The donation to the charity comes from the proceeds of recycling metal and orthopaedic implants following cremation.
Rainsbrook joined the Institute of Cemetery and Crematorium Management's national Recycling of Metals scheme when the crematorium opened its doors more than a decade ago.
Rainsbrook asks all bereaved families to consider donating the metal to the scheme - but only sends it for recycling with the blessing of the next of kin.
The crematorium has decided to donate the proceeds from the past year's recycling to the Arden Angels, founded by Rugby woman Tracie Mills, who was diagnosed with breast cancer in 2013.
Following intensive chemotherapy and a double mastectomy, Tracie decided to raise £1,000 to buy a new chemotherapy chair for the Arden Centre at Coventry's University Hospital to thank staff for the care and support she received during her treatment.
But with the support of family and friends - quickly joined by fellow Rugby residents and businesses - the fund-raising drive raced beyond Tracie's original target and currently stands at £169,718.
The Arden Angels have now bought 20 new chemotherapy chairs for the Arden Centre and, thanks to a £30,000 donation, helped open the Laurel Centre at Rugby's Hospital of St Cross, a specialist breast surgery care unit.
Nickie Brightwell, Tracie's friend and fellow Arden Angel, said: "Tracie is a totally selfless lady and a force of nature, a woman to be reckoned with.
"While undergoing all her treatment over 11 years she has never faltered in wishing to give back to our local cancer centres - the Maple Unit at the Hospital of St Cross and the Arden Centre at University Hospital - and the cancer community.
"All monies raised by the Arden Angels goes to help the patients, families and staff and their care at the centres locally."
Rainsbrook Crematorium, off Ashlawn Road, was built by Rugby Borough Council and Daventry District Council, and opened in the spring of 2014.
Daventry District Council became part of the new West Northamptonshire Council when it was formed in 2021.
Cllr Claire Edwards, Rugby Borough Council portfolio holder for communities and homes, regulation and safety, said: "The Recycling of Metals scheme relies on donations and we can only recycle metal and orthopaedic implants with the blessing of relatives.
"We understand it's a very sensitive subject but we hope bereaved families and friends can take a little comfort from knowing the money raised through recycling has supported a wonderful charity."
Cllr Jo Gilford, chairman of West Northamptonshire Council, said: "I am immensely proud of the partnership between Rainsbrook Crematorium and the Institute of Cemetery and Crematorium Management's national Recycling of Metals scheme.
"This generous donation of £12,500, derived from the recycling of metals, shows the commitment to supporting vital community initiatives.
"The Arden Angels' dedication to enhancing cancer care is truly inspiring. Together, we are making a significant impact on the lives of those in need."
Cllr Noreen New, Rugby Borough Council's Liberal Democrat spokesperson for communities and homes, regulation and safety, said: "It is reassuring for families who have so kindly donated to the recycling scheme that the money raised is going to such a worthy cause."
For more information about Rainsbrook Crematorium, visit www.rainsbrookcrematorium.co.uk