Japan: 125% is a floor, and it steps up past 60 hours in a month
Articles 32 and 37 of the Labour Standards Act set 40 hours a week and eight a day, and require overtime to be paid at not less than 125% of the ordinary rate. That is the lowest statutory premium of any country here that has one at all, a quarter more, against a half in the United States and double in India.
It does not stay at 125%. The rate rises to 150% for hours beyond 60 in a month, and work between 10pm and 5am carries a further 25% of its own, so an overtime hour worked at night also reaches 150%. Both of those are thresholds this calculator cannot see: it works from a weekly overtime figure, and sixty hours a month is roughly fourteen a week averaged across an uneven year. If your overtime is concentrated in busy months, your actual pay is above what this page reports.
Paid leave in Japan depends on how long you have been there. It starts at ten days after six months of continuous service and climbs with tenure to twenty days after six and a half years, so two colleagues on the same salary have genuinely different rates per hour actually worked. The calculator opens on the ten-day entry figure; set it to your own entitlement if you have been in post longer.
Against that, Japan has sixteen public holidays, more than any other country here, which is why the gap between paid hours and worked hours is wider than the modest leave entitlement suggests. Bonuses are the other half of Japanese pay, commonly several months of salary across summer and winter, and no hourly conversion, including this one, captures them.