How to Lose a Stone in a Month? How Many Weeks It Takes

At the NHS pace of 1 to 2 lb a week, a stone takes 7 to 14 weeks to lose. A stone is 14 lb, or 6.35 kg. To lose a stone in a month you would need 3.5 lb a week, which is 1.75 to 3.5 times the usual pace. The sums below give the weeks and the daily calories for each pace, then test what your starting weight changes.

How Long Does It Take to Lose a Stone?

Divide 14 lb by your weekly pace. At 1 lb a week that’s 14 weeks, at 2 lb it’s 7 weeks, and the NHS range sits between the two. UK law fixes the units. The Units of Measurement Regulations 1995 set the pound at 0.45359237 kg and the stone at 6.35029318 kg, and the second is exactly 14 times the first.

The table works through four paces. Its last column is the daily gap each pace implies on the old rule of 3,500 kcal per pound. Hall and colleagues found that rule repeated in official advice, the NHS among them, and said it ignores how the body adapts.

Weekly pace	Weeks to lose 14 lb	About how many months	Daily gap at 3,500 kcal per lb
1 lb (0.45 kg)	14	3.2	500 kcal
1.5 lb (0.68 kg)	9.3	2.1	750 kcal
2 lb (0.91 kg)	7	1.6	1,000 kcal
3.5 lb (1.59 kg), a stone in 4 weeks	4	0.9	1,750 kcal

Months here are weeks divided by 4.35. Read the table as the fastest a pace can go, never as a forecast. The same Hall paper explains why the rule overstates loss over months: a smaller body burns less. Weekly loss shrinks as you get lighter, so the last pounds of a stone come slower than the first. Why 3,500 calories per pound misleads goes through the detail.

The NHS page gives its pace twice, as 1 to 2 lb and as 0.5 to 1 kg a week. The two aren’t quite the same, because 2 lb is 0.91 kg. In kilograms a stone takes 12.7 weeks at 0.5 kg a week and 6.4 weeks at 1 kg. The pound figures, 7 to 14, are the ones to plan with, since 1 kg is the looser ceiling.

Real results lag the arithmetic, and one large trial shows it. A Lancet trial of 772 adults in the UK, Germany and Australia compared a commercial weight-loss program with standard care. At 12 months, those who completed the program had lost 6.65 kg on average, and standard-care completers 3.26 kg. Only 61% of the program group completed the 12-month check. Counting everyone assigned, with the last recorded weight carried forward, the averages were 5.06 kg and 2.25 kg. A stone is 6.35 kg. The average completer needed about a year to lose one, and the average person assigned to the program didn’t get there in that year.

How Many Calories a Day Does a Stone Take?

The NHS advises a cut of about 600 kcal a day, and a stone in four weeks would need roughly three times that. It gives 2,000 kcal a day for women and 2,500 for men as the recommended average. The same page says to reduce intake by around 600 kcal a day. Its 12-week plan turns that into 1,400 kcal for most women and 1,900 for most men.

Run 600 kcal through the old rule. Seven days make 4,200 kcal, which is 1.2 lb a week, and 14 lb at 1.2 lb a week takes 11.7 weeks. That’s the NHS plan’s own length, near the slow end of the table. That gap has a name, a calorie deficit, and the NHS calorie deficit advice goes through the NHS figures.

Now the month version. A stone is 14 lb × 3,500 kcal, or 49,000 kcal, and four weeks is 28 days. That’s 1,750 kcal a day. Take the NHS average of 2,000 and you’re left with 250 kcal to eat. Take 2,500 and you have 750. The AHA/ACC/TOS guideline recommends prescribing 1,200 to 1,500 kcal a day for women and 1,500 to 1,800 for men in a weight-loss program. The bottom of each range is the floor used in this article.

So the floor decides. A woman would need maintenance calories above 2,950 (1,200 plus 1,750). A man would need above 3,250 (1,500 plus 1,750). Even then, the plan runs at 3.5 lb a week against a usual 1 to 2.

The floor trims the usual pace as well. Take a woman whose maintenance is the NHS 2,000 kcal. Her floor of 1,200 leaves a gap of 800 kcal a day, which is 5,600 kcal a week or 1.6 lb. At that pace the stone takes 8.75 weeks, so 2 lb a week is closed to her. For a man at 2,500 kcal the floor of 1,500 allows a gap of 1,000, which is exactly 2 lb and exactly 7 weeks.

Your own maintenance estimate comes from the calorie calculator, which takes age, height, weight and activity and keeps its targets at or above the floors above.

There is a slower way to read the same stone. Hall’s model gives a rule of thumb: a permanent cut of 10 kcal a day per pound of weight change eventually removes that pound. For 14 lb that’s 140 kcal a day, with half of the change arriving in about a year and 95% in about three. The model describes an average adult, so 140 is an order of magnitude, not a prescription. Given years instead of weeks, a stone costs very little each day, and that is the real contrast with the month version.

Can You Lose a Stone in a Month if You Weigh More?

