How Many Calories Do You Burn Doing 1 Sit Up? | Tiny Rep Math

What Counts As One Sit-Up

A clean rep starts from a supine position with knees bent, feet anchored or lightly braced, and the lower back touching the floor. You flex the trunk until shoulders pass the hip line, then return under control. Short crunches are not the same thing. Pace, range, and bracing change the effort level, which is why calorie estimates vary so much from chart to chart.

Calories Burned Doing 1 Sit-Up: By Weight And Pace

The energy cost of movement is commonly estimated with MET values. The Compendium of Physical Activities lists calisthenics like push-ups and sit-ups at 2.8 METs (light effort), 3.8 METs (moderate), and 8.0 METs (vigorous). Using the standard equation, calories per minute ≈ MET × 3.5 × body weight (kg) ÷ 200. Once you have calories per minute, divide by reps per minute to get calories per rep.

Here’s what that means in practice. If you weigh 70 kg and your sit-up pace lands in the moderate band, you burn about 4.65 kcal per minute. At 20 sit-ups per minute, that’s ~0.23 kcal each. Push the pace hard enough to qualify as vigorous and the rate rises to ~9.8 kcal per minute; at 30 sit-ups per minute that’s ~0.33 kcal per rep. Either way, one rep is a tiny slice of energy. The real wins come from total work and weekly consistency, not a single repetition.

Table 1: Calories Per Minute From Sit-Ups By Weight

The ranges below reflect two practical effort bands from the Compendium: moderate (~3.8 MET) and vigorous (~8.0 MET). Values are per minute.

Body Weight	Moderate kcal/min	Vigorous kcal/min
55 kg	3.66	7.70
70 kg	4.65	9.80
85 kg	5.65	11.90

Per-Rep Estimates By Pace

To translate minutes into reps, match the pace to an effort band. A smooth cadence of ~20 sit-ups per minute often feels moderate for practiced movers; ~30 per minute feels vigorous for most people. Using those cadences, you can ballpark calories per rep without a calculator.

• 55 kg: ~0.18 kcal per rep at 20/min; ~0.26 kcal per rep at 30/min.
• 70 kg: ~0.23 kcal per rep at 20/min; ~0.33 kcal per rep at 30/min.
• 85 kg: ~0.28 kcal per rep at 20/min; ~0.40 kcal per rep at 30/min.

Form matters. Shortening the range or using momentum can make a set feel easier without changing the count, which skews any per-rep estimate.

Fat loss still comes from a small, steady calorie deficit over time, not from one exercise alone.

How Many Sit-Ups To Burn 100 Calories

Since one rep burns a fraction of a calorie, the total climbs only when minutes stack up. The table below shows the minutes needed to net ~100 kcal at two effort bands. Reps follow once you pick a cadence.

Body Weight	Minutes To ~100 kcal (Moderate)	Minutes To ~100 kcal (Vigorous)
55 kg	27.3 min	13.0 min
70 kg	21.5 min	10.2 min
85 kg	17.7 min	8.4 min

If you hold 20 sit-ups per minute, a 70-kg person reaches ~100 kcal in about 21–22 minutes, or roughly 420–440 reps. At 30 per minute in the vigorous band, the same person needs around 10 minutes, or ~300 reps.

Sit-Ups Vs Crunches Vs Planks For Calorie Burn

Sit-ups use more hip flexor work than crunches, which can lift the MET band when you move briskly. Crunches keep the range small and stay closer to light or moderate effort for most people. Planks hold tension without reps, so the burn comes from time under load, not movement. A hard front plank might sit near light to moderate on the Compendium scale, yet it taxes the trunk in a different way. For calorie burn alone, movement over minutes wins, which is why brisk walking or step work outpaces slow holds.

Factors That Change Your Numbers

Range Of Motion

Short ranges shave effort. Touching elbows to thighs every rep demands more work than a partial curl where shoulders barely leave the floor.

Anchoring And Surface

Anchored feet shift load to the hip flexors and can make longer sets feel easier, while a sticky mat slows the descent and raises muscular tension. Both tweaks nudge the MET band up or down a notch.

