Everyday reference

What things come to in the new units (3 significant digits). Round is what a product, limit or setting would probably become: small values go to the nearest whole number, half, third or quarter (within 3%); large values (30 and over) go to a number ending in 0 or 6 - a multiple of six - at whatever scale suits (36, 56, 1X0, 800). Speed limits are the exception: they take the nearest whole number (see Speed limits and changeover). Left blank for natural values (body temperature, speed of sound) and where the value is already round. US gives the size in US customary units, for things measured that way in the US. Prefixes are used where the plain unit gives awkward numbers: tc ÷1,000, bc ÷100, uc ÷10, tq ×1,000.

t↓li (1/1,000 lib) ≈ 1.03 g and t↓cu (1 dig³) ≈ 1.03 mL - the new gram and millilitre
ir (iter, 1,000 paces = t↑p) ≈ 2.51 km; t↑op (1,000 opus) ≈ 53.6 kJ; t↑pr (1,000 pres) ≈ 17.5 kPa

Length

Thing	SI	US	Dozenal	Round
Credit card (long side)	85.6 mm	3.37 in	8;5X di	8;6 di
Pencil-case ruler	15-20 cm	6 in	0;12X-0;17X p	0;2 p (a span, 24.2 cm)
Desk ruler	30 cm	12 in	0;259 p	0;3 p (36.3 cm)
A4 page (long side)	297 mm		2;55 un	2;6 un
Adult height	1.70 m	5 ft 7 in	1;21 p	1;2 p
Tall person (6 ft)	1.83 m	6 ft	1;31 p	1;3 p
Door height	2.04 m	6 ft 8 in	1;4X p	1;5 p
Car length	4.5 m	15 ft	3;12 p	3;1 p
Cricket pitch	20.12 m	22 yd	11;X p	(keeps 22 yd)
Olympic pool	50 m	164 ft	2X;5 p	30 p
1 km	1 km	0.62 mi	494 p	496 p (1.002 km)
Marathon	42.195 km	26.2 mi	14;99 ir	(keeps 42.195 km)
Sydney–Melbourne (straight line)	713 km	443 mi	1E8 ir
Letter page (long side)	279 mm	11 in	2;38 un	2;4 un (P5 replaces Letter and A4)
Ceiling height	2.44 m	8 ft	1;82 p	1;8 p
Building sheet (plasterboard, plywood)	1,200 × 2,400 mm	4 × 8 ft	0;9XE × 1;79E p	0;X × 1;8 p (1,210 × 2,421 mm)
Stud spacing (wide)	600 mm	24 in	0;4E6 p	0;5 p (605 mm)
Stud spacing (close)	450 mm	16 in	0;387 p
Football field (US)	91.4 m	100 yd	52;E p	(keeps 100 yd)
Mile	1.61 km	1 mi	0;784 ir (783;E p)	780 p (1.60 km)

Races and sport

Exact conversions, and the round distance that would likely replace each one (rounded, not converted - see Speed limits and changeover). Traditional distances tied to history (marathon, cricket pitch) keep their length.

Distance now	Exact	Likely new distance	That is
25 m pool	15;3 p	16 p	26.1 m
50 m pool	2X;5 p	30 p	52.3 m
100 m sprint	58;X p	60 p	104.6 m
200 m	E5;8 p	100 p	209.2 m
400 m (1 lap)	1XE;5 p	200 p (1 lap)	418.3 m
800 m	39X;9 p	400 p	836.7 m
1,500 m / mile	720;8 p / 783;E p	700 p	1,464 m
5 km (parkrun)	1;EE ir	2 ir	5.02 km
10 km	3;EX ir	4 ir	10.04 km
Half marathon	8;4X ir	keeps 21.1 km
Marathon	14;99 ir	keeps 42.195 km
Cricket pitch	11;X p	keeps 22 yd

The 100 m becomes the 60-pace sprint; the 5 km and 10 km land almost exactly on 2 and 4 iters

Playing fields

Sizes from the Laws of each game. Markings fixed by those laws keep their size, as the cricket pitch does: changing them changes the game, and every ground in the world would have to be re-marked at once. Only the soccer pitch, which already varies from ground to ground, gets a round size.

