Chemical Service Timing Calculator

This calculator estimates how long a chemical service should process before you check it, starting from a service-specific base time and scaling it through four modifiers. Service Type sets the base: 30 minutes for permanent color, 35 for lightener/bleach, 15 for relaxer, and 20 for perm (lines 14-18). Hair Type scales that base — fine hair at 0.8, medium at 1.0, coarse at 1.3 (line 21). Levels of Lift adds time only for color and lightener services: the lift modifier is 1 plus 0.15 times (lift levels minus 1), and stays at 1.0 for relaxers and perms where lift is irrelevant (line 24). Product Strength works inversely — gentle products extend time by 15%, standard stays at 1.0, and maximum strength shortens it by 15% (line 27), reflecting that stronger formulas process faster.

Hair Condition further adjusts: virgin hair at 1.0, previously treated at 0.9, damaged at 0.75 (line 30). The product of all modifiers is rounded to whole minutes (line 32), then capped at a service-specific Maximum Safe Time — 50 for lightener, 25 for relaxer, 30 for perm, 45 for color (lines 39, 44). Check Every is 5 minutes for damaged hair or any lightener service, otherwise 10 (line 35); Number of Checks is the capped processing time divided by that interval, floored to at least one (line 36). This is a scheduling aid, not a substitute for strand testing or manufacturer instructions.