How to Use Every Calculator on F*CK Getting Old

Peptide dosing

The Reconstitution Calculator is the one most people come for. Reconstituting a peptide means mixing a freeze-dried vial with bacteriostatic (BAC) water to get an injectable liquid — and figuring out how many units of that liquid equal your intended dose is just arithmetic, but it’s the kind of arithmetic you do not want to get wrong.

Enter your vial size, how much BAC water you added, and your desired dose. It returns the concentration, the units to draw on a standard insulin syringe, and the equivalent volume in mL. Pick a peptide from Quick Select and it will pre-fill typical values from the Peptide Database for you to adjust. If you’re signed in, you can save the result straight to your dosing schedule with one tap.

Metabolic health

Three calculators live under Metabolic Health: a TDEE / Calorie Calculator for estimating maintenance calories, a Protein Calculator for a daily gram target based on your bodyweight and goal, and a Body Fat Estimator using the Navy circumference method — just a tape measure, no calipers or scan required.

Used together, they give you a maintenance calorie number, a protein target to hit while adjusting that number up or down, and a way to check whether the scale moving is actually fat loss or just water.

Strength & training

The One-Rep Max Calculator estimates your 1RM from any working set, so you can program off percentages without maxing out every session. The Heart Rate Zone Calculator gives you Karvonen-method training zones from your age and resting heart rate — useful for keeping Zone 2 cardio actually in Zone 2 instead of accidentally turning it into intervals.

Sleep

The Sleep Debt Calculator turns “I feel tired” into an actual weekly deficit number, and the Sleep Quality Score is a 30-second self-check for last night specifically — latency, wakings, duration, and how you felt getting up. Neither needs a wearable.

Alcohol

A “drink” varies enormously by pour size and ABV. The Standard Drink Calculator converts any pour into US standard drinks (14g pure alcohol), and the Weekly Drinks & Calories tool adds up what that’s actually costing you calorically over a week and checks it against the NIAAA low-risk drinking guideline.

Labs

The Lab Reference Checker lets you punch in a value — testosterone, cholesterol, glucose, and more — and see where it falls against commonly cited reference ranges. Nothing you type is stored anywhere; it runs entirely in your browser and clears on refresh.