Thing	SI	US	Dozenal	Round
Soccer pitch (FIFA size)	105 × 68 m	115 × 74 yd	60;3 × 3X;X p	60 × 40 p (104.6 × 69.7 m)
Soccer pitch (area)	7,140 m²	1.76 acres	1;E6 ag	2 ag (60 × 40 p, exact)
Soccer pitch (allowed range)	90-120 × 45-90 m	100-130 × 50-100 yd	52-6X;7 × 27-52 p
Penalty area	16.5 × 40.3 m	18 × 44 yd	E;44 × 23;9 p	(keeps 18 × 44 yd)
Goal area	5.5 × 18.3 m	6 × 20 yd	3;95 × 10;7 p	(keeps 6 × 20 yd)
Penalty spot (from goal line)	11 m	12 yd	7;6E p	(keeps 12 yd)
Centre circle (radius)	9.15 m	10 yd	6;37 p	(keeps 10 yd)
Soccer goal	7.32 × 2.44 m	8 yd × 8 ft	5;06 × 1;82 p	(keeps 8 yd × 8 ft)
Tennis court (doubles)	23.77 × 10.97 m	78 × 36 ft	14;4 × 7;68 p	(keeps 78 × 36 ft)
Tennis court (singles width)	8.23 m	27 ft	5;80 p	(keeps 27 ft)
Tennis service line (from net)	6.40 m	21 ft	4;4X p	(keeps 21 ft)
Tennis net (centre / posts)	0.914 / 1.07 m	3 ft / 3 ft 6 in	7;67 / 8;X1 un	(keeps 3 ft / 3 ft 6 in)
Cricket pitch (stumps to stumps)	20.12 m	22 yd	11;X p	(keeps 22 yd)
Cricket pitch (width)	3.05 m	10 ft	2;12 p	(keeps 10 ft)
Popping crease (in front of the stumps)	1.22 m	4 ft	X;0E un	(keeps 4 ft)
Stumps (height × width)	71.1 × 22.9 cm	28 × 9 in	5;X6 × 1;X8 un	(keeps 28 × 9 in)
Cricket boundary (from the pitch centre, men's internationals)	59.4-82.3 m	65-90 yd	34;E-48;8 p	(set by each ground)

The round soccer pitch, 60 × 40 paces, is exactly 2 agers, and its length is the 60-pace sprint

Mass

Thing	SI	US	Dozenal	Round
Egg	60 g	2.1 oz	4X;6 t↓li	50 t↓li
Apple	150 g	5.3 oz	102 t↓li	100 t↓li
1 L of water	1 kg	2.2 lb	0;693 li
Newborn baby	3.5 kg	7.7 lb	1;E9 li	2 li
Checked-in bag limit	23 kg	50 lb	11 li
Adult	75 kg	165 lb	36;4 li	36 li
Small car	1,300 kg	2,900 lb	512 li	500 li
Stick of butter	113 g	4 oz	92;7 t↓li	90 t↓li
Pack of ground beef	454 g	1 lb	0;30X li	0;3 li
Bag of flour	2.27 kg	5 lb	1;34 li	1;3 li
Turkey	6.8 kg	15 lb	3;X1 li

Temperature

Thing	SI	US	Dozenal	Round
Freezer	-18 °C	0 °F	-21;E °t	-22 °t
Fridge	4 °C	39 °F	5;92 °t	5;8 °t
Cool day	15 °C	59 °F	19;7 °t	1X °t
Room	21 °C	70 °F	26;3 °t	26 °t
Warm day	30 °C	86 °F	37;2 °t	36 °t
Body	37 °C	98.6 °F	45;3 °t
Heatwave	45 °C	113 °F	54;X °t	56 °t
Boiling water	100 °C	212 °F	100 °t
Oven (moderate)	180 °C	350 °F	197 °t	1X0 °t

