A tub with 30 servings lasts 10 weeks if you use three labelled servings a week. The same tub lasts six weeks at five servings a week. Start with the amount you actually use and the days you use it.
Read two numbers on the label
- Serving size in grams. Use the weight of powder listed for one serving. The grams of protein per serving are a separate number.
- Servings per container. If the label gives only the net weight and serving size, divide the net powder weight by the serving size. A 990 g tub with 33 g servings works out to 30 servings.
For a broader walkthrough of what these numbers mean, see our guide to portions and nutrition labels.
Calculate how many weeks your tub will cover
Weeks of use = servings in the tub ÷ servings you actually use per week. These schedules are examples for the calculation. Use the serving size on your own label and record the days you already use the product.
| Weekly use | Calculation | Estimated duration |
|---|---|---|
| Three servings per week | 30 ÷ 3 | 10 weeks |
| Five servings per week | 30 ÷ 5 | 6 weeks |
| Four servings one week, two the next | 30 ÷ 3, using the two-week average | About 10 weeks |
Turn that estimate into a shopping decision
Suppose you want to budget for the next four weeks and use three servings per week. Your plan calls for 12 servings. If your open tub already covers those 12, put the next purchase on a later shopping list. If there are only eight left, the difference is four.
To estimate what remains in an open tub, subtract the portions already used from the labelled total. If you share the tub with someone else, count both people’s use. For a schedule that changes regularly, record two ordinary weeks and use their average.
If you have yet to map out which days you eat at home, take a packed meal or use what you already have, use Fat Killer’s seven-day meal planner for training and rest days to mark your actual routine. Then bring your weekly number back to this calculation.