One Rep Max Calculator

Estimate your one-rep max (1RM) from a lighter set and get a full percentage-of-1RM training table. Free, instant, no signup.

Formula: 1RM = weight × (1 + reps ÷ 30) (Epley)

How to use the One Rep Max Calculator

  1. Enter your values. Fill in the fields with your numbers.
  2. Calculate. Press Calculate to run the one rep max calculator.
  3. Use the result. Copy the result or try a related tool next.

Why use our One Rep Max Calculator

Instant results. Enter your figures and the one rep max calculator returns an answer in seconds.
Free & private. Runs in your browser — no signup, and nothing is sent to a server.
Accurate. Uses standard formulas so you can rely on the numbers.

Free to use — premium coming soon

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About the One Rep Max Calculator

The One Rep Max Calculator estimates the heaviest weight you could lift one time for a given exercise, without you having to actually attempt that risky maximal single. You enter the weight you lifted and how many clean reps you completed, and the tool projects your 1RM from a set you can already perform safely. It is built for the squat, bench press, deadlift, overhead press and similar barbell or dumbbell lifts, where knowing your true ceiling lets you program every other workout as a percentage of it.

Reach for this calculator when you are planning a strength block, comparing progress month to month, or setting target loads for a program written in percentages. Instead of grinding out a nervous max attempt, you do a confident set of, say, 5 reps and let the math do the rest. It also helps you avoid the opposite mistake of always lifting too light: once you know your estimated max, you can deliberately put working sets in the 70 to 90 percent range that actually drives adaptation for size or strength.

Under the hood the tool applies validated submaximal formulas. The Epley equation is 1RM = weight x (1 + reps / 30); the Brzycki equation is 1RM = weight x 36 / (37 - reps). Both return the same number at exactly 10 reps and diverge slightly elsewhere, so many calculators average several formulas. Accuracy is highest in the 2 to 10 rep range, where estimates fall within roughly 5 percent; push past 10 or 12 reps and the projection drifts because muscular endurance, not raw strength, starts driving the set.

Treat the output as a well-grounded estimate, not a guaranteed number on the bar. Form breakdown, fatigue, grip, and exercise choice all shift the real value, so re-test with a fresh set every few weeks rather than trusting an old figure. The calculation runs entirely in your browser: your weights, reps and results are never uploaded or stored on a server, so your training log stays private to you. Nothing here is medical advice; if you are new to maximal training, work with a coach and use a spotter.

Frequently asked questions

Which formula does this 1RM calculator use?

It is based on the widely used Epley formula, 1RM = weight x (1 + reps / 30), and cross-checks against Brzycki, 1RM = weight x 36 / (37 - reps). These are the two most established submaximal estimation methods and agree exactly at 10 reps.

How many reps should I use for the most accurate estimate?

Use a hard but clean set of 2 to 10 reps. In that window the estimate is typically within about 5 percent of your true max; above 10 to 12 reps endurance starts to skew the result and accuracy drops sharply.

Is the calculated number my real one rep max?

No, it is an estimate, not a tested max. Your actual 1RM depends on form, fatigue, grip and the specific lift, so the figure may differ by 5 to 10 percent or more. Use it to plan loads, then verify periodically with a real attempt if you choose.

How do I turn my 1RM into training weights?

Multiply your estimated 1RM by a target percentage: roughly 50 to 60 percent for speed and power, 70 to 80 percent for muscle size in the 8 to 12 rep range, and 85 to 95 percent for pure strength in low reps. For example, 80 percent of a 200 lb 1RM is 160 lb.

Do I need to do a true max lift to use this?

No, and that is the point. The calculator exists so you can avoid an intimidating single-rep attempt and instead estimate your max from a safer submaximal set you already complete with good technique.

From our blog

How to Evaluate a Pay Raise: From Percentage to Real Take-Home

By the Super Simple Digital Tools Team · Updated June 2026

When a raise lands in your inbox it usually arrives as a single number, either a percentage or a new salary figure, and that lone number hides a lot. The first move is to translate it into the same units you actually spend money in. A 3% bump on $65,000 sounds modest, but it's $1,950 a year, about $162 a month, and roughly $0.94 more an hour. Seeing all four views at once is the difference between a vague 'okay' and a real decision, and it's exactly what a pay raise calculator is built to surface in a single step.

The second step is benchmarking. A raise only means something relative to two things: inflation and the market. With cost-of-living adjustments running around 2 to 3 percent and the 2026 Social Security COLA set at 2.8%, a raise below that range is effectively a pay cut in buying power. Average employer salary budgets for 2026 sit near 3.5%, so anything meaningfully under that may signal you're being undervalued. Use the calculator to express your raise as a clean percentage, then hold it up against these reference points before you celebrate or negotiate.

Third, separate gross from net. The headline number on your offer letter is pre-tax, and a raise can quietly push part of your income into a higher marginal bracket. Only the dollars above the threshold are taxed at the higher rate, so a raise never reduces your overall take-home, but it does mean you keep less of each new dollar than of your base pay. Federal income tax plus Social Security and Medicare alone trim 7.65% off the top before income tax even applies, so plan around the net figure, not the gross.

Fourth, think in compounding terms for anything long-running. Raises stack on top of each other, so the base you start from matters more than any single year's percentage. Two years of 4% beats one year of 5% followed by a flat year, because the second 4% is calculated on an already-higher number. If you're weighing a job change, calculate the new annual figure and project a couple of years forward; a higher starting salary often outruns a slightly bigger one-time percentage at your current employer.

Finally, use the numbers to negotiate concretely. Walking into a review saying 'I'd like more' is weak; saying 'a 6% increase would bring me to $68,900, which aligns with market data for this role' is specific and hard to dismiss. Run the figures first so you can name an exact target salary, an exact percentage, and what it means per paycheck. The calculator removes the mental math, leaving you free to focus on the case you're making rather than the arithmetic behind it.

  • Enter both your current and proposed salary to get the exact raise percentage, then compare it directly against the 2.8% COLA and the ~3.5% average employer budget for 2026.
  • Always read the per-paycheck number, not just the annual one. A $1,800 raise feels large until you see it's about $69 per biweekly check before tax.
  • Estimate your net by keeping roughly 65 to 80 percent of the gross raise, since FICA alone takes 7.65% before income tax is applied.
  • When comparing a salaried offer to an hourly one, divide annual pay by 2,080 to get a true apples-to-apples hourly rate before deciding.

Read the full guide →

Tool by the Super Simple Digital Tools Team. Reviewed by our editorial team. Free to use, no signup required.

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