How to Calculate Your 1RM From Reps (Chart + Examples)

You don't have to max out to know your max. Any hard set of 2–10 reps already tells you roughly what you could lift once.

The short answer: multiply the weight by (1 + reps ÷ 30). That's the Epley formula: 1RM = weight × (1 + reps ÷ 30). A bench of 225 lb × 5 reps gives 225 × 1.167 = 262.5 lb (119 kg). In kg, 100 kg × 5 gives about 117 kg. It works best for sets of about 3–10 reps taken close to failure.

This guide gives you the formulas, a reps-to-max chart, worked examples in lb and kg, the "how many reps of 225 equal a 315 bench" answer, and the mistakes that make the estimate wrong. Every number here was calculated with a script, not by hand.

The 1RM formulas (Epley, Brzycki, Lombardi)

There are a few common formulas. They all do the same job: turn "weight × reps" into an estimated one-rep max.

They land within about 12 lb (5 kg) of each other at 5 reps, and agree almost exactly at 10 reps (135 × 10 is 180 lb with both Epley and Brzycki). The gap grows at high reps, which is one reason high-rep estimates are less trustworthy (more on that below).

Which one should you use? Pick one and stick with it. Your estimated max is most useful as a trend: if it goes up week to week, you're getting stronger, whichever formula you use. Switching formulas halfway makes your progress look like it jumped or dropped when nothing changed. Liftly uses Epley, and so does every example in this guide unless it says otherwise.

Reps-to-max chart (percent of 1RM)

This is the same math as a table. Find how many reps you did, then divide the weight by the percentage (or multiply by the multiplier) to get your estimated max.

One quirk: taken literally, Epley says a single rep is 96.8% of your max (it multiplies a 1-rep set by 1.033). A true single is your max, so the chart shows 100%. Apps that apply Epley to every set, Liftly included, will show a logged single about 3% above the weight on the bar (225 × 1 shows as about 232 lb).

How to calculate 1RM from 3, 5, 8 or 10 reps

Same formula, different multiplier. Here are worked examples in lb and kg:

From a 5RM: multiply by 1.167. From a 3RM: multiply by 1.1. From an 8RM: multiply by 1.267. From 10 reps: multiply by 1.333 (or divide by 0.75). Those four cover most of what people search for.

The method is the same for the bench, squat, deadlift, overhead press or a dumbbell press. For dumbbells, use the weight of one dumbbell and you get a one-dumbbell max.

How many reps of 225 to bench 315?

This works in reverse too. To find how many reps of a weight equal a target max, use reps = 30 × (target ÷ weight − 1) and round up.

So 225 for 12 reps is roughly a 315 bench by both formulas, and 315 for 9 reps is roughly a 405 deadlift. Look at the 405 row, though: Epley says 24 reps of 225, Brzycki says 17. When formulas disagree by 7 reps, neither is telling you much. Past about 12 reps, the set is testing endurance as much as strength, so treat these as rough guesses. (That's why the NFL Combine's 225 test is a max-reps test, not a 1RM test.) If you want to know what a 225 bench means for your bodyweight, see is 225 bench good.

Working backwards: what to lift for 5 or 8 reps

If you know your max, flip the formula to pick working weights: weight = max ÷ (1 + reps ÷ 30). Here it is for a 225 lb and a 100 kg max, rounded down to a weight you can load (5 lb or 2.5 kg jumps):

These are all-out sets. For several sets, like 5×5, start below your five-rep number, because the first set's fatigue carries into the next four. You can't do five sets of five at a weight you can only lift five times once.

Why your estimated max can be wrong

The formula is only as good as the set you feed it. The common ways it goes wrong:

1. The set wasn't hard. The formulas assume you went close to failure. If you stopped 185 × 6 with two reps left, the formula sees 222 lb when your real 8-rep effort would give 234 lb. A simple fix: add the reps you had left. If you rate effort with RIR (reps in reserve), 6 reps at 2 RIR counts as 8.
2. Too many reps. Rule of thumb: the estimate is most reliable between about 3 and 10 reps. Above 12 it usually overstates your max, and the formulas start to disagree.
3. People and lifts differ. Two lifters with the same max won't always get the same reps at the same weight, and a formula can fit one lift better than another. Treat it as an estimate for you, not a law.
4. Form changed. A bench with a pause, a squat to full depth and a deadlift without straps aren't the same lift as their sloppier versions. Compare like with like.

The fix for all four is the same: use the estimate as a trend, not a single verdict. One set can mislead you. The direction over 8 weeks of sets rarely does.

Should you test a true 1RM instead?

You can, but most lifters don't need to. A real max needs a full warm-up, a spotter or safety bars, and a fresh day, and it tells you about one day. An estimated max from your normal sets costs nothing and updates every workout. That's the idea behind tracking progressive overload with an estimated 1RM: if 225 × 5 turns into 225 × 7 over a month, your estimated max went from 262.5 to 277.5 lb without a single max attempt.

Test a true max when you actually need one: a powerlifting meet, a program that's based on a tested max, or because you want to see it on the bar.

Tracking your 1RM in Liftly

Doing this math with a calculator after every workout gets old. In Liftly you just log the set:

• Estimated 1RM for every set. Liftly uses Epley on each set you log and shows the "Estimated 1RM progression" chart on the Insights tab, so you see the trend, not one number.
• PRs flagged. When a set beats your best, Liftly pops up a PR as you log it.
• Last time pre-filled. Opening an exercise fills in last session's weight, with last time's reps as grey hints, so you know exactly what to beat.
• Ranks (Liftly Pro). Your estimated max divided by your bodyweight becomes a rank for each muscle, from Newbie to GOAT. For example, a 180 lb lifter who benches 225 × 5 has an estimated max of 262.5 lb, or 1.45× bodyweight: Pro I for chest if the bench is their only chest lift. The next tier, Pro II, needs an estimated max of about 265 lb, so 225 × 6 or 230 × 5 gets there. How Liftly's gym ranks work explains the full system.

Logging is free. Ranks, next-workout weight targets and advanced analytics are part of Liftly Pro, which has a free trial. If you'd rather log on paper first, our free workout log template has an Epley column built in.

FAQ

How do I calculate my 1RM from 5 reps?

Multiply the weight by 1.167 (that's 1 + 5 ÷ 30, the Epley formula). For example, 225 lb × 5 gives 262.5 lb, and 100 kg × 5 gives about 117 kg. Brzycki's formula (× 1.125 at 5 reps) gives a slightly lower number: about 253 lb and 112.5 kg.

What is the most accurate 1RM formula?

There isn't one winner for everyone. Epley and Brzycki give the same answer at 10 reps and stay close below that; they drift apart at high reps. Accuracy depends more on the set (close to failure, 3–10 reps, good form) than on the formula. Pick one and use it every time so your numbers stay comparable.

How many reps of 225 equal a 315 bench?

About 12. Epley says 225 × 12 = 315 lb exactly, and Brzycki rounds up to 12 as well. Since 12 reps is at the edge of where the formulas are reliable, someone who gets 12 reps might max a little under or over 315.

How many reps of 315 to deadlift 405?

About 9 reps by both the Epley and Brzycki formulas (Epley gives 8.6, which rounds up to 9). Deadlift reps with good form get harder fast, so a clean 9 is a better sign than a grindy 9 with a rounded back.

How do I calculate 1RM in kg?

Exactly the same way: the formulas don't care about units. 80 kg × 8 is 80 × 1.267 = about 101 kg with Epley. To switch units, 1 kg = 2.2046 lb.

Is an estimated 1RM the same as a real max?

No. It's an estimate of what you could lift once on a good day, and your real max can be above or below it. Its real value is the trend over weeks, which is what an app like Liftly charts for you.