ExactSize Tools
Find the size of the thing in your hand.
Free online size checkers and digital gauges. Calibrate your screen once, then compare real objects to standard physical sizes.
Free · No account · Runs in your browser
What are you trying to identify?
- ElectronicsLaptop Charger TipFind the physical dimensions of an unknown round DC power connector.
- Yarn & NeedlecraftCrochet HookIdentify an unmarked crochet hook by shaft diameter.
- Yarn & NeedlecraftKnitting NeedleIdentify an unmarked knitting needle shaft.
- Workshop & HardwareDrill BitFind the closest metric or fractional drill size.
- Workshop & HardwareScrewFind screw diameter and approximate length.
- Workshop & HardwareBoltMeasure bolt diameter and approximate length.
- Workshop & HardwareWasherCompare washer inner and outer diameters.
- Jewelry & CraftsBeadCompare beads to actual-size diameter circles.
See the full tools directory or Workshop & Hardware tools.
How it works
Step 1
Calibrate your screen
Match a credit card outline once. Every tool shares the same scale.
Step 2
Compare the object
Hold the real item against on-screen gauges at approximately physical size.
Step 3
Find the closest standard size
See the nearest verified standard and nearby alternatives.
Closest standard size. Calibrate your display for best accuracy. Verify critical measurements using appropriate physical measuring equipment. Read the full method.
What is ExactSize Tools?
ExactSize Tools is a collection of online size checkers: browser-based digital gauges that help you identify unmarked physical objects. You calibrate the screen once, then hold a real charger tip, crochet hook, knitting needle, drill bit, screw, bolt, washer, or bead against shapes drawn at approximately real size.
The product is intentionally narrow. There is no camera measurement, no account, and no claim of lab precision. When diameter alone cannot answer a question (thread pitch, charger voltage, proprietary tip shapes), the tools say so. Learn more on the about page.
How does an online size checker work?
Your display has a fixed pixel density. Calibration finds a pixels-per-millimeter scale (credit card matching is recommended) and stores it in this browser. Each gauge then draws known diameters and lengths using that scale so on-screen size matches the real world as closely as the display allows.
You compare by eye: align the object with the reference, then read the closest verified standard plus nearby alternatives when sizes are close. That workflow is the same across every tool. Details live on how it works and calibration.
What can you measure?
Only the objects with live tools today. Each link opens a dedicated checker with its own size chart where one exists:
- Laptop charger tip size checker for round DC barrel OD × ID
- Crochet hook size checker with a metric size chart
- Knitting needle size chart and shaft checker
- Drill bit size checker for metric and fractional bits
- Screw size checker and bolt size checker for major diameter and length
- Washer size checker for inner and outer diameter
- Bead size chart at actual size
Why a digital gauge instead of a normal ruler?
A ruler answers “how long is this?” in generic units. A digital gauge answers “which standard size is this?” by placing the object next to the same diameters used in the industry chart for that product.
That matters when markings are worn off, when you are choosing between close sizes (4 mm vs 6 mm beads, M5 vs #10 shafts), or when you need OD and ID together on a charger tip. You still may want calipers for critical work; these tools are built for quick closest-standard checks without buying another gauge for every hobby.
How accurate is ExactSize Tools?
Accuracy tracks your calibration. Credit card matching is recommended because ISO/IEC 7810 ID-1 cards have a known physical size. Diagonal entry and automatic guesses are available when a card is not handy, but they are usually less reliable.
Results report the closest verified standard and nearby alternatives, not false millimeter precision. Screen bezels, thick cases, and viewing angle can still throw comparison off. For safety-critical, structural, or electrical decisions, confirm with appropriate physical measuring equipment.
Built for closest-standard identification
Calibrate once, share everywhere
One display scale powers every gauge. Credit-card matching is recommended; nothing is scanned or uploaded.
Closest standard, not fake precision
Results show the nearest verified standard and nearby alternatives. Critical work still needs physical measuring tools.
Runs in your browser
Calibration stays in local storage on this device. No account required for measurement tools.
Honest limits
Thread pitch, voltage, and proprietary tip shapes are not invented from diameter alone. Warnings stay visible where they matter.
Read more in How it works and About.
Frequently asked questions
What is ExactSize Tools?
ExactSize Tools is a free set of online size checkers and digital gauges. After you calibrate your display, each tool draws verified object sizes at approximately real physical size so you can identify unmarked items by comparison.
How does an online size checker work?
You calibrate the screen once (credit card recommended), open a tool for the object type you have, then hold the real item next to the on-screen gauge. The page reports the closest verified standard and nearby alternatives—not a laboratory measurement.
Do I need to calibrate every time?
Calibration is stored locally on this device. Re-check if you change displays, zoom, or browsers, or if results look off. Start at Calibrate when in doubt.
How accurate is screen comparison?
Accuracy depends on calibration quality and careful alignment. Results are closest-standard matches. Thick cases, bezels, and viewing angle can throw comparison off. Verify critical sizes with physical measuring equipment.
Does this work on phones and tablets?
Yes. Phones and tablets work after calibration. Smaller screens and cases can make alignment harder—take extra care, or use a larger calibrated display when precision matters.
Do I need an account or app?
No. ExactSize Tools runs in your browser. Calibration stays in local storage on this device. Nothing is uploaded for measurement.