The Ultimate Unit Converter Cheat Sheet for Australians

Australia went metric in 1974. It was a whole thing. We changed our road signs, our cookbooks, our ruler markings, and — eventually — our brains.

But here's the catch: the internet didn't get the memo.

American recipes still list butter in sticks. Netflix shows reference Fahrenheit like it's a perfectly normal unit. Amazon lists product dimensions in inches. American friends text you their running pace in minutes-per-mile. Your car's tyre placard might show PSI. And if you're watching any US home renovation show, you'll hear "square footage" used as if square metres never existed.

This guide is the cheat sheet you've been bookmarking in your head for years. Every conversion a modern Australian actually needs, in one place, with the mental shortcuts that make them stick.

Cooking: The Conversions That Actually Matter

American cooking is the biggest culprit. Their cups, tablespoons, and fluid ounces are close to (but not exactly) our metric equivalents, which makes adapting recipes a minor adventure.

Volume (liquids and dry ingredients)

The tablespoon trap: This is genuinely worth knowing. Australian tablespoons are 20 mL; American ones are 15 mL. If a US baking recipe calls for 3 tablespoons of baking powder, using an Australian tablespoon gives you 60 mL instead of 45 mL. That's not nothing. Use a proper metric measure rather than your tablespoon from the drawer.

Weight (baking)

Mental shortcut for pounds: Divide by 2.2. So a 6-pound roast is about 2.7 kg. If you can't be bothered dividing by 2.2, dividing by 2 and knocking off a bit works for a rough guess.

Oven temperatures

Quick mental formula for weather: Subtract 32, then divide by 1.8. Or for a rough shortcut: subtract 32, then halve it. So 68°F minus 32 = 36, halved = 18°C. Close enough for the weather. Note: this halving shortcut gets less accurate the higher the temperature goes — for oven temps, use the table above or the ÷1.8 formula.

Temperature: Weather and Everything Else

Americans love Fahrenheit for weather. This becomes a problem the moment you follow a US-based weather account, travel blog, or climate data source.

Distance, Height, and Length

Miles, feet, inches, and yards are a package deal. Once you're watching American content regularly, you'll hear all four constantly.

Speed: 60 mph = 97 km/h (basically 100 km/h). The US speed limit on highways is typically 70–75 mph, which is 113–120 km/h. No wonder American driving feels fast.

Height: The feet-and-inches system for describing people trips up Australians every time. A quick-reference: 6 feet = 183 cm. 5'6" = 168 cm. 5'0" = 152 cm. If someone says they're "around six foot two," they're 188 cm.

Area: Square Feet, Acres, and Hectares

If you've looked at property listings in the US or UK, you've seen "square footage." And if you're curious about land area (especially rural property or farming), you'll hit acres and hectares.

Quick shortcut: To convert square feet to m², divide by 10.7 (or multiply by 0.093). So a 1,500 sq ft apartment is roughly 140 m².

Weight: Pounds, Stones, and Ounces

The UK and older Australian usage still references stones for body weight. Americans use pounds. Both are inconvenient.

Pounds to kg shortcut: Divide by 2.2. Or for a rougher mental calculation: halve the number and subtract 10%. So 180 lbs halved = 90, minus 9 = 81 kg. Close enough.

Pressure: Tyre PSI and kPa

Your car's door placard might list tyre pressure in kPa (kilopascals). Your tyre gauge at the servo might show PSI. These are not the same thing, and driving on underinflated tyres is genuinely risky.

Conversion: PSI x 6.895 = kPa. Or roughly: PSI x 7 = kPa. So if your door placard says 220 kPa, that's 220 / 7 = 31 PSI. Most passenger cars run 30–35 PSI.

The Handy Ones You Forget Until You Need Them

Fuel efficiency: mpg vs L/100km

American cars quote fuel economy in miles per gallon (mpg). Australian cars use litres per 100 km (L/100km). Higher mpg is better; lower L/100km is better. They're inverse relationships, which adds to the confusion.

• 30 mpg = 7.8 L/100km (reasonable for a petrol car)
• 40 mpg = 5.9 L/100km (efficient)
• 50 mpg = 4.7 L/100km (hybrid territory)

Conversion: Divide 235 by the mpg figure to get L/100km. So 35 mpg = 235 / 35 = 6.7 L/100km.

Planning a road trip and want to work out your actual fuel costs? Our Fuel Cost Calculator does it properly in Australian prices and distances.

Clothing sizes

Australian clothing sizes roughly follow UK sizing for women (so a US size 8 = Australian size 12), and US sizing for men's waist measurements. This is inconsistent enough that you really should check each retailer's specific size guide rather than relying on conversion charts.

Paper sizes

Australia uses ISO A4 (210 × 297 mm). America uses "Letter" (216 × 279 mm). If you're printing an American PDF on Australian A4, it'll fit — but might have slightly wider margins. Worth knowing if you're printing official documents or anything that needs to look right.

Electrical voltage

Australia runs on 230V / 50Hz. The US uses 120V / 60Hz. This matters if you're bringing appliances back from the US. Hair dryers, straighteners, and older chargers are often voltage-specific and will fry on Australian power (or at minimum run very badly). Most modern laptops and phone chargers are auto-switching (look for "100–240V" on the label). Always check before plugging in.

The Ones You Can Wing

Some conversions are close enough that the approximation never really matters in daily life:

• 1 yard ≈ 1 metre (close enough for casual distances)
• 1 US cup ≈ 1 Australian cup (10 mL difference, irrelevant for most cooking)
• 1 mile ≈ 1.6 km (easier than the precise 1.609)
• 1 kg ≈ 2.2 lbs (works fine for estimating)

And the ones where precision does matter:

• Oven temperatures — 25°C off can wreck a cake
• Tyre pressure — affects safety and fuel economy
• Voltage — getting this wrong destroys appliances
• Australian tablespoons in baking — the 5 mL difference adds up