Tempo And Rest

Faster lifting bumps the band toward vigorous; long pauses between sets pull the average back down. If you want a simple rule, pick a pace you can hold with clean reps for at least a minute, and time the work instead of chasing a giant rep number.

Body Weight And Leverage

Heavier bodies burn more energy per minute at the same MET. Arm position changes leverage too: hands by your ears is tougher than arms crossed over the chest, and arms extended overhead is tougher still.

Quick Benchmarks For Common Goals

General Fitness

Two or three sets of 60–90 seconds at a steady pace, three days a week, builds solid trunk endurance without hammering your lower back. Sprinkle planks and loaded carries to round things out.

Sport Prep

Use intervals: 30 seconds on, 15 seconds off, repeated 6–10 times. Keep reps crisp and stop the set if your lower back arches off the floor.

Body Composition

Use sit-ups as a finisher, not the main act. Core sets add a small boost to daily energy use, then the real change happens from steps, rides, and food choices that create a small, steady calorie deficit.

Safe Form And Pace

Set-Up

Bend knees around 90°, feet on the floor, and brace lightly under a couch or against a wall if needed. Cross arms over the chest or touch fingers to temples without pulling the neck.

Execution

Draw ribs toward hips as you curl up until shoulders pass the hip line, then lower under control. Keep the movement smooth; avoid yanking with the hip flexors.

Breathing

Exhale during the ascent and inhale on the way down. A steady rhythm helps you hold pace and protect the lower back.

Mini Calculator: Do Your Own Math

Use this three-step method to tailor the estimate to your body and pace:

1. Pick an effort band: light (2.8 MET), moderate (3.8 MET), or vigorous (8.0 MET).
2. Compute calories per minute: MET × 3.5 × your weight (kg) ÷ 200.
3. Divide by your cadence (sit-ups per minute) to get calories per rep.

Worked sample: 70 kg at moderate pace → 3.8 × 3.5 × 70 ÷ 200 ≈ 4.65 kcal per minute. At 20 sit-ups per minute, that’s ~0.23 kcal per rep; 100 reps cost ~23 kcal.

Common Mistakes That Skew The Math

• Counting Crunches As Sit-Ups. Crunches use a shorter range and usually sit in a lower MET band, so the per-rep burn is smaller.
• Letting Momentum Do The Work. Throwing the arms or bouncing off the floor lowers muscular demand while the rep counter still climbs.
• Racing Past Clean Form. A breathless sprint often turns into half reps. A steady cadence with real range gives you numbers you can trust.
• Using Only Rep Goals. Time your work too. Minutes are what the formulas use, and minutes make your log easy to compare week to week.

Two More Quick Samples

At 55 kg and 30 per minute, calories per minute land near 7.7, so a single rep costs 0.26 kcal. At 85 kg and 20 per minute, calories per minute sit near 5.65, so one rep costs 0.28 kcal. The pattern is simple: more body mass or more effort raises the total number, yet it stays mostly small per rep.

Where Sit-Ups Fit In A Weight Plan

Sit-ups build trunk endurance and teach you to brace. As a tool for fat loss, they’re a minor player because total energy cost is small per minute compared with running or stepping. Pair core work with walking, cycling, or intervals you enjoy, and keep protein steady at meals. The steady routine reduces the noise in daily energy balance, far more than chasing another set of abs work.

Smart Ways To Program Them

• Use time blocks, not just rep goals. Two or three blocks of 60–90 seconds with calm breathing keeps quality high.
• Mix patterns. Rotate sit-ups with planks, dead bugs, and carries to spread the load on the spine.
• Stop before your form slips. If the last few reps look sloppy, rest and reset.

Bottom Line

One sit-up costs a fraction of a calorie. The exact number depends on your weight, effort, and cadence. Use the tables and the mini calculator to size your sessions, then let weekly movement and food choices do the heavy lifting. Want an easy next step? Try our benefits of exercise.