Volume

Thing	SI	US	Dozenal	Round
Teaspoon	5 mL	1 tsp	4;X6 t↓cu	5 t↓cu
Coffee, small (café)	237 mL	8 fl oz	173 t↓cu	170 t↓cu
Coffee, regular (café)	355 mL	12 fl oz	24X t↓cu	250 t↓cu
Coffee, large (café)	473 mL	16 fl oz	325 t↓cu	320 t↓cu
Cup	250 mL	1 cup (237 mL)	184 t↓cu	180 t↓cu
Can of drink (AU)	375 mL		265 t↓cu	260 t↓cu
Wine bottle	750 mL	25.4 fl oz	0;50E cu	0;5 cu
Milk bottle (AU)	2 L		1;16 cu	1;2 cu
Bucket	10 L	2.6 gal	5;78 cu	5;6 cu
Car fuel tank	50 L	13 gal	24;2 cu	24 cu
Bath	150 L	40 gal	70;7 cu	70 cu
Soda can (US)	355 mL	12 fl oz	24X t↓cu	250 t↓cu
Pint glass (US)	473 mL	16 fl oz	325 t↓cu	320 t↓cu
Quart	946 mL	1 qt	0;64X cu
Gallon of milk or gas	3.79 L	1 gal	2;17 cu	2;2 cu
Bucket (US)	18.9 L	5 gal	X;81 cu	X;9 cu

Time

Thing	SI	Dozenal	Round
Heartbeat	0.8 s	0;93 bt
Minute	60 s	1;25 mt
Hour	60 min	0;6 ch (60 mt)
Feature film	2 h	1 ch
Short meeting, lunch break	30 min	0;3 ch (30 mt)
Lesson, meeting	45 min	0;46 ch (46 mt)	0;4 ch (40 min) or 0;5 ch (50 min)
Long meeting, lecture	60 min	0;6 ch (60 mt)
School day	9:00-15:00 (6 h)	460-760 (3 ch)
Working day	9:00-17:00 (8 h)	460-860 (4 ch)
Working week (AU)	38 h	17 ch
Working week (US)	40 h	18 ch
Night's sleep	8 h	4 ch
School year	about 200 days	about 148 days
Year	365.2422 days	265;2XX days
School starting age	5 years	5 years
Adult (voting, driving)	18 years	16 years
Coming of age (21st birthday), US drinking age	21 years	19 years
Retirement age (Australia, US)	67 years	57 years
Average lifetime (world)	73 years, about 26,660 days	61 years, about 13,520 days
Average lifetime (Australia)	83 years	6E years
Century	100 years	84 years	a gro of years (100) is 144 (dec)

Speed

Thing	SI	US	Dozenal	Round
Walking	5 km/h	3 mph	3;EX p/br	4 p/br
Cycling	20 km/h	12 mph	13;E p/br	14 p/br
School zone	40 km/h	25 mph	27;X p/br	28 p/br
Town	50 km/h	30 mph	33;X p/br	34 p/br
Motorway	110 km/h	70 mph	73;8 p/br	74 p/br
Airliner	900 km/h	560 mph	4E9 p/br	500 p/br
Sound	343 m/s	767 mph	6X p/bl
Residential street (US)	40 km/h	25 mph	28;1 p/br	28 p/br
Freeway (US)	105 km/h	65 mph	6E;4 p/br	70 p/br

Fuel use

Decided: fuel use is given in cubs per 100 iters (cu/100 ir, per 361 km dec), the way Australia and Europe use L/100 km. Rule of thumb: the value is about double the L/100 km figure (×2.04 dec).

Why: fuel per distance is the sensible measure, and 100 iters is a similar trip length to 100 km, so the numbers stay whole-ish. Rejected: distance per fuel (iters per cub, like mpg or km/L), judged a poor measure. The US mpg column is kept only as a familiar comparison for people learning the system.

