typical tank lifespans and the signs it is time to replace. - [Oil tank replacement cost](https://oiltankcharts.com/guides/oil-tank-replacement-cost/): What a new tank runs, what drives the price, and the one-day swap. - [Oil tank removal and disposal](https://oiltankcharts.com/guides/oil-tank-removal/): Aboveground haul-away vs a buried tank with testing, permits, and cleanup risk. - [Water in your oil tank](https://oiltankcharts.com/guides/water-in-oil-tank/): How water gets in, why it harms your system, and how to clear it. - [Outdoor oil tanks in winter](https://oiltankcharts.com/guides/outdoor-oil-tank-winter/): Stop an outdoor tank from gelling when temperatures drop. - [No gauge, no stick: tracking oil](https://oiltankcharts.com/guides/track-oil-without-a-gauge/): Track your level by usage when you cannot dip the tank. - [Oil tank reading for a closing](https://oiltankcharts.com/guides/oil-tank-reading-for-closing/): Measure and value the leftover oil for a home sale. ## About this data - Method: chart and calculator values are computed from nominal tank geometry (231 cubic inches per gallon, with a dished-head allowance) and verified by build-time assertions — nothing is copied from manufacturer tables and nothing is fabricated. - Verification: charts are regenerated and re-asserted on every build; current data version 2026-07-27. - Sourcing: the gallons-per-cubic-inch constant and tank geometry are standard; per-tank capacities are calibrated to published manufacturer capacities where available. - Corrections and scope: see https://oiltankcharts.com/about/ for methodology and how to report a correction. Tanks vary by maker and age — cross-check any reading against your tank's data plate. - Cite as: OilTankCharts (oiltankcharts.com).