Not inside the usual range, at any weight in the table below. The NHS tips page gives one range, 1 to 2 lb, for every adult. What changes with weight is the share. 3.5 lb a week is a bigger bite of a 10 stone body than of a 25 stone one.

A percentage of body weight makes the difference visible. A review of natural bodybuilding contest preparation put weight loss at about 0.5 to 1% of body weight a week to keep muscle. Its subject is athletes dieting for a stage, so I use the 1% as a reference point only, never as a safe limit. The last column applies a rule of my own. It takes the smaller of 1% of body weight and 2 lb a week, so no row goes past the NHS pace.

Starting weight	A stone is this share of it	Weekly loss a 4-week stone needs	Weeks to a stone at the fastest usual pace
9 st (126 lb, 57.2 kg)	11.1%	2.8%	11.1
10 st (140 lb, 63.5 kg)	10.0%	2.5%	10.0
12 st (168 lb, 76.2 kg)	8.3%	2.1%	8.3
14 st (196 lb, 88.9 kg)	7.1%	1.8%	7.1
15 st (210 lb, 95.3 kg)	6.7%	1.7%	7.0
18 st (252 lb, 114.3 kg)	5.6%	1.4%	7.0
25 st (350 lb, 158.8 kg)	4.0%	1.0%	7.0

No row gets under 7 weeks at the usual pace, however much the person weighs. The 2 lb cap takes over from 1% at about 14 stone (91 kg). And a month-long stone only reaches 1% a week at 25 stone, where it’s still 3.5 lb a week. How much weight you can lose in a month gives the usual range by starting weight.

The same weight loss costs different amounts of energy in different bodies. In Hall’s 2008 model, a person who starts with more body fat needs a larger energy deficit for each unit of weight lost. The 3,500 rule approximately matches people who start with more than 30 kg of body fat and overstates the cost for people with less. Two people on the same cut won’t lose the same amount.

Check where the stone lands you. A BMI of 18.5 to 24.9 is the usual range. At 170 cm (5 ft 7 in), 18.5 is 53.5 kg, or 8 st 6 lb. BMI is a rough guide and can’t tell muscle from fat. A goal that takes you below that line is a question for your doctor, and this page isn’t written for it. Anyone who starts inside the range has no weight to lose here.

Why Does the Scale Drop So Fast in Week One?

Part of a fast first week is water. Glycogen is carbohydrate stored in the liver, muscles and fat cells, in a hydrated form with three to four parts water. Using it up therefore lowers the scale without any fat going. Kreitzman and colleagues followed 11 people through 4 days on a very-low-calorie diet, and their paper’s title speaks of illusions of easy weight loss.

The abstract gives no figure for an ordinary deficit, and I won’t make one up. It also lists exaggerated regain after carbohydrate loading among its topics.

So what does the scale tell you? A big drop in week one says little about week five, and 3 lb off in seven days is no reason to multiply by four. Average your morning weights for each week and compare the weeks. That slope is your pace.

Does Weight Lost Quickly Come Back Faster?

The CDC says people who lose about 1 to 2 lb a week are likelier to keep the weight off than quicker losers. One randomized trial disagrees. Purcell and colleagues ran a trial at a Melbourne hospital with adults whose BMI was 30 to 45. It assigned 200 of them to a 12-week or a 36-week program. Both aimed at 15% loss, and 81% in the rapid group lost 12.5% or more in the allotted time, against 50% in the gradual one. After 144 weeks of maintenance, completers in both groups had regained about 71% of what they lost. The authors concluded that the rate of loss didn’t change the share regained.

Read that result narrowly. The adults took part in a hospital trial, and their BMI sat far above where most people asking about a stone begin. “Regained most of it” in both arms also says that keeping weight off is the hard part, at any pace. The NHS still tells people not to lose weight suddenly with diets. The floors above leave no room for a month-long stone anyway. How long you stay in a deficit is its own question, and how long to stay in a calorie deficit covers it.

What Should You Do Today?

Pick the pace you could keep for ten weeks, then divide 14 by it. At 1.5 lb a week the answer is 9.3 weeks. Write the number of weeks down and leave the month out of it.

Next comes your own maintenance. For one week, weigh your food and write down everything you eat, using grams for the foods that carry the most calories. A UK calorie counter app with British food data makes that easier. If your weight stayed flat, that average is your maintenance. It will differ from the NHS 2,000 and 2,500, and it’s the number your plan should use.

Then take the daily gap from the first table and check the result against the floors. If it sits below them, slow the pace. Step on the scale three mornings a week and judge the plan by two-week averages. One reading proves nothing.

If counting calories has started to feel hard to stop, or eating feels out of control, talk to someone: ANAD in the US (1-888-375-7767), Beat in England (0808 801 0677), NEDIC in Canada (1-866-633-4220) or the Butterfly Foundation in Australia (1800 33 4673). If you’re in danger right now, call your local emergency number. Other UK numbers and crisis lines are on our crisis support page.

A stone takes 7 to 14 weeks. Judge it on the two-week average, and treat a stalled fortnight as a reason to check the log first, not to cut further.