Taking measurements

1. It’s forbidden to measure precisely on Shabbat as it’s considered Uvda DeChol, a weekday activity.
2. It’s permissible to measure for the purposes of a mitzvah such as measuring Bitul BeShishim, 40 Seah for a Mikveh, or the temperature of someone sick.

Sources

Category	Topic
Mitzvot of Shabbat	Kiddush Levana - Enjoying Shabbat - Fourth meal of Shabbat - Havdalah - Having a meal on Friday - In the Spirit of Shabbat - Kiddush - Lighting Shabbat Candles - Making Early Shabbat - Making one hundred Brachot on Shabbat - Preparing foods on Shabbat - Preparing for Shabbat - Shenayim Mikrah - Kavod Shabbat - Shabbos Davening - Seudat Shabbat - Seudat Shelishit - Lechem Mishneh - Motzei Shabbat - When Does Shabbat Start?
Restrictions of Shabbat	Allowing Carrying Using an Eruv Chatzerot - Animals on Shabbat - Asking a Jew to work on Shabbat - Asking a non-Jew to work on Shabbat (Amirah LeNochri) - Benefiting from a Violation of Shabbat (Maaseh Shabbat) - Books, notebooks, and papers - Brushing Teeth on Shabbat - Building a structure on Shabbat (Boneh) - Carrying on Shabbat - Cleaning the dishes - Cleaning and Folding Garments on Shabbat - Clearing the table - Cooking (Ofeh and Bishul) - Cosmetics on Shabbat - Dancing and clapping on Shabbat - Electricity on Shabbat - Eruv Chatzerot - Eruvin - Games on Shabbat - Getting dressed on Shabbat - Giving birth on Shabbat - Grinding (Tochen) - Handling objects on Shabbat (Muktzeh) - Infants on Shabbat - Introduction to the Modern Eruv - Kneading (Lash) - Mail on Shabbat - Medicine on Shabbat (Refuah on Shabbat) - Melacha That Begins Before Shabbat - Opening bottles and containers (Boneh) - Plants on Shabbat (Zoreah) - Preparing for after Shabbat (Hachana) - Reading on Shabbat (Daber Davar) - Recreation on Shabbat - Sechirut Reshut - Separating mixtures (Borer) - Squeezing fruits (Sechita) - Speaking on Shabbat (Daber Davar) - Taking a cruise over Shabbat - Taking measurements on Shabbat - Techum - Transactions on Shabbat - Transportation on Shabbat - Going to and Staying in the Hospital on Shabbat - Wages on Shabbat (Sachar Shabbat) - Washing one’s body on Shabbat
Melachos	Introduction to Melechet Machshevet - Marbeh Bshiurim - Plowing - Planting - Harvesting - Gathering - Threshing - Winnowing - Separating - Grinding - Sifting - Kneading - Baking and Cooking - Shearing - Laundering - Combing - Dyeing - Spinning - Mounting warp threads - Making two loops - Weaving - Unraveling fabric - Tying - Untying - Gluing, taping, or stapling - Ripping - Trapping - Slaughtering - Skinning - Tanning - Smoothing - Scoring - Cutting precisely - Writing - Erasing - Building - Demolishing - Completing a vessel - Extinguishing a flame - Kindling a fire - Carrying