UFitnessSG Strength Planning Tool

Estimated One Rep Max Calculator

Estimate your one-repetition maximum from a controlled submaximal lift. This tool is designed for education, strength planning, and safer training load selection — not for encouraging unsupervised maximum lifting attempts.

Safety-first note: This calculator should be used only after proper warm-up sets and a controlled working set. Beginners, seniors, individuals with medical conditions, or anyone unsure about heavy resistance training should seek guidance from a qualified exercise professional.

Calculate Your Estimated 1RM

Enter the weight lifted and the number of good-quality repetitions completed during your controlled submaximal working set.

Estimated One Rep Max

0 kg

Training Load	Estimated Weight	Suggested Use

When Should You Use This Calculator?

The calculator is used after warm-up sets, when you have completed a challenging but controlled working set with good form.

Readiness Check Ensure you are pain-free, familiar with the exercise technique, and medically suitable for higher-intensity resistance training.

Warm-Up Sets Perform light to moderate warm-up sets first. These sets prepare the body and should not be entered into the calculator.

Submaximal Working Set Complete a controlled set, preferably around 3 to 6 good repetitions. This is the set used for calculation.

Estimate and Plan Use the result to guide training loads, not to prove your maximum strength or attempt unsafe lifting.

Understanding the Formula

This calculator uses the Epley formula, a commonly used method to estimate one-repetition maximum from a submaximal lift.

Estimated 1RM = Weight × (1 + Reps ÷ 30)
Example: If you lift 80kg for 5 good reps, your estimated 1RM is approximately 93.3kg.

Best Range 3 to 6 controlled repetitions usually provide a more useful estimate for strength planning.

Acceptable Range 7 to 10 repetitions may still be used, but the estimate may become less precise.

Use With Care Higher repetitions, poor form, fatigue, or rushed testing can affect the accuracy of the result.

Safety and Professional Guidance

This tool is developed with reference to ACSM exercise testing and resistance-training principles. It is not an ACSM-approved tool and does not replace individual assessment by a qualified exercise professional.

Do not use this calculator if you are experiencing chest pain, dizziness, unusual shortness of breath, joint pain, recent injury, loss of control during movement, or if you are unsure whether heavy resistance training is suitable for you.

Stop immediately if you feel pain, dizziness, chest discomfort, unusual breathlessness, or any symptom that does not feel normal.

Build Strength With Clarity, Not Guesswork

Follow UFitnessSG for practical strength, movement, and active ageing education. Use free tools like this to understand your body better and make safer training decisions.

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