1. Your tank
Capacity is on the label or the maker’s sheet (1,000, 1,200, 1,300 and 2,500 litres are common). Inside height is how deep the oil would be if the tank were brim full: push the stick to the bottom and mark the inside of the top (on a bunded tank, the inner tank’s top), or use the maker’s sheet.
Depths use the unit picked under inside height. The deepest line is taken as full.
2. Today’s reading
Save a reading every week or two (not just after a delivery) and the calculator uses your own rate instead of the estimate below.
3. How much you use
Best figure: add up the litres delivered over the last 12 months. Most homes use about 1,500 to 3,000 litres a year. The calculator spreads it over the year with winter months using about four times as much as summer ones.
4. Ordering
Your oil
Expected level on the 1st of each month
| Date | Litres | Level |
|---|
An estimate from your usage, assuming an ordinary winter and no delivery.
Dipstick chart
Dipstick chart for your tank
Questions
How do I work out how much oil is in my tank?
Push a clean stick straight down through the filler to the bottom, pull it out and measure the wet part in cm. If the tank has flat sides, the share of the tank that is full is the oil depth divided by the inside height. If it is round or oval and lying on its side it is not a straight line: a quarter of the way up it holds about 20%, half way 50%, three quarters about 80%. The calculator does this sum for you.
| Depth (share of height) | Oil (share of capacity) |
|---|---|
| 10% | 5% |
| 20% | 14% |
| 25% | 20% |
| 30% | 25% |
| 40% | 37% |
| 50% | 50% |
| 60% | 63% |
| 70% | 75% |
| 75% | 80% |
| 80% | 86% |
| 90% | 95% |
How long will 1,000 litres of heating oil last?
It depends on the home and the time of year. For a home that uses 2,000 litres a year, 1,000 litres bought on 1 November lasts about 120 days in this calculator’s seasonal model, because winter months burn several times more than summer ones. The same 1,000 litres from 1 May lasts about 236 days.
| Uses a year | 500 L from 1 Nov | 1,000 L from 1 Nov | 1,000 L from 1 May |
|---|---|---|---|
| 1,500 L | 82 days | 168 days | 274 days |
| 2,000 L | 63 days | 120 days | 236 days |
| 2,500 L | 51 days | 97 days | 213 days |
| 3,000 L | 43 days | 82 days | 194 days |
How much heating oil does a house use in a year?
Most UK households use between about 1,500 and 3,000 litres a year, and winter use can be up to four times summer use. The best figure for your home is the total litres delivered over the last twelve months.
When should I order heating oil?
Order before the tank gets low rather than when it runs dry. Delivery can take a week or more in a cold snap, and running the tank dry can draw sludge into the pipe and leave air in the boiler’s fuel line. The calculator gives an order-by date that allows for your delivery time and the level you want to keep in reserve.
How much oil should I order to fill my tank?
Order the space between what is in the tank now and the level your supplier will fill to, which is usually a little under the brim, then round down. Many suppliers have a minimum order, often around 500 litres. The calculator rounds the top-up down to the nearest 50 litres.
Is it accurate?
As accurate as the measurements. Real tanks have rounded corners, ribs and baffles, so a shape-based answer can be a few percent out; the maker’s chart, if you can get it, is better (pick “I have the maker’s chart”). Usage is a seasonal estimate: a cold January burns more. Saving a reading every week or two gives you your own rate.
Where is my data kept?
Only in this browser on this device. There are no accounts and nothing is sent anywhere.