Charging for on-call days?

I'm moving to a new city and setting up work in advance. I was originally going to split my time between two families, but one of them fell through. I was already planning to be with the other family 2 days a week and now that the other position fell through they're asking about keeping me on-call for two more days a week. The grandparents usually watch the kids those days, but apparently they travel sometimes and the parents like the idea of knowing that I would be consistently available to pick up days if needed. So the majority of the time it would only be two days a week, but sometimes 4. It would typically be a 9-hour workday.

How would you handle this? What would be standard? They were asking about a flat rate per week to cover it, but I don't know how that would work. I was thinking about purposing that they pay me my usual hourly rate for the days that I work, and 50% of my rate for those days/hours that I reserve to be on-call for them. Then if they do need me, they pay my usual hourly rate for those days. Would that be a reasonable arrangement?

I'm trying to figure out what would be fair for everyone. I know that in the past I've sold myself short and charged much less than I should have. I feel like I have a more appropriate hourly rate now, but am really unsure of how to set something like this up. I know my tendency is to be a pushover and accept too little. I would really appreciate input from others!

Comments

I hate on call. For me the family has to pay my full rate to keep me on call. Otherwise I could and would be giving up other paying work to hold those hours open. If they are going to pay me they should just use me.
it's just not worth it to me to not know my schedule ahead of time.

For some people it works.

No way ... unless the retainer is Full Pay! You most likely NEED full-time work. So keep yourself free to find another family who needs you on your "days off". (Signed - a Recovering Pushover!)

Sounds like you will only be working 2 days, not 4 days. It is Not a Definite 4 day job. If you do not charge them the full hourly rate then you are giving up work and pay. I would go online and register as a Last minute on-call nanny available for the 3 days you are off and Not Getting Paid for. Care.com has "Short Notice Nannies" registered and see what they charge? I have thought of this same thing myself. My new family told me I would be off 1 day per week. So far its the same day each week, so I can plan, and this week they gave me the Entire Months Schedule. So I can schedule a 5th day with another family. I have 2-3 past employers that hire me for sick days or nights for a date night. I charge them my Full rate, why would I cut myself short? No discount, charge Your Full rate and if they want you to Be Open on that week, they need to pay you. No Deals. You are giving up your week to be On-Call for them. miss pat