How Does Orangetheory Calculate Heart Rate Zones

OTF Heart Rate Zone Estimator

Estimate your Max HR and Splat Point zones based on the Tanaka formula (standard calibration).

Tanaka (208 – 0.7 × Age) – Modern Standard Fox (220 – Age) – Old Standard Gulati (206 – 0.88 × Age) – Female Specific

Estimated Max Heart Rate

0 BPM

Zone 1: Grey (Very Light) 50-60% Max HR

— BPM

Zone 2: Blue (Warm Up) 61-70% Max HR

— BPM

Zone 3: Green (Base Pace) 71-83% Max HR

— BPM

Zone 4: Orange (Push Pace) 84-91% Max HR • SPLAT POINTS START HERE

— BPM

Zone 5: Red (All Out) 92-100% Max HR

— BPM

How Does Orangetheory Calculate Heart Rate Zones?

Orangetheory Fitness (OTF) bases its entire workout methodology on heart rate-based interval training. The goal is to spend specific amounts of time in different "zones" to stimulate metabolism, increase energy, and achieve the "Orange Effect" (excess post-exercise oxygen consumption, or EPOC). But how exactly are these numbers derived?

The Evolution of the Max Heart Rate Formula

Your heart rate zones are calculated as a percentage of your maximum heart rate (Max HR). Historically, OTF and many fitness trackers used the standard Fox formula: 220 minus your age. While simple, this formula has been criticized for lacking accuracy across different demographics.

More recently, OTF transitioned to the Tanaka Formula (also known as the "New Standard"), which is generally considered more accurate for healthy adults. The calculator above uses this as the default method:

• Tanaka Formula: 208 – (0.7 × Age)
• Gulati Formula: 206 – (0.88 × Age) (Specifically designed for women)

Note: Current Orangetheory members may see slightly different numbers in the studio because OTF now uses a proprietary algorithm that adjusts your Max HR based on your last 20 workouts. However, for new members or those estimating their zones, the Tanaka formula is the closest standard approximation.

Understanding the 5 Zones and Splat Points

Once your Max HR is established, it is divided into five color-coded zones based on percentage of effort:

1. Grey Zone (50-60%)

This is your comfortable, resting activity level. You are in this zone before class starts or during transitions.

2. Blue Zone (61-70%)

The "Warm Up" zone. Your breathing gets heavier, but you can still hold a conversation. This prepares your body for higher intensity.

3. Green Zone (71-83%)

Known as "Base Pace." This is a challenging but doable pace. It is aerobic exercise where you burn fat and carbohydrates evenly. You should aim to spend 25-30 minutes of the class here.

4. Orange Zone (84-91%) – The Splat Points

This is the "Push Pace." This is an uncomfortable zone where you utilize anaerobic metabolism. For every minute you spend in the Orange (or Red) zone, you earn 1 Splat Point. The goal of every class is to achieve at least 12 Splat Points to maximize the afterburn effect.

5. Red Zone (92-100%)

The "All Out" effort. You should empty the tank here. This zone is usually held for short bursts (30-60 seconds) and is not meant to be sustained for long periods.

Why does the formula matter?

If your estimated Max HR is too high, you might struggle to ever reach the Orange zone (getting 0 Splat Points) despite working extremely hard. Conversely, if the estimate is too low, you might accumulate 40+ Splat Points without feeling breathless. This calculator helps you verify if the studio's calibration matches standard physiological science.

function calculateOTFZones() { // 1. Get Inputs var ageInput = document.getElementById('otf_age'); var formulaSelect = document.getElementById('otf_formula'); var age = parseFloat(ageInput.value); var formula = formulaSelect.value; var maxHR = 0; // 2. Validate Input if (isNaN(age) || age 120) { alert("Please enter a valid age between 10 and 120."); return; } // 3. Calculate Max Heart Rate based on selected formula if (formula === 'fox') { // Fox Formula: 220 – Age maxHR = 220 – age; } else if (formula === 'gulati') { // Gulati Formula: 206 – (0.88 * Age) maxHR = 206 – (0.88 * age); } else { // Tanaka Formula (Default): 208 – (0.7 * Age) maxHR = 208 – (0.7 * age); } // Round Max HR maxHR = Math.round(maxHR); // 4. Calculate Zones // Zone 1: 50-60% var z1_min = Math.round(maxHR * 0.50); var z1_max = Math.round(maxHR * 0.60); // Zone 2: 61-70% var z2_min = Math.round(maxHR * 0.61); var z2_max = Math.round(maxHR * 0.70); // Zone 3: 71-83% var z3_min = Math.round(maxHR * 0.71); var z3_max = Math.round(maxHR * 0.83); // Zone 4: 84-91% var z4_min = Math.round(maxHR * 0.84); var z4_max = Math.round(maxHR * 0.91); // Zone 5: 92-100% var z5_min = Math.round(maxHR * 0.92); var z5_max = maxHR; // 5. Update UI document.getElementById('result_max_hr').innerText = maxHR; document.getElementById('zone1_range').innerText = z1_min + " – " + z1_max; document.getElementById('zone2_range').innerText = z2_min + " – " + z2_max; document.getElementById('zone3_range').innerText = z3_min + " – " + z3_max; document.getElementById('zone4_range').innerText = z4_min + " – " + z4_max; document.getElementById('zone5_range').innerText = z5_min + " – " + z5_max; // Show results div document.getElementById('otf_results').style.display = 'block'; }