Advantage: fuel for a trip is just the figure times the distance, and the numbers stay close to today's (about double L/100 km).

L/100 km (dec)	US mpg (dec)	cu/100 ir	Like
4	58.8	8;2	hybrid
5	47.0	X;2	small car, highway
6	39.2	10;3	small car
7	33.6	12;3	mid-size car
8	29.4	14;4	family car
10	23.5	18;5	large car, SUV
12	19.6	20;5	ute, 4WD
15	15.7	26;7	large 4WD, towing
20	11.8	34;9	truck, city driving

Electric cars, in t↑op per iter (the energy to drive one iter):

kWh/100 km (dec)	t↑op/ir	Like
12	1X;3	small EV
15	21;4	typical EV
18	26;4	large EV
20	29;9	EV SUV

Energy

Thing	SI	US	Dozenal	Round
Apple (food energy)	400 kJ	95 Cal	7;57 t↑op	7;6 t↑op
Daily food intake	8,700 kJ	2,100 Cal	116 t↑op	120 t↑op
Phone battery	15 Wh	15 Wh	1;01 t↑op	1 t↑op
1 kWh	3.6 MJ	1 kWh	57;2 t↑op	56 t↑op
Daily value (US food labels)	8.37 MJ	2,000 Cal	110 t↑op
Gallon of gasoline	121 MJ	33.7 kWh	1,390 t↑op	1,400 t↑op

Power

Thing	SI	US	Dozenal	Round
LED bulb	10 W	10 W	1;42 u↓vg	1;4 u↓vg
Person at rest	100 W	100 W	1;15 vg
Kettle	2,400 W		22;E vg	23 vg
Small car engine	100 kW	134 hp	794 vg	800 vg
Space heater, US kettle	1,500 W	1,500 W	14;X vg	15 vg

Pressure

Thing	SI	US	Dozenal	Round
Atmosphere	101.3 kPa	14.7 psi	5;97 t↑pr
Car tyre (gauge)	220 kPa	32 psi	10;7 t↑pr	11 t↑pr
Car tyre (US)	241 kPa	35 psi	11;X t↑pr	12 t↑pr

Voltage

Thing	SI	US	Dozenal	Round
AA battery	1.5 V	1.5 V	2;58 u↓im	2;6 u↓im
USB	5 V	5 V	0;830 im
Car battery	12 V	12 V	1;799 im	1;8 im
Mains (AU)	230 V		27;79 im	28 im
Mains (UK, AU older)	240 V		29;03 im	29 im
Mains (US)	120 V	120 V	14;62 im	14;6 im

Current

Thing	SI	US	Dozenal	Round
LED	20 mA	20 mA	2;9X t↓ri	2;9 t↓ri
Phone charger	2 A	2 A	0;1E5 ri	0;2 ri
Kettle (AU, UK)	10 A		0;992 ri	0;X ri
UK plug fuse	13 A		1;084 ri
Socket circuit (EU, AU)	16 A		1;376 ri	1;4 ri
Socket circuit (US)	20 A	20 A	1;765 ri	1;8 ri
Oven, EV charger	32 A	32 A	2;731 ri	2;8 ri

Notes:

Temperatures, heights, speeds and voltages come out in comfortable numbers
Café coffee sizes (8, 12 and 16 oz: 170, 250 and 320 t↓cu) are the cup's brim capacity, the way cups are sold. The drink served is less, depending on milk and froth: about 200 mL in a small, 300 mL in a regular
Energy and pressure need the tq prefix for everyday sizes (opus and pres are small); food labels in t↑op
A feature film is 1 chime; a working day and a night's sleep are 4 chimes each
A 0;X p building sheet spans two 0;5 p stud gaps, as a 1,200 mm sheet spans two 600 mm gaps. The close spacing (450 mm, 16 in) has no round value nearby: 0;4 p is 484 mm