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Online Tape Measure — Read Feet, Inches and Centimeters

A 25-foot tape drawn at real size, inches on top and centimeters below. Tap the tape to read a mark.

Marker at 0 in

  • Stud marks every 16 in
  • Truss marks every 19.2 in
  • Foot markers

Tap or click the tape to place the marker. Scroll sideways to see all 25 feet. Calibrate first so the tape is true to size.

Detecting device...
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Online tape measure

How to read this tape measure

The top edge is in inches. The longest lines mark whole inches, then half inches, quarters, eighths and, shortest of all, sixteenths. Every 12 inches a red F marker shows the foot, and red boxes every 16 inches mark standard stud spacing. The bottom edge shows centimeters and millimeters. Measured a room? The square footage calculator turns your room measurements into square feet.

Related guides: How to Read a Tape Measure · Lumber Sizes: Actual vs Nominal Dimensions Chart

How to use it

  1. Tap Calibrate and match a bank card so the tape is true to size.
  2. Hold the object against the screen with one end at the 0 hook.
  3. Tap the tape at the other end to read the length in feet, inches, fractions and cm.

Good to know

  • A standard US tape measure reads to 1/16 inch; 1/16 in = 1.59 mm.
  • Stud marks every 16 inches match the most common US wall framing, 16 inches on center.
  • The small black diamonds every 19.2 inches split 8 feet into five equal spaces for joists and trusses.
  • 25 feet = 300 inches = 7.62 meters.

Stud and truss marks in the first 8 feet

Where the special marks fall on a tape, in inches and in feet and inches:

MarkPositions (inches)In feet and inches
Foot marker (every 12 in)12, 24, 36, 48, 60, 72, 84, 961′, 2′, 3′ … 8′
Stud mark (every 16 in)16, 32, 48, 64, 80, 961′4″, 2′8″, 4′, 5′4″, 6′8″, 8′
Truss diamond (every 19.2 in)19.2, 38.4, 57.6, 76.8, 961′7.2″, 3′2.4″, 4′9.6″, 6′4.8″, 8′
24-inch spacing24, 48, 72, 962′, 4′, 6′, 8′
  • US framing is usually laid out at 16 or 24 inches on center; the tape's marks save measuring each stud.
  • Metric tapes mark every 10 cm in red and label each meter, as on the bottom scale here.
Guide

Three ways to calibrate

1

Auto-detect your device

The ruler recognizes about 130 phones, tablets, laptops and monitors, including iPhones, Galaxy phones, Pixels and MacBooks.

Instant±1%
2

Enter your screen size

Enter your screen's diagonal size (for example, 15.6" for a laptop), and the ruler works out the scale from your screen resolution.

Manual±2%
3

Calibrate with a bank card

Hold any bank card against the outline on screen and move the slider until they match. Bank cards are the same size everywhere: 85.60 × 53.98 mm.

Most Accurate±0.5%
Accuracy

How accurate is the ruler?

How accurate the ruler is depends on how well it knows your screen's pixel density, meaning how many pixels fit in an inch. There are three ways to set it, from most to least accurate:

Bank card (±0.5%): Bank and credit cards are made to one worldwide size, 85.60 × 53.98 mm (ISO/IEC 7810 ID-1). Because every card is exactly the same, matching one on screen gives the most accurate result.

Auto-detect (±1%): The ruler looks up your device's published screen size and resolution. Screens of the same model can differ very slightly, so this is a little less exact. It covers about 130 devices.

Screen size (±2%): You type in your screen size, and the ruler works out the rest from your resolution. Advertised sizes are rounded (a "15.6-inch" screen may really be 15.59 inches), so this is the least exact method. It's a good fallback when you don't have a card.

Reference Sizes

Real-life objects to check your measurements

Use these everyday objects to confirm the ruler is calibrated correctly.

Bank or credit card: 85.60 × 53.98 mm (3.37 × 2.13 in)

A4 paper: 210 × 297 mm (8.27 × 11.69 in)

US Letter paper: 8.5 × 11 in (215.9 × 279.4 mm)

US quarter: 24.26 mm (0.955 in) across

1 euro coin: 23.25 mm (0.915 in) across

AA battery: about 50.5 mm long and 14.5 mm wide

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Measuring guides

FAQ

Frequently asked questions

They mark 16-inch intervals (16, 32, 48, 64 …), the standard spacing between wall studs in US houses, so you can lay out studs without measuring each one.

They mark every 19.2 inches. Five spaces of 19.2 inches make 8 feet, a spacing sometimes used for floor joists and roof trusses.

Count the shortest lines after the last whole inch. Each is 1/16 inch; two are 1/8, four are 1/4 and eight are 1/2. The marker readout here shows the reduced fraction for you.

Only what fits against the screen at once. For longer objects, mark where the screen ends, move the object along and add the lengths, or use a real tape. You can still scroll the on-screen tape to all 25 feet to practise reading it.

It slides by exactly its own thickness, so the reading is right both when you hook it over an edge and when you push it against a wall.