Size Calculator – Ring, Hat, Font & Chest Size Converter Online

  • Adam
  • November 22, 2025

Free size calculator to convert ring size inches to US size, hat size from circumference, font size to inches, and chest measurements. Instant size conversions with charts.

Size Calculator

Convert Ring, Hat, Font & Chest Sizes Instantly

Universal Size Converter

Ring Size Conversion Guide

Ring size is typically measured by the inner diameter or circumference of the ring. US ring sizes follow a standardized system where each size increases by approximately 0.032 inches in diameter.

Ring Size Formula

Circumference Formula:

C = πd

US Size Approximation:

Size ≈ (d - 0.458) / 0.032

Where d = diameter in inches, C = circumference, π ≈ 3.14159

Hat Size Conversion Guide

Hat size is determined by measuring the circumference of your head about 1 inch above your eyebrows. The measurement in inches is then converted to a hat size using a standard formula.

Hat Size Formula

US Hat Size Formula:

Hat Size = (Circumference - 10) / 2

Example: 22 inches head circumference = (22-10)/2 = size 7

Font Size Conversion Guide

Font size in typography is measured in points (pt), where 1 point equals exactly 1/72 of an inch. This standard was established in desktop publishing and remains universal across digital and print media.

Font Size Formulas

Points to Inches:

Inches = Points / 72

Inches to Points:

Points = Inches × 72

Quick Reference Charts

Ring Size Chart

US Size Diameter (in)
50.618"
60.650"
70.706"
80.738"
90.770"

Hat Size Chart

Circumference Hat Size
21.5"6 7/8
22"7
22.5"7 1/8
23"7 1/4
23.5"7 3/8

Frequently Asked Questions

How do I convert inches to ring size?

To convert inches to ring size, measure the inner diameter of your ring in inches and use a conversion chart or formula. For example, 0.706 inches equals US size 7. The relationship is approximately: Size ≈ (diameter - 0.458) / 0.032. Each US ring size increases by about 0.032 inches in diameter. Use our calculator for instant conversion with accurate results.

How to measure hat size in inches?

Measure hat size by wrapping a flexible measuring tape around your head approximately 1 inch above your eyebrows and ears, where a hat would naturally sit. The circumference in inches determines your hat size using the formula: Hat Size = (Circumference - 10) / 2. For example, 22 inches circumference = size 7, 22.5 inches = size 7 1/8.

How to convert font size to inches?

Convert font size (points) to inches using the formula: Height in inches = Points / 72. This is because 1 point = 1/72 inch in typography. For example, 72pt = 1 inch, 36pt = 0.5 inches, 12pt = 0.167 inches. This standard applies to both print and digital media. The conversion is exact and universally recognized in graphic design.

How to convert chest size from cm to inches?

Convert chest size from centimeters to inches by dividing by 2.54: Inches = cm / 2.54. For example, 100 cm = 39.37 inches. This is useful for international clothing sizes: 90-95 cm (35-37") = Small, 95-100 cm (37-39") = Medium, 100-105 cm (39-41") = Large, 105-110 cm (41-43") = X-Large. Always measure around the fullest part of your chest.

What is US ring size 7 in inches?

US ring size 7 has an inner diameter of 0.706 inches (17.3 mm) and a circumference of 2.22 inches (56.5 mm). This is one of the most common ring sizes for women in the United States. To find your size, measure the inside diameter of a ring that fits you well and compare it to a ring size chart or use our calculator.

Disclaimer: This size calculator provides conversions based on standard sizing charts and formulas. Ring sizes follow US standard measurements; actual sizes may vary slightly by manufacturer. Hat sizes are based on standard US sizing. Font size conversions assume standard print resolution (72 points per inch). Chest measurements should be taken at the fullest part. For critical applications (jewelry purchases, custom clothing), always verify measurements with a professional or use official sizing tools.

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