Browser-Based Calculation Suite

RepForge Fitness Tools

Practical, scientifically validated calculations for lifters and coaches. Estimate your 1-rep max, dial in your energy balance, build your macro split, and construct your weekly workout schedule.

1RM Estimator Daily Calories & TDEE Macro Calculator BMI Calculator Rest Timer Workout Planner

1. One-Rep Maximum (1RM) Estimator

Estimate your 1RM safely using validated submaximal formulas (Epley, Brzycki, and Lombardi) and generate an instant percentage loading chart.

Estimated One-Rep Maximum (Composite Average)

Formula Breakdown: Epley: -- • Brzycki: -- • Lombardi: --

Training Load Percentages & Rep Targets

Percentage	Target Load	Estimated Reps

Limitation Note: 1RM estimates are mathematical approximations based on normal motor recruitment curves. Individual muscle fiber composition, fatigue state, and exercise familiarity can influence actual 1RM testing. Always use safety pins and spotters.

2. Daily Calorie-Needs Estimator (BMR & TDEE)

Calculate your Basal Metabolic Rate and Total Daily Energy Expenditure using the clinically validated Mifflin-St Jeor formula.

Age (years)

Sex

Weight (lbs)

Height (feet)

Height (inches)

Daily Physical Activity Level

Estimated Total Daily Energy Expenditure (Maintenance TDEE)

Basal Metabolic Rate (BMR): -- (Calories expended at complete rest).

Target Caloric Intakes by Goal

Objective	Target Daily Calories	Expected Biological Rate
Moderate Fat Loss	--	~1.0 lb loss per week (preserves muscle)
Mild Fat Loss	--	~0.5 lb loss per week
Lean Muscle Gain (Hypertrophy)	--	~1.0–2.0 lbs muscle gain/month
Mass Building / Powerlifting	--	High fuel surplus for peak strength

Medical Notice: Calorie estimates are intended solely as starting benchmarks. Track weekly weight averages and adjust energy intake by 100–200 kcal based on real-world trends. This tool does not provide clinical dietary therapy.

3. Macronutrient Calculator

Distribute your target daily calories into optimal gram targets for protein, carbohydrates, and dietary fats.

Target Macronutrient Distribution

Protein: --

Carbohydrates: --

Fat: --

Nutrition Fact: Protein and carbohydrates yield 4 kcal per gram; dietary fat yields 9 kcal per gram. Prioritize high biological value proteins distributed across 3 to 4 daily meals.

4. Body Mass Index (BMI) Calculator

Calculate your BMI score with specialized context regarding muscularity and athletic body composition.

Calculated Body Mass Index

Crucial Caveat for Strength Athletes

BMI is a mathematical quotient of total body mass divided by height squared (kg/m²). It does not differentiate between lean muscle mass and adipose tissue. Well-muscled powerlifters, bodybuilders, and rugby players frequently register in the "Overweight" or "Obese" classifications despite possessing single-digit body fat and exceptional cardiovascular health.

5. Workout Rest Interval Timer

Optimize your neuromuscular recovery between sets with audio alerts synthesized directly in your browser.

01:30

Custom Seconds:

Rest Science Note: Research shows resting 2.5 to 3 minutes on multi-joint lifts (squats, bench, deadlifts) yields superior strength and muscle retention compared to rushing sets at 60 seconds.

6. Weekly Workout Planner & Split Architect

Build, customize, and export a structured 7-day training schedule tailored to your frequency and fitness level.

Select a Proven Training Split Architecture

Planning Note: You can edit any day's focus or exercise list directly in the text boxes above before copying or printing your personalized blueprint.