1,000 litres is almost always cheaper per litre than 500 litres. The typical saving is 2–5p per litre, which translates to £11–£28 saved on the second 500L of a 1,000L order. If your tank holds 1,000L or more and you'll use it within 18 months, ordering 1,000L beats ordering 500L twice.
Why larger orders are cheaper per litre
Heating oil delivery has a significant fixed cost. The tanker, driver, fuel for the vehicle, insurance, and depot time. Whether a supplier delivers 500 litres or 1,000 litres to your address, most of those fixed costs are the same. By spreading those costs across more litres, larger orders achieve a lower total cost per litre.
This is why the price per litre almost always decreases as volume increases. Suppliers explicitly price this into their tariff structures, and it's one of the reasons why comparing on per-litre price alone can be misleading if you're comparing quotes at different volumes.
Typical price difference: 500L vs 1000L
| Volume | Typical ppl (May 2026) | Total cost inc VAT | Saving vs 500L |
|---|---|---|---|
| 500 litres | 113–118p/L | £593–£620 | — |
| 750 litres | 110–115p/L | £866–£907 | £10–£22 vs 2× 500L |
| 1,000 litres | 108–113p/L | £1,134–£1,187 | £20–£56 vs 2× 500L |
| 1,500 litres | 106–110p/L | £1,668–£1,733 | £60–£120 vs 3× 500L |
| 2,000 litres | 105–109p/L | £2,205–£2,290 | £90–£160 vs 4× 500L |
Prices are indicative national averages for May 2026. Your local price may differ — get a live quote for your postcode.
When 500 litres makes sense
Despite the per-litre price advantage of larger orders, there are genuine reasons to order 500L rather than 1,000L:
- Tank capacity, if your tank only holds 500–700 litres, you can't order more than it holds. Never overfill an oil tank.
- Running very low in winter, if you've nearly run out, ordering 500L to get through the cold snap and then a full 1,000L top-up in summer is a sensible two-stage approach.
- Cash flow: the upfront cost of 1,000L at current prices is over £1,100 inc VAT. For some households, the cash flow impact of a larger order outweighs the per-litre saving.
- Short-term property, if you're renting or selling and won't be there long enough to use 1,000L, don't over-order.
When 1,000 litres is clearly better
- Your tank capacity is 1,000L or more (the most common UK domestic tank size)
- You use at least 1,000 litres per year (any medium or large home will)
- You're buying in summer: the per-litre saving compounds with the seasonal price advantage
- You want to minimise the number of deliveries and associated costs
Order 1,000L in July or August and you capture two savings simultaneously: the volume discount (2–5p/L cheaper than 500L) and the seasonal discount (10–20p/L cheaper than winter prices). On a 1,000L order, that combined saving can be £120–£250 compared with ordering 500L in December.
What about 2,000 litres?
Orders above 2,300 litres are classified as commercial by HMRC and require you to confirm the fuel is for domestic use. Most domestic households don't need 2,000L at once. Typical annual usage is 1,500–2,500 litres, but if you have a large tank (2,500L+) and a big property, a 2,000L summer fill is legitimate and will save an additional 3–5p per litre versus 1,000L.
Note that not all suppliers will deliver 2,000L as a domestic order. Check with your supplier before ordering.
How to compare accurately
When comparing quotes, always compare at the same volume. A quote for 1,000L from Supplier A should be compared to a quote for 1,000L from Supplier B, not Supplier B's 500L quote, even if that's what you initially planned to order. The total cost including VAT is the only meaningful number to compare.
Our quote tool on the PriceTank homepage shows all supplier prices at the same volume so you're always comparing apples to apples.
Enter your postcode and select 500L or 1000L to see exactly what each supplier charges today.