New category: Fuel Consumption
Fuel economy never fit cleanly into the existing Speed or Volume tabs, because it isn't really a length, a weight, or a plain volume — it's a rate that combines distance and fuel volume together, and different countries express that rate in genuinely different directions. Giving it a dedicated category means the from/to dropdowns, the live all-units table, and the popular-conversion chips all work the same way they already do for Length or Temperature, just applied to this fourth pair of units.
As with every other category on the page, switching to Fuel Consumption also updates the live table underneath the result, so entering one mpg figure shows its equivalent in all four units side by side at once — useful for comparing a US-market spec sheet against a UK or EU one without doing four separate lookups.
mpg (US), mpg (UK), L/100km, or km/L — which one do you need?
Which unit you'll want mostly comes down to where a spec sheet or dashboard was written. US car listings and window stickers use mpg (US). UK and some Commonwealth sources use mpg (UK), which is not the same scale, because the underlying gallon is a different size (3.785 L for US vs. 4.546 L for UK, about 20% larger). Most of continental Europe uses L/100km. Some other regions, and some enthusiast or motorcycle contexts, prefer km/L instead.
| mpg (US) | mpg (UK) | L/100km | km/L |
|---|---|---|---|
| 25 | ~30 | ~9.4 | ~10.6 |
| 40 | ~48 | ~5.9 | ~17.0 |
| 55 | ~66 | ~4.3 | ~23.4 |
Because mpg and L/100km run in opposite directions, a small mpg improvement near the top of the scale barely moves the L/100km figure, while the same mpg improvement near the bottom of the scale moves it a lot — the relationship curves rather than scaling in a straight line. That's exactly the kind of thing a live converter is for: rather than eyeballing which direction is "better" across four different scales, enter the one number from the spec sheet in front of you and read the other three off the result.
New mini-tool: lb + oz → kg
The existing single-field lb → kg card only ever accepted a plain decimal pound value, so a reading that's naturally split across two units — like a newborn weight, a kitchen scale readout, or a shipping label — needed the ounces converted to a fraction by hand before it could be typed in. The new card removes that step: enter the pounds in one field and the ounces in the other, and the tool combines them internally before applying the kg conversion.
Under the hood it's the same math as before — ounces divided by 16 to get a fractional pound, added to the whole pounds, then multiplied by 0.453592 — just wired up as its own two-field card instead of requiring the fraction to be pre-computed. As an illustrative example, a package weighing 12 lb 6 oz works out to 12.375 lb total, or roughly 5.61 kg.
Why this is the same pattern as ft/in → cm
Both new mini-tools use the same shape the converter already had for height: two related units describing a single quantity, combined before the metric multiplier is applied rather than after. The ft/in → cm card converts feet to inches, adds the leftover inches, then multiplies by 2.54. The lb + oz → kg card converts ounces to a fraction of a pound, adds it to the whole pounds, then multiplies by 0.453592 — same structure, different units and constant.
That's a useful thing to know if you're scanning the tools section for the first time: any card phrased as "unit A + unit B → target" is doing this same two-step combine-then-convert internally, and any decimal-only card (like the plain lb → kg one) expects the value pre-combined. Knowing which type of field you're looking at saves a trip to a calculator before you even reach the converter.