Beauty Products Calculator — How Long Will It Last?
Enter the total amount in the bottle and how much you use each day to find out exactly how many days, weeks and months the product will last — plus the daily cost if you add the price.
Unit of measurement
ml
ml/day
Based on the total amount divided by your daily usage
- 1
Product amount
150 - 2
Days until empty
150 ÷ 1.5 = 100
How does this calculator work?
Divide total product volume (ml or g) by daily usage to get how many days it lasts. Divide the price by that number for cost per day. A 150 ml bottle used at 1.5 ml per day lasts 100 days; at £25 that is £0.25 per day.
Formula
How this is calculated
The calculator divides the total amount of product (in millilitres, grams or fluid ounces) by your average daily usage to give the number of days before the product runs out. Weeks are calculated by dividing days by 7; months use an average calendar month of 30.44 days.
If you add a price, the calculator derives the cost per day (price ÷ days) and the cost per unit of measurement. This lets you compare two products with different sizes and prices on an equal footing — a large, pricier bottle can easily be cheaper per day than a small premium one.
Estimating daily usage is the key variable. Typical figures: a serum pump ≈ 0.5 ml, a moisturiser application ≈ 0.5–1 g, a shampoo wash ≈ 10–15 ml, a face wash pump ≈ 1–2 ml. If you are unsure, weigh the bottle at the start and end of one week and divide the loss by 7.
Frequently asked questions
Weigh a nearly full bottle, use the product normally for a week, then weigh it again. Divide the weight lost by 7 for your daily average in grams. For liquids you cannot weigh, count the pumps per use and look up the pump volume — typically 0.5–1 ml — on the manufacturer's website.
Creams and balms are sold by weight (grams) because their density varies, so use grams if the label shows a weight. Water-based liquids like micellar water or toners have a density close to 1 g/ml, making ml and g essentially interchangeable for those products.
Yes — it works for any product where you know the total amount and can estimate daily usage. For sunscreen applied to the whole face and neck, a typical daily application is roughly 1–2 ml. For foundation, one pump is usually 0.5–1 ml. Adjust the daily usage field to match your routine.
TG we-Calculate Editorial Team. (2026). Beauty Products Calculator — How Long Will It Last? [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/beauty-products-calculator
TG we-Calculate Editorial Team. "Beauty Products Calculator — How Long Will It Last?." TG we-Calculate. 2026. https://we-calculate.com/calculator/beauty-products-calculator.
TG we-Calculate Editorial Team, "Beauty Products Calculator — How Long Will It Last?," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/beauty-products-calculator
@misc{wecalculate_beauty_products_calculator, title = {Beauty Products Calculator — How Long Will It Last?}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/beauty-products-calculator}}, year = {2026}, note = {TG we-Calculate} }
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