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Everyday Estimation


Collage of space view of earth, areal view of farmland, swimming pool, and close-up view of a nickel
Credit: Pixabay/Pexels

Estimation is more than taking a guess!  The ability to interpret measurement scales and approximate a quantity are essential Science, Technology, Engineering, and Mathematics (STEM) competencies. This important approximation tool helps interpret the world around us:

  • Comparisons – relative size or quantity
  • Magnitude of small and large numbers
  • Ordering
  • Spatial reasoning
  • Sensemaking
  • Checking for reasonableness

Estimation is used when it’s not important to find an exact measurement. Estimations are also valuable when developing a hypothesis and evaluating if experimental data results are reasonable. Refining estimation skills through practice improves proficiency (and accuracy)!

Educators are invited to attend the free Metric Estimation professional development webinar, which presents the Metric Estimation Game as a model learning activity designed to develop and reinforce estimation skills, select and use appropriate measurement tools, and determine measurement unit quantity, scale, and magnitude. Explore these tables to learn more about approximate measurements and develop reference points.

Two photos show liter models: A paper cube on the left, and a plastic cube with colored blocks inside on the right.
Liter models can help build estimation skills.
Credit: NIST


6 Rg Earth
1300 kg Small Automobile
70 kg Large Dog (Great Dane)
15 kg Bicycle
5 kg Cat
850 g Baseball Bat
270 g NCAA Volleyball
150 g Cell Phone
100 g Medium Red Delicious Apple
46 g Golf Ball
5 g Nickel Coin ($0.05)
2.5 g Penny Coin ($0.01)
1 g Currency Note (regardless of denomination)
600 mg Cotton Ball

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150 Gm Distance from Earth to Sun
40 Mm Circumference of Earth
43 km NIST (Gaithersburg, MD) to The Whitehouse
11 km Mariana Trench
90 m Football Field (Length)
3.7 m Interstate Highway Lane (Width)
1 m NCAA Volleyball Net (Width)
153 mm Currency ($5 Bill)
66 cm NCAA Volleyball (Circumference)
19 cm Pencil
1 mm Thickness of a Dime
7 µm Average Human Hair

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162 m²
(9 m) x (18 m)
NCAA Volleyball Court
616 cm²
(22 cm) x (28 cm)
Office Paper
550 mm2
(25 mm x 22 mm)
First Class U.S. Postage Stamp

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1 ML Olympic Swimming Pool
235 L Bathtub
5 L Blood in Human Body
4L Full Human Stomach
3.79 L Gallon of Milk
500 mL Air per Breath at Rest (Tidal Volume) Adult Human Male
400 mL Air per Breath at Rest (Tidal Volume) Adult Human Female
355 mL Soda Pop Can
200 mL Juice Box
80 mL Empty Human Stomach
15 mL Eye Drop Bottle

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5500 °C Surface of the Sun
100 °C Water Boils
40 °C Sweltering Day
37 °C Human Body
30 °C Hot Day
20 °C Comfortable Room
10 °C Cold Day
0 °C Water Freezes



Created February 4, 2010, Updated September 26, 2023