The Sunscreen Supply Plan

How much sunscreen a family trip takes: a full coat for everyone, every coat the reapply rule calls for, the bottles to pack rounded up, the date check for the bottles you own, and the cheapest set of whole bottles

SunStoke's Sunscreen Amount Calculator tells you how much one coat of sunscreen takes on one body, and never less than the FDA's one ounce for a whole body. It stops there. Nothing on the site says how many coats a trip takes for a whole family, how many bottles that is, or whether the bottles already in the cupboard are still in date. This book counts a full coat for everyone, every coat the FDA's reapply rule calls for (at least every two hours, and more often if you're sweating or swimming), and the trip total in whole bottles, rounded up. In its worked example (all figures are examples), two adults and two children, five days away, four hours outdoors a day with one swim, need 1,959 mL in swimsuits: nine 8 fl oz bottles, $116.91. With swim shirts over the torso, the one bottle in the cupboard still in date on the last day, and the cheapest set of whole bottles that holds the rest, the same trip comes to $56.97, and not one coat on bare skin is thinner. It is a quantity and budget book only: it gives no time in the sun, no burn time, no tanning time and nothing on vitamin D, and it quotes the FDA, the American Academy of Dermatology and WHO word for word, including that sunscreen is not for extending time in the sun. Every rounding goes toward more sunscreen. Every figure is computed by code and tagged as an example; it promises no price and no saving. Included: 24 printable pages (7 steps, 4 working pages, reference tables, a quickstart) and a personalised sheet worked from the body size, areas and coats you enter in the Sunscreen Amount Calculator: your coat, your coats a day, and the bottles a trip takes.

Look inside

Two full pages from the book, exactly as printed. Click either to read it at full size before you decide.

What is in it

• Step 1: one full coat for each person at 2 mg/cm2, never under the FDA's one ounce for a whole body, rounded up
• Step 2: the coats a day at the FDA's reapply rule, hours out divided by two rounded up, plus one after every swim
• Step 3: the trip total for the whole family in whole bottles, rounded up
• Step 4: cover up first: covered skin out of the count, bare skin at full strength
• Step 5: the date check for the bottles you own: the printed date, or three years after purchase (FDA)
• Step 6: the cost of one coat from each bottle, and the cheapest set of whole bottles that holds the rest
• Step 7: packing: checked bags, a bottle in every day bag, kept in the shade, and a day card
• Four working pages: a family amount sheet, a coat counter, a bottle and price sheet, a cut-out cupboard card and day card
• Reference tables: one coat by body size and clothing, bottles by group size and days, coats a day
• A personalised sheet from your own coat: your coat in mL and fl oz, your coats a day, and the bottles a trip takes

The plan picks up where the free Sunscreen Amount Calculatorleaves off. The calculator gives one coat for one body, never below the FDA's one ounce for a whole body; the book counts a coat for everyone on the trip, every coat the FDA's reapply rule calls for (at least every two hours, and more often if you're sweating or swimming), and the trip total in whole bottles, rounded up. Then it takes the skin clothing covers out of the count, checks the dates on the bottles you already have (no printed date means expired three years after purchase, says the FDA), finds the cheapest set of whole bottles that holds the rest, and packs them. Every figure in it is an example, and it promises no price and no saving. It is a quantity and budget book only: it gives no time in the sun, no burn time, no tanning time and nothing on vitamin D. Sunscreen is not for extending time